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Articles containing the keyword 'pH'.

Category: Research article

article id 10247, category Research article
Agnese Marcelli, Walter Mattioli, Nicola Puletti, Francesco Chianucci, Damiano Gianelle, Mirko Grotti, Gherardo Chirici, Giovanni D' Amico, Saverio Francini, Davide Travaglini, Lorenzo Fattorini, Piermaria Corona. (2020). Large-scale two-phase estimation of wood production by poplar plantations exploiting Sentinel-2 data as auxiliary information. Silva Fennica vol. 54 no. 2 article id 10247. https://doi.org/10.14214/sf.10247
Highlights: A two-phase sampling for large-scale assessment of fast-growing forest crops is developed; Vegetation indices from Sentinel-2 are exploited in a linear regression estimator; The linear regression estimator turns out to be better than the estimator based on the sole sample information; The approach represents a reference for supporting outside-forest resource monitoring and assessment.

Growing demand for wood products, combined with efforts to conserve natural forests, have supported a steady increase in the global extent of planted forests. Here, a two-phase sampling strategy for large-scale assessment of the total area and the total wood volume of fast-growing forest tree crops within agricultural land is presented. The first phase is performed using tessellation stratified sampling on high-resolution remotely sensed imagery and is sufficient for estimating the total area of plantations by means of a Monte Carlo integration estimator. The second phase is performed using stratified sampling of the plantations selected in the first phase and is aimed at estimating total wood volume by means of an approximation of the first-phase Horvitz-Thompson estimator. Vegetation indices from Sentinel-2 are exploited as freely available auxiliary information in a linear regression estimator to improve the design-based precision of the estimator based on the sole sample data. Estimators of the totals and of the design-based variances of total estimators are presented. A simulation study is developed in order to check the design-based performance of the two alternative estimators under several artificial distributions supposed for poplar plantations (random, clustered, spatially trended). An application in Northern Italy is also reported. The regression estimator turns out to be invariably better than that based on the sole sample information. Possible integrations of the proposed sampling scheme with conventional national forest inventories adopting tessellation stratified sampling in the first phase are discussed.

  • Marcelli, University of Tuscia, Department for Innovation in Biological, Agro-food and Forest systems, Viterbo, Italy; Fondazione Edmund Mach, Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, San Michele all’Adige, Italy ORCID ID:E-mail: agnese.marcelli@student.unisi.it (email)
  • Mattioli, University of Tuscia, Department for Innovation in Biological, Agro-food and Forest systems, Viterbo, Italy; CREA, Research Centre for Forestry and Wood, Arezzo, Italy ORCID ID:E-mail: walter.mattioli@crea.gov.it
  • Puletti, CREA, Research Centre for Forestry and Wood, Arezzo, Italy ORCID ID:E-mail: nicola.puletti@crea.gov.it
  • Chianucci, CREA, Research Centre for Forestry and Wood, Arezzo, Italy ORCID ID:E-mail: fchianucci@gmail.com
  • Gianelle, Fondazione Edmund Mach, Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, San Michele all’Adige, Italy ORCID ID:E-mail: damiano.gianelle@fmach.it
  • Grotti, CREA, Research Centre for Forestry and Wood, Arezzo, Italy; University of Roma La Sapienza, Department of Architecture and Design, Rome, Italy ORCID ID:E-mail: mirkogrotti@gmail.com
  • Chirici, University of Firenze, Department of Agriculture, Food, Environment and Forestry, Florence, Italy ORCID ID:E-mail: gherardo.chirici@unifi.it
  • D' Amico, University of Firenze, Department of Agriculture, Food, Environment and Forestry, Florence, Italy ORCID ID:E-mail: giovanni.damico@unifi.it
  • Francini, University of Firenze, Department of Agriculture, Food, Environment and Forestry, Florence, Italy; University of Molise, Department of Agricultural, Environmental and Food Sciences, Campobasso, Italy ORCID ID:E-mail: saverio.francini@gmail.com
  • Travaglini, University of Firenze, Department of Agriculture, Food, Environment and Forestry, Florence, Italy ORCID ID:E-mail: davide.travaglini@unifi.it
  • Fattorini, University of Siena, Department of Economics and Statistics, Siena, Italy ORCID ID:E-mail: lorenzo.fattorini@unisi.it
  • Corona, CREA, Research Centre for Forestry and Wood, Arezzo, Italy ORCID ID:E-mail: piermaria.corona@crea.gov.it
article id 10247, category Research article
Agnese Marcelli, Walter Mattioli, Nicola Puletti, Francesco Chianucci, Damiano Gianelle, Mirko Grotti, Gherardo Chirici, Giovanni D' Amico, Saverio Francini, Davide Travaglini, Lorenzo Fattorini, Piermaria Corona. (2020). Large-scale two-phase estimation of wood production by poplar plantations exploiting Sentinel-2 data as auxiliary information. Silva Fennica vol. 54 no. 2 article id 10247. https://doi.org/10.14214/sf.10247
Highlights: A two-phase sampling for large-scale assessment of fast-growing forest crops is developed; Vegetation indices from Sentinel-2 are exploited in a linear regression estimator; The linear regression estimator turns out to be better than the estimator based on the sole sample information; The approach represents a reference for supporting outside-forest resource monitoring and assessment.

Growing demand for wood products, combined with efforts to conserve natural forests, have supported a steady increase in the global extent of planted forests. Here, a two-phase sampling strategy for large-scale assessment of the total area and the total wood volume of fast-growing forest tree crops within agricultural land is presented. The first phase is performed using tessellation stratified sampling on high-resolution remotely sensed imagery and is sufficient for estimating the total area of plantations by means of a Monte Carlo integration estimator. The second phase is performed using stratified sampling of the plantations selected in the first phase and is aimed at estimating total wood volume by means of an approximation of the first-phase Horvitz-Thompson estimator. Vegetation indices from Sentinel-2 are exploited as freely available auxiliary information in a linear regression estimator to improve the design-based precision of the estimator based on the sole sample data. Estimators of the totals and of the design-based variances of total estimators are presented. A simulation study is developed in order to check the design-based performance of the two alternative estimators under several artificial distributions supposed for poplar plantations (random, clustered, spatially trended). An application in Northern Italy is also reported. The regression estimator turns out to be invariably better than that based on the sole sample information. Possible integrations of the proposed sampling scheme with conventional national forest inventories adopting tessellation stratified sampling in the first phase are discussed.

  • Marcelli, University of Tuscia, Department for Innovation in Biological, Agro-food and Forest systems, Viterbo, Italy; Fondazione Edmund Mach, Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, San Michele all’Adige, Italy ORCID ID:E-mail: agnese.marcelli@student.unisi.it (email)
  • Mattioli, University of Tuscia, Department for Innovation in Biological, Agro-food and Forest systems, Viterbo, Italy; CREA, Research Centre for Forestry and Wood, Arezzo, Italy ORCID ID:E-mail: walter.mattioli@crea.gov.it
  • Puletti, CREA, Research Centre for Forestry and Wood, Arezzo, Italy ORCID ID:E-mail: nicola.puletti@crea.gov.it
  • Chianucci, CREA, Research Centre for Forestry and Wood, Arezzo, Italy ORCID ID:E-mail: fchianucci@gmail.com
  • Gianelle, Fondazione Edmund Mach, Department of Sustainable Agro-Ecosystems and Bioresources, Research and Innovation Centre, San Michele all’Adige, Italy ORCID ID:E-mail: damiano.gianelle@fmach.it
  • Grotti, CREA, Research Centre for Forestry and Wood, Arezzo, Italy; University of Roma La Sapienza, Department of Architecture and Design, Rome, Italy ORCID ID:E-mail: mirkogrotti@gmail.com
  • Chirici, University of Firenze, Department of Agriculture, Food, Environment and Forestry, Florence, Italy ORCID ID:E-mail: gherardo.chirici@unifi.it
  • D' Amico, University of Firenze, Department of Agriculture, Food, Environment and Forestry, Florence, Italy ORCID ID:E-mail: giovanni.damico@unifi.it
  • Francini, University of Firenze, Department of Agriculture, Food, Environment and Forestry, Florence, Italy; University of Molise, Department of Agricultural, Environmental and Food Sciences, Campobasso, Italy ORCID ID:E-mail: saverio.francini@gmail.com
  • Travaglini, University of Firenze, Department of Agriculture, Food, Environment and Forestry, Florence, Italy ORCID ID:E-mail: davide.travaglini@unifi.it
  • Fattorini, University of Siena, Department of Economics and Statistics, Siena, Italy ORCID ID:E-mail: lorenzo.fattorini@unisi.it
  • Corona, CREA, Research Centre for Forestry and Wood, Arezzo, Italy ORCID ID:E-mail: piermaria.corona@crea.gov.it
article id 10143, category Research article
Olga Grigorieva, Olga Brovkina, Alisher Saidov. (2020). An original method for tree species classification using multitemporal multispectral and hyperspectral satellite data. Silva Fennica vol. 54 no. 2 article id 10143. https://doi.org/10.14214/sf.10143
Highlights: Differences between spectral reflectance of tree species are statistically significant in the sub-seasons of spring, first half of summer, and main autumn; Classification using multitemporal multispectral data is more productive than is classification using a single hyperspectral image; the method improves recent forest mapping in the study regions.

This study proposes an original method for tree species classification by satellite remote sensing. The method uses multitemporal multispectral (Landsat OLI) and hyperspectral (Resurs-P) data acquired from determined vegetation periods. The method is based on an original database of spectral features taking into account seasonal variations of tree species spectra. Changes in the spectral signatures of forest classes are analyzed and new spectral–temporal features are created for the classification. Study sites are located in the Czech Republic and northwest (NW) Russia. The differences in spectral reflectance between tree species are shown as statistically significant in the sub-seasons of spring, first half of summer, and main autumn for both study sites. Most of the errors are related to the classification of deciduous species and misclassification of birch as pine (NW Russia site), pine as mixture of pine and spruce, and pine as mixture of spruce and beech (Czech site). Forest species are mapped with accuracy as high as 80% (NW Russia site) and 81% (Czech site). The classification using multitemporal multispectral data has a kappa coefficient 1.7 times higher than does that of classification using a single multispectral image and 1.3 times greater than that of the classification using single hyperspectral images. Potentially, classification accuracy can be improved by the method when applying multitemporal satellite hyperspectral data, such as in using new, near-future products EnMap and/or HyspIRI with high revisit time.

  • Grigorieva, A.F. Mozhaysky’s Military-Space Academy, Krasnogo Kursanta Street 19a, 197198, Saint Petersburg, Russia ORCID ID:E-mail: alenka12003@gmail.com
  • Brovkina, Global Change Research Institute CAS, Bělidla 986/4a, 603 00, Brno, Czech Republic ORCID ID:E-mail: brovkina.o@czechglobe.cz (email)
  • Saidov, A.F. Mozhaysky’s Military-Space Academy, Krasnogo Kursanta Street 19a, 197198, Saint Petersburg, Russia ORCID ID:E-mail: celestial.azura@gmail.com
article id 10242, category Research article
Shisheng Long, Siqi Zeng, Falin Liu, Guangxing Wang. (2020). Influence of slope, aspect and competition index on the height-diameter relationship of Cyclobalanopsis glauca trees for improving prediction of height in mixed forests. Silva Fennica vol. 54 no. 1 article id 10242. https://doi.org/10.14214/sf.10242
Highlights: In this study, the effects of slope, aspect and competition index (CI) on the H-DBH relationship were explored and an improved CI was developed and included to improve predictions of Cyclobalanopsis glauca tree height; It was found that the effects were statistically significant and considering slope, aspect and CI for developing the H-DBH models significantly increased the H prediction accuracy.

Diameter at breast height (DBH) and height (H) of trees are two important variables used in forest management plans. However, collecting the measurements of H is time-consuming and costly. Instead, the H-DBH relationship is modeled and used to estimate H. But, ignoring the effects of slope, aspect and tree competition on the H-DBH relationship often impedes the improvement of H predictions. In this study, to improve predictions of Cyclobalanopsis glauca (Thunb.) Oerst. tree H in mixed forests, we compared eleven H-DBH models and examined the influence of slope and aspect on the H-DBH relationship using 426 trees. We then improved Hegyi competition index and explored its effect on the H predictions by including it in the selected models. Results showed 1) There were statistically significant effects of slope and aspect on the H-DBH relationship; 2) The log transformation and exponential model performed best for sunny- and shady-steep, respectively, and the Gompertz’s model was optimal for both sunny- and shady-gentle; 3) Compared with the whole dataset, the division of the data into the slope and aspect sub-datasets significantly reduced the RMSE of H predictions; 4) Compared with the selected models without competition index, adding the original Hegyi and improved Hegyi_I into the models improved the H predictions but only the models containing the improved Hegyi_I significantly increased the prediction accuracy at the significant level of 0.1. This study implied that modeling the H-DBH relationship under different slopes and aspects and including the improved Hegyi_I provided the great potential to improve the H predictions.

  • Long, Faculty of Forestry, Central South University of Forestry and Technology, Changsha, Hunan 410004, China ORCID ID:E-mail: shisheng3604@21cn.com
  • Zeng, Faculty of Forestry, Central South University of Forestry and Technology, Changsha, Hunan 410004, China ORCID ID:E-mail: zengsiqi@21cn.com
  • Liu, Faculty of Forestry, Central South University of Forestry and Technology, Changsha, Hunan 410004, China ORCID ID:E-mail: liufl680@126.com
  • Wang, Research Center of Forestry Remote Sensing & Information Engineering, Central South University of Forestry and Technology, Changsha 410004, China; Department of Geography and Environmental Resources, Southern Illinois University, Carbondale, IL 62901, USA ORCID ID:E-mail: gxwang@siu.edu (email)
article id 10196, category Research article
Karri Uotila, Jari Miina, Timo Saksa, Ron Store, Kauko Kärkkäinen, Mika Härkönen. (2020). Low cost prediction of time consumption for pre-commercial thinning in Finland. Silva Fennica vol. 54 no. 1 article id 10196. https://doi.org/10.14214/sf.10196
Highlights: Time consumption (TC) in pre-commercial thinning (PCT) can be predicted by variables describing site and stands conditions and previous silvicultural management; Applying variables available in forest resources data the field-assessment of worksite difficulty factors is not needed; The TC model could facilitate the predictions of the labour costs of PCT in forest information systems.

The time consumption (TC) of pre-commercial thinning (PCT) varies greatly among sites, stands and forest workers. The TC in PCT is usually estimated by field-assessed work difficulty factors. In this study, a linear mixed model for the TC in PCT was prepared by utilizing forest resources data (FRD). The modelling data included 11 848 and validation data included 3035 worksites with TC information recorded by forest workers within the period of 2008–2018. The worksites represented a range of site and stand conditions across a broad geographical area in Finland. Site and stand characteristics and previous management logically explained the TC in PCT. The more fertile the site, the more working time was needed in PCT. On sites of medium fertility, TC in the initial PCT increased with stand age by 0.5 h ha–1 yr–1. Site wetness increased the TC. PCT in summer was more time consuming than in spring. Small areas were more time consuming to PCT per hectare than larger ones. The between-forest worker variation involved in the TC was as high as 35% of the variation unexplained by the TC model. The coefficient of determination in validation data was 19.3%, RMSE 4.75 h ha–1 and bias –1.6%. The TC model based on FRD was slightly less precise than the one based on field-assessed work difficulty factors (removal quantity and type and terrain difficulty): RMSE 4.9 h ha–1 vs. 4.1 h ha–1 (52% vs. 43%). The TC model could be connected to forest information systems where it would facilitate the predictions of the labour costs of PCT without field-assessing work difficulty factors.

  • Uotila, Natural Resources Institute Finland (Luke), Natural resources, Latokartanonkaari 9, FI-00790 Helsinki, Finland ORCID ID:E-mail: karri.uotila@luke.fi (email)
  • Miina, Natural Resources Institute Finland (Luke), Natural resources, Yliopistokatu 6 B, FI-80100 Joensuu, Finland ORCID ID:E-mail: jari.miina@luke.fi
  • Saksa, Natural Resources Institute Finland (Luke), Natural resources, Survontie 9, FI-40500 Jyväskylä, Finland ORCID ID:E-mail: timo.saksa@luke.fi
  • Store, Natural Resources Institute Finland (Luke), Bioeconomy and environment, Teknologiakatu 7, FI-67100 Kokkola, Finland ORCID ID:E-mail: ron.store@luke.fi
  • Kärkkäinen, ORCID ID:E-mail: kauko.karkkainen@gmail.com
  • Härkönen, Tornator Oyj, Pielisentie 2–6, FI-81700 Lieksa, Finland ORCID ID:E-mail: mika.harkonen@tornator.fi
article id 10147, category Research article
Mika Aalto, Olli-Jussi Korpinen, Tapio Ranta. (2019). Feedstock availability and moisture content data processing for multi-year simulation of forest biomass supply in energy production. Silva Fennica vol. 53 no. 4 article id 10147. https://doi.org/10.14214/sf.10147
Highlights: A method for allocating forest biomass availability for a multi-year simulation model was developed; The possibility to take the quality change of feedstock into account by moisture estimations was studied; A method to estimate weather data for moisture estimation equations with fewer parameters was presented.

Simulation and modeling have become more common in forest biomass studies. Dynamic simulation has been used to study the supply chain of forest biomass with numerous different models. A robust predictive multi-year model requires biomass availability data, where annual variation is included spatially and temporally. This can be done by using data from enterprises, but in some cases relevant data is not accessible. Another option is to use forest inventory data to estimate biomass availability, but this data must be processed in the correct form to be utilized in the model. This study developed a method for preparing forest inventory data for a multi-year simulation supply model using the theoretical availability of feedstock. Methods for estimating quality changes during roadside storage are also presented, including a possible parameter estimation to decrease the amount of data needed. The methods were tested case by case using the inventory database “Biomass Atlas” and weather data from a weather station in Mikkeli, Finland. The data processing method for biomass allocation produced a reasonable quantity of stands and feedstock, having a realistic annual supply with variation for the demand point. The results of the study indicate that it is possible to estimate moisture content changes using weather data. The estimations decreased the accuracy of the model and, therefore, estimations should be kept minimal. The presented data preparation method can generate a supply of forest biomass for the simulation model, but the validity of the data must be ensured for correct model behavior.

  • Aalto, Lappeenranta-Lahti University of Technology LUT, School of Energy Systems, Laboratory of Bioenergy, Lönnrotinkatu 7, FI-50100 Mikkeli, Finland ORCID ID: https://orcid.org/0000-0002-7768-1145 E-mail: mika.aalto@lut.fi (email)
  • Korpinen, Lappeenranta-Lahti University of Technology LUT, School of Energy Systems, Laboratory of Bioenergy, Lönnrotinkatu 7, FI-50100 Mikkeli, Finland ORCID ID:E-mail: olli-jussi.korpinen@lut.fi
  • Ranta, Lappeenranta-Lahti University of Technology LUT, School of Energy Systems, Laboratory of Bioenergy, Lönnrotinkatu 7, FI-50100 Mikkeli, Finland ORCID ID: https://orcid.org/0000-0001-5464-5136 E-mail: tapio.ranta@lut.fi
article id 9968, category Research article
Hubert Lachowicz, Anna Bieniasz, Rafał Wojtan. (2019). Variability in the basic density of silver birch wood in Poland. Silva Fennica vol. 53 no. 1 article id 9968. https://doi.org/10.14214/sf.9968
Highlights: Location, tree age and forest habitat type, and the interactions between those factors, have a statistically significant impact on the basic density of silver birch wood; The average basic density of silver birch wood increases with the age of the tree.

This work presents the findings of a study concerning variability in the basic density of silver birch (Betula pendula Roth) wood, depending on the geographical location of tree stands, the age and thickness of the trees, the forest habitat type, and interactions between some of these factors. The study was carried out on wood from trees aged approximately 30, 50 and 70 years in 12 forest districts located throughout Poland. In total 4777 wood samples, taken from 306 trees from 51 test plots, were measured. The location, the age of the trees, the thickness of the trees and the forest habitat type, as well as interactions between these factors, proved to have a significant influence on the basic density of silver birch wood. The highest mean values of the basic density of the birch wood were found in Sokołów forest district on the FBF habitat type (549 kg m–3) and in Giżycko forest district on the FMBF habitat type (548 kg m–3). For the entire set of examined material, the average values of the basic density of wood increase with tree age. For the examined material originating in FBF and FMBF habitats the average values of basic density showed no significant differences; however, in the cases of the forest districts of Giżycko, Łobez and Rudziniec, significant differences in the analysed property were observed.

  • Lachowicz, Department of Forest Utilization, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: hubert.lachowicz@wl.sggw.pl
  • Bieniasz, Department of Forest Utilization, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: anna.bieniasz@wl.sggw.pl (email)
  • Wojtan, Laboratory of Dendrometry and Forest Productivity, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: rwojtan@wl.sggw.pl
article id 9968, category Research article
Hubert Lachowicz, Anna Bieniasz, Rafał Wojtan. (2019). Variability in the basic density of silver birch wood in Poland. Silva Fennica vol. 53 no. 1 article id 9968. https://doi.org/10.14214/sf.9968
Highlights: Location, tree age and forest habitat type, and the interactions between those factors, have a statistically significant impact on the basic density of silver birch wood; The average basic density of silver birch wood increases with the age of the tree.

This work presents the findings of a study concerning variability in the basic density of silver birch (Betula pendula Roth) wood, depending on the geographical location of tree stands, the age and thickness of the trees, the forest habitat type, and interactions between some of these factors. The study was carried out on wood from trees aged approximately 30, 50 and 70 years in 12 forest districts located throughout Poland. In total 4777 wood samples, taken from 306 trees from 51 test plots, were measured. The location, the age of the trees, the thickness of the trees and the forest habitat type, as well as interactions between these factors, proved to have a significant influence on the basic density of silver birch wood. The highest mean values of the basic density of the birch wood were found in Sokołów forest district on the FBF habitat type (549 kg m–3) and in Giżycko forest district on the FMBF habitat type (548 kg m–3). For the entire set of examined material, the average values of the basic density of wood increase with tree age. For the examined material originating in FBF and FMBF habitats the average values of basic density showed no significant differences; however, in the cases of the forest districts of Giżycko, Łobez and Rudziniec, significant differences in the analysed property were observed.

  • Lachowicz, Department of Forest Utilization, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: hubert.lachowicz@wl.sggw.pl
  • Bieniasz, Department of Forest Utilization, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: anna.bieniasz@wl.sggw.pl (email)
  • Wojtan, Laboratory of Dendrometry and Forest Productivity, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: rwojtan@wl.sggw.pl
article id 10040, category Research article
Bengt Andersson Gull, Torgny Persson, Aleksey Fedorkov, Tim J. Mullin. (2018). Longitudinal differences in Scots pine shoot elongation. Silva Fennica vol. 52 no. 5 article id 10040. https://doi.org/10.14214/sf.10040
Highlights: More northerly Scots pine origins exhibit earlier onset and cessation of shoot growth; Continental origins show more northern phenological behaviour; Heat accumulation requirements for onset are not fixed and may be lower when accumulating slower; Scots pine may suffer from spring frost due to earlier growth onset in a warming climate; Phenological traits show potential to adapt to new climate conditions by breeding.

Phenology can have a profound effect on growth and climatic adaptability of long-lived, northern tree species such as Scots pine (Pinus sylvestris L.), where the onset of growth in the spring is triggered mainly by accumulated heat, while cessation of growth is related to the joint effect of photoperiod and temperature. In this study, the objectives were: (1) to compare shoot phenology of genetic material from Scandinavia (maritime climate origin) and northern Russia (continental climate origin) sources, under field conditions in both Scandinavia and Russia (maritime and continental growth conditions); and (2) to estimate the heritabilities of phenological parameters. The material used was part of a larger provenance test series involving Scots pine populations and open-pollinated plus-tree families from Russia, Sweden and Finland. Terminal shoot elongation was measured on multiple occasions during the seventh growing season from seed at a trial near Bäcksjön (Sweden) and Syktyvkar (northern Russia). We calculated the regression of relative shoot elongation over accumulated heat sum above +5 °C using an exponential expression. Seedlings of Swedish and Russian provenance had similar heat-sum requirements for growth onset and cessation in both trials. More northern provenances started onset and cessation at a lower temperature sum, but heat accumulation requirements for onset were not fixed. Scots pine may suffer from spring frost due to earlier growth onset in a warming climate. Variation and heritability of phenological traits show potential to adapt Scots pine to new climate conditions by breeding.

  • Andersson Gull, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden ORCID ID: https://orcid.org/0000-0003-3556-3172 E-mail: bengt.anderssongull@skogforsk.se
  • Persson, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden ORCID ID:E-mail: torgny.persson@skogforsk.se
  • Fedorkov, The Institute of Biology of Komi Scientific Centre of the Ural Branch of the Russian Academy of Sciences (IB Komi SC UB RAS), Kommunisticheskaya St., 28, Syktyvkar, 167982, Russia ORCID ID: https://orcid.org/0000-0001-7800-7534 E-mail: fedorkov@ib.komisc.ru
  • Mullin, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden ORCID ID: https://orcid.org/0000-0003-4924-1836 E-mail: tim.mullin@skogforsk.se (email)
article id 10040, category Research article
Bengt Andersson Gull, Torgny Persson, Aleksey Fedorkov, Tim J. Mullin. (2018). Longitudinal differences in Scots pine shoot elongation. Silva Fennica vol. 52 no. 5 article id 10040. https://doi.org/10.14214/sf.10040
Highlights: More northerly Scots pine origins exhibit earlier onset and cessation of shoot growth; Continental origins show more northern phenological behaviour; Heat accumulation requirements for onset are not fixed and may be lower when accumulating slower; Scots pine may suffer from spring frost due to earlier growth onset in a warming climate; Phenological traits show potential to adapt to new climate conditions by breeding.

Phenology can have a profound effect on growth and climatic adaptability of long-lived, northern tree species such as Scots pine (Pinus sylvestris L.), where the onset of growth in the spring is triggered mainly by accumulated heat, while cessation of growth is related to the joint effect of photoperiod and temperature. In this study, the objectives were: (1) to compare shoot phenology of genetic material from Scandinavia (maritime climate origin) and northern Russia (continental climate origin) sources, under field conditions in both Scandinavia and Russia (maritime and continental growth conditions); and (2) to estimate the heritabilities of phenological parameters. The material used was part of a larger provenance test series involving Scots pine populations and open-pollinated plus-tree families from Russia, Sweden and Finland. Terminal shoot elongation was measured on multiple occasions during the seventh growing season from seed at a trial near Bäcksjön (Sweden) and Syktyvkar (northern Russia). We calculated the regression of relative shoot elongation over accumulated heat sum above +5 °C using an exponential expression. Seedlings of Swedish and Russian provenance had similar heat-sum requirements for growth onset and cessation in both trials. More northern provenances started onset and cessation at a lower temperature sum, but heat accumulation requirements for onset were not fixed. Scots pine may suffer from spring frost due to earlier growth onset in a warming climate. Variation and heritability of phenological traits show potential to adapt Scots pine to new climate conditions by breeding.

  • Andersson Gull, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden ORCID ID: https://orcid.org/0000-0003-3556-3172 E-mail: bengt.anderssongull@skogforsk.se
  • Persson, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden ORCID ID:E-mail: torgny.persson@skogforsk.se
  • Fedorkov, The Institute of Biology of Komi Scientific Centre of the Ural Branch of the Russian Academy of Sciences (IB Komi SC UB RAS), Kommunisticheskaya St., 28, Syktyvkar, 167982, Russia ORCID ID: https://orcid.org/0000-0001-7800-7534 E-mail: fedorkov@ib.komisc.ru
  • Mullin, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden ORCID ID: https://orcid.org/0000-0003-4924-1836 E-mail: tim.mullin@skogforsk.se (email)
article id 10006, category Research article
Matti Maltamo, Tomi Karjalainen, Jaakko Repola, Jari Vauhkonen. (2018). Incorporating tree- and stand-level information on crown base height into multivariate forest management inventories based on airborne laser scanning. Silva Fennica vol. 52 no. 3 article id 10006. https://doi.org/10.14214/sf.10006
Highlights: The most accurate tree-level alternative is to include crown base height (CBH) to nearest neighbour imputation; Also mixed-effects models can be applied to predict CBH using tree attributes and airborne laser scanning (ALS) metrics; CBH prediction can be included with an accuracy of 1–1.5 m to forest management inventory applications.

This study examines the alternatives to include crown base height (CBH) predictions in operational forest inventories based on airborne laser scanning (ALS) data. We studied 265 field sample plots in a strongly pine-dominated area in northeastern Finland. The CBH prediction alternatives used area-based metrics of sparse ALS data to produce this attribute by means of: 1) Tree-level imputation based on the k-nearest neighbor (k-nn) method and full field-measured tree lists including CBH observations as reference data; 2) Tree-level mixed-effects model (LME) prediction based on tree diameter (DBH) and height and ALS metrics as predictors of the models; 3) Plot-level prediction based on analyzing the computational geometry and topology of the ALS point clouds; and 4) Plot-level regression analysis using average CBH observations of the plots for model fitting. The results showed that all of the methods predicted CBH with an accuracy of 1–1.5 m. The plot-level regression model was the most accurate alternative, although alternatives producing tree-level information may be more interesting for inventories aiming at forest management planning. For this purpose, k-nn approach is promising and it only requires that field measurements of CBH is added to the tree lists used as reference data. Alternatively, the LME-approach produced good results especially in the case of dominant trees.

  • Maltamo, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: matti.maltamo@uef.fi (email)
  • Karjalainen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: tomimkarjalainen@gmail.com
  • Repola, Natural Resources Institute of Finland (Luke), Natural resources, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@luke.fi
  • Vauhkonen, Natural Resources Institute of Finland (Luke), Bioeconomy and environment, Yliopistokatu 6, 80100 Joensuu, Finland ORCID ID:E-mail: jari.vauhkonen@luke.fi
article id 7721, category Research article
Sakari Tuominen, Andras Balazs, Eija Honkavaara, Ilkka Pölönen, Heikki Saari, Teemu Hakala, Niko Viljanen. (2017). Hyperspectral UAV-imagery and photogrammetric canopy height model in estimating forest stand variables. Silva Fennica vol. 51 no. 5 article id 7721. https://doi.org/10.14214/sf.7721
Highlights: Hyperspectral imagery and photogrammetric 3D point cloud based on RGB imagery were acquired under weather conditions changing from cloudy to sunny; Calibration of hyperspectral imagery was required for compensating the effect of varying weather conditions; The combination of hyperspectral imagery and photogrammetric point cloud data resulted in accurate forest estimates, especially for volumes per tree species.

Remote sensing using unmanned aerial vehicle (UAV) -borne sensors is currently a highly interesting approach for the estimation of forest characteristics. 3D remote sensing data from airborne laser scanning or digital stereo photogrammetry enable highly accurate estimation of forest variables related to the volume of growing stock and dimension of the trees, whereas recognition of tree species dominance and proportion of different tree species has been a major complication in remote sensing-based estimation of stand variables. In this study the use of UAV-borne hyperspectral imagery was examined in combination with a high-resolution photogrammetric canopy height model in estimating forest variables of 298 sample plots. Data were captured from eleven separate test sites under weather conditions varying from sunny to cloudy and partially cloudy. Both calibrated hyperspectral reflectance images and uncalibrated imagery were tested in combination with a canopy height model based on RGB camera imagery using the k-nearest neighbour estimation method. The results indicate that this data combination allows accurate estimation of stand volume, mean height and diameter: the best relative RMSE values for those variables were 22.7%, 7.4% and 14.7%, respectively. In estimating volume and dimension-related variables, the use of a calibrated image mosaic did not bring significant improvement in the results. In estimating the volumes of individual tree species, the use of calibrated hyperspectral imagery generally brought marked improvement in the estimation accuracy; the best relative RMSE values for the volumes for pine, spruce, larch and broadleaved trees were 34.5%, 57.2%, 45.7% and 42.0%, respectively.

  • Tuominen, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID: http://orcid.org/0000-0001-5429-3433 E-mail: sakari.tuominen@luke.fi (email)
  • Balazs, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID:E-mail: andras.balazs@luke.fi
  • Honkavaara, Finnish Geospatial Research Institute, National Land Survey of Finland, Geodeetinrinne 2, FI-02430 Masala, Finland ORCID ID:E-mail: eija.honkavaara@nls.fi
  • Pölönen, University of Jyväskylä, Faculty of Information Technology, P.O. Box 35, FI-40014 Jyväskylä, Finland ORCID ID:E-mail: ilkka.polonen@jyu.fi
  • Saari, VTT Microelectronics, P.O. Box 1000, FI-02044 VTT, Finland ORCID ID:E-mail: heikki.saari@vtt.fi
  • Hakala, Finnish Geospatial Research Institute, National Land Survey of Finland, Geodeetinrinne 2, FI-02430 Masala, Finland ORCID ID:E-mail: teemu.hakala@nls.fi
  • Viljanen, Finnish Geospatial Research Institute, National Land Survey of Finland, Geodeetinrinne 2, FI-02430 Masala, Finland ORCID ID:E-mail: niko.viljanen@nls.fi
article id 7721, category Research article
Sakari Tuominen, Andras Balazs, Eija Honkavaara, Ilkka Pölönen, Heikki Saari, Teemu Hakala, Niko Viljanen. (2017). Hyperspectral UAV-imagery and photogrammetric canopy height model in estimating forest stand variables. Silva Fennica vol. 51 no. 5 article id 7721. https://doi.org/10.14214/sf.7721
Highlights: Hyperspectral imagery and photogrammetric 3D point cloud based on RGB imagery were acquired under weather conditions changing from cloudy to sunny; Calibration of hyperspectral imagery was required for compensating the effect of varying weather conditions; The combination of hyperspectral imagery and photogrammetric point cloud data resulted in accurate forest estimates, especially for volumes per tree species.

Remote sensing using unmanned aerial vehicle (UAV) -borne sensors is currently a highly interesting approach for the estimation of forest characteristics. 3D remote sensing data from airborne laser scanning or digital stereo photogrammetry enable highly accurate estimation of forest variables related to the volume of growing stock and dimension of the trees, whereas recognition of tree species dominance and proportion of different tree species has been a major complication in remote sensing-based estimation of stand variables. In this study the use of UAV-borne hyperspectral imagery was examined in combination with a high-resolution photogrammetric canopy height model in estimating forest variables of 298 sample plots. Data were captured from eleven separate test sites under weather conditions varying from sunny to cloudy and partially cloudy. Both calibrated hyperspectral reflectance images and uncalibrated imagery were tested in combination with a canopy height model based on RGB camera imagery using the k-nearest neighbour estimation method. The results indicate that this data combination allows accurate estimation of stand volume, mean height and diameter: the best relative RMSE values for those variables were 22.7%, 7.4% and 14.7%, respectively. In estimating volume and dimension-related variables, the use of a calibrated image mosaic did not bring significant improvement in the results. In estimating the volumes of individual tree species, the use of calibrated hyperspectral imagery generally brought marked improvement in the estimation accuracy; the best relative RMSE values for the volumes for pine, spruce, larch and broadleaved trees were 34.5%, 57.2%, 45.7% and 42.0%, respectively.

  • Tuominen, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID: http://orcid.org/0000-0001-5429-3433 E-mail: sakari.tuominen@luke.fi (email)
  • Balazs, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID:E-mail: andras.balazs@luke.fi
  • Honkavaara, Finnish Geospatial Research Institute, National Land Survey of Finland, Geodeetinrinne 2, FI-02430 Masala, Finland ORCID ID:E-mail: eija.honkavaara@nls.fi
  • Pölönen, University of Jyväskylä, Faculty of Information Technology, P.O. Box 35, FI-40014 Jyväskylä, Finland ORCID ID:E-mail: ilkka.polonen@jyu.fi
  • Saari, VTT Microelectronics, P.O. Box 1000, FI-02044 VTT, Finland ORCID ID:E-mail: heikki.saari@vtt.fi
  • Hakala, Finnish Geospatial Research Institute, National Land Survey of Finland, Geodeetinrinne 2, FI-02430 Masala, Finland ORCID ID:E-mail: teemu.hakala@nls.fi
  • Viljanen, Finnish Geospatial Research Institute, National Land Survey of Finland, Geodeetinrinne 2, FI-02430 Masala, Finland ORCID ID:E-mail: niko.viljanen@nls.fi
article id 7753, category Research article
Aarne Hovi, Pekka Raitio, Miina Rautiainen. (2017). A spectral analysis of 25 boreal tree species. Silva Fennica vol. 51 no. 4 article id 7753. https://doi.org/10.14214/sf.7753
Highlights: An extensive spectral library containing leaf and needle reflectance and transmittance spectra was collected; The spectra openly available in SPECCHIO Spectral Information System; Effects of tree species, leaf/needle side, canopy position, and needle age on spectra were quantified; Seasonal variations were measured for four species; Spectra analysis highlights the importance of shortwave-infrared region in separating tree species.

Spectral libraries have a fundamental role in the development of interpretation methods for airborne and satellite-borne remote sensing data. This paper presents to-date the largest spectral measurement campaign of boreal tree species. Reflectance and transmittance spectra of over 600 leaf and needle samples from 25 species were measured in the Helsinki area (Finland) using integrating sphere systems attached to an ASD FieldSpec 4 spectroradiometer. Factors influencing the spectra and red edge inflection point (REIP) were quantified using one-way analysis of variance. Tree species differed most in the shortwave-infrared (1500–2500 nm) and least in the visible (400–700 nm) wavelength region. Species belonging to same genera showed similar spectral characteristics. Upper (adaxial) and lower (abaxial) leaf sides differed most in the visible region. Canopy position (sunlit/shaded) had a minor role in explaining spectral variation. For evergreen conifers, current and previous year needles differed in their spectra, current-year needles resembling those of broadleaved and deciduous conifers. Two broadleaved species were monitored throughout the growing season (May–October), and two conifers were measured twice during summer (June, September). Rapid changes were observed in the spectra in early spring and late autumn, whereas seasonal variations during summer months were relatively small for both broadleaved and coniferous species. Based on our results, shortwave-infrared seems promising in separating tree species, although it is to-date least studied. The spectral library reported here (Version 1.0) is publicly available through the SPECCHIO Spectral Information System.

  • Hovi, Aalto University, Department of Built Environment, P.O. Box 14100, FI-00076 Aalto, Finland ORCID ID:E-mail: aarne.hovi@aalto.fi (email)
  • Raitio, Aalto University, Department of Built Environment, P.O. Box 14100, FI-00076 Aalto, Finland ORCID ID:E-mail: pekka.raitio@aalto.fi
  • Rautiainen, Aalto University, Department of Built Environment, P.O. Box 14100, FI-00076 Aalto, Finland; Aalto University, Department of Electronics and Nanoengineering, P.O. Box 15500, FI-00076 Aalto, Finland ORCID ID:E-mail: miina.a.rautiainen@aalto.fi
article id 7743, category Research article
Sakari Tuominen, Timo Pitkänen, Andras Balazs, Annika Kangas. (2017). Improving Finnish Multi-Source National Forest Inventory by 3D aerial imaging. Silva Fennica vol. 51 no. 4 article id 7743. https://doi.org/10.14214/sf.7743
Highlights: 3D aerial imaging provides a feasible method for estimating forest variables in the form of thematic maps in large area inventories; Photogrammetric 3D data based on aerial imagery that was originally acquired for orthomosaic production was tested in estimating stand variables; Photogrammetric 3D data highly improved the accuracy of forest estimates compared to traditional 2D remote sensing imagery.

Optical 2D remote sensing techniques such as aerial photographing and satellite imaging have been used in forest inventory for a long time. During the last 15 years, airborne laser scanning (ALS) has been adopted in many countries for the estimation of forest attributes at stand and sub-stand levels. Compared to optical remote sensing data sources, ALS data are particularly well-suited for the estimation of forest attributes related to the physical dimensions of trees due to its 3D information. Similar to ALS, it is possible to derive a 3D forest canopy model based on aerial imagery using digital aerial photogrammetry. In this study, we compared the accuracy and spatial characteristics of 2D satellite and aerial imagery as well as 3D ALS and photogrammetric remote sensing data in the estimation of forest inventory variables using k-NN imputation and 2469 National Forest Inventory (NFI) sample plots in a study area covering approximately 5800 km2. Both 2D data were very close to each other in terms of accuracy, as were both the 3D materials. On the other hand, the difference between the 2D and 3D materials was very clear. The 3D data produce a map where the hotspots of volume, for instance, are much clearer than with 2D remote sensing imagery. The spatial correlation in the map produced with 2D data shows a lower short-range correlation, but the correlations approach the same level after 200 meters. The difference may be of importance, for instance, when analyzing the efficiency of different sampling designs and when estimating harvesting potential.

  • Tuominen, Natural Resources Institute Finland (Luke), Economics and Society, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID:E-mail: sakari.tuominen@luke.fi (email)
  • Pitkänen, Natural Resources Institute Finland (Luke), Economics and Society, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID:E-mail: timo.p.pitkanen@luke.fi
  • Balazs, Natural Resources Institute Finland (Luke), Economics and Society, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID:E-mail: andras.balazs@luke.fi
  • Kangas, Natural Resources Institute Finland (Luke), Economics and Society, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: Annika.Kangas@luke.fi
article id 1760, category Research article
Marek Fajstavr, Kyriaki Giagli, Hanuš Vavrčík, Vladimír Gryc, Josef Urban. (2017). The effect of stem girdling on xylem and phloem formation in Scots pine. Silva Fennica vol. 51 no. 4 article id 1760. https://doi.org/10.14214/sf.1760
Highlights: Stem girdling ceased the cambial activity, below the girdled area, immediately after the removal of the bark strip; Pinus sylvestris survived for up to two years after stem girdling; The girdled trees formed phloem cells above the girdled area but failed to form latewood cells in the next growing season.

Scots pine (Pinus sylvestris L.) is a resilient, wide spread species. This paper reports on the xylem and phloem cell formation process, before and after, the species was put under artificial stress by stem girdling. Microcore method was applied to a healthy control group and a standing group of girdled trees within an 80-year-old pine forest for two consecutive growing seasons (2013 and 2014). The stem girdling was applied in the middle of the first growing season (July 2013). Cambial activity timings (onset and cessation of cell division), cell formation intensity, cell differentiation, and the dynamics of the annual radial increment in the stem were analyzed. Cambial activity was inhibited and eventually ceased below the stem girdling immediately after the removal of the strip. Therefore, no latewood tracheids were formed. However, above the stem girdling and in the control trees, cell formation and tissue differentiation continued until the end of the growing season, with the girdled trees moving at a less intensive pace but for a longer period of time. During the following growing season (2014), the cambial zone was reactivated only above the stem girdling, not below, and eventually the girdled trees died. In 2014, the onset of the cambial activity was delayed and the division rate of the cells was slower in the girdled trees. Furthermore, the girdled trees formed less phloem cells than the control trees.

  • Fajstavr, Department of Wood Science, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemedelska 3, 613 00 Brno, Czech Republic ORCID ID:E-mail: fajstavr.marek@seznam.cz (email)
  • Giagli, Department of Wood Science, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemedelska 3, 613 00 Brno, Czech Republic ORCID ID:E-mail: kyriaki.giagli@mendelu.cz
  • Vavrčík, Department of Wood Science, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemedelska 3, 613 00 Brno, Czech Republic ORCID ID:E-mail: vavrcik@mendelu.cz
  • Gryc, Department of Wood Science, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemedelska 3, 613 00 Brno, Czech Republic ORCID ID:E-mail: gryc@mendelu.cz
  • Urban, Department of Forest Botany, Dendrology and Geobiocenology, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemedelska 3, 613 00 Brno, Czech Republic;  Siberian Federal University, Svobodnyj Prospect 79, Krasnoyarsk, 660041 Krasnoyarsk, Russia ORCID ID:E-mail: josef.urban@email.cz
article id 7001, category Research article
Fei-Fei Zhai, Jun-Xiang Liu, Zhen-Jian Li, Jin-Mei Mao, Yong-Qiang Qian, Lei Han, Zhen-Yuan Sun. (2017). Assessing genetic diversity and population structure of Salix viminalis across Ergun and West Liao basin. Silva Fennica vol. 51 no. 3 article id 7001. https://doi.org/10.14214/sf.7001
Highlights: High genetic diversity and moderate population differentiation were detected in twelve Salix viminalis populations; Populations from Ergun basin presented higher genetic diversity than populations from West Liao basin; Populations with short distances presented low differentiation.

Salix viminalis L. is an important shrub that has potential for use as a bioenergy crop, for phytoremediation of heavy metal contaminated soil and sewage sludge treatment. It is mainly distributed in the northeast of China, but the species has not yet been used a resource here. We examined the genetic diversity and population structure of populations from the Ergun basin and West Liao basin using 20 microsatellite markers. A high level of genetic diversity (Na = 16.45, He = 0.742) was detected for S. viminalis, and populations from the Ergun basin exhibited higher genetic diversity and private alleles numbers than the West Liao basin. The 12 populations could be divided into two clusters by both Bayesian analysis and UPGMA clustering which were consistent with the populations derived from the two basins. Moderate population differentiation (FST = 0.076) was shown in S. viminalis, and AMOVA analysis confirmed that most of the genetic variation (86.13%) was attributed to individual differences within populations, while 11.49% was attributed to differences between basins and 2.38% to differences within each basin. Significant correlations of FST/(1–FST) with log (geographic distance) among 12 populations (r = 0.634, p < 0.00) and 10 populations within the Ergun basin (r = 0.482, p = 0.0002) indicated that geographical distance was the principal factor influencing genetic structure. As most of genetic variation exist within populations, so protection measures should be focused on populations with higher genetic diversity and unique alleles, such as Tuli, Mordaga downstream, Zhadun1 and Genhe.

  • Zhai, State Key Laboratory of Tree Genetics and Breeding; Research Institute of Forestry, Chinese Academy of Forestry; Key Laboratory of Tree Breeding and Cultivation, State Forestry Administration, Haidian District, Beijing, 10091, PR China; School of Architectural and Artistic Design, Henan Polytechnic University, Century Avenue, Jiaozuo, Henan, 454000, PR China ORCID ID:E-mail: lkyzff@163.com
  • Liu, State Key Laboratory of Tree Genetics and Breeding; Research Institute of Forestry, Chinese Academy of Forestry; Key Laboratory of Tree Breeding and Cultivation, State Forestry Administration, Haidian District, Beijing, 10091, PR China ORCID ID:E-mail: liu-jx295@163.com
  • Li, State Key Laboratory of Tree Genetics and Breeding; Research Institute of Forestry, Chinese Academy of Forestry; Key Laboratory of Tree Breeding and Cultivation, State Forestry Administration, Haidian District, Beijing, 10091, PR China ORCID ID:E-mail: zhenjianli@163.com
  • Mao, State Key Laboratory of Tree Genetics and Breeding; Research Institute of Forestry, Chinese Academy of Forestry; Key Laboratory of Tree Breeding and Cultivation, State Forestry Administration, Haidian District, Beijing, 10091, PR China; Research Institute of Economic Forest, Xinjiang Academy of Forestry, Anjunanlu, Urumqi, Xinjiang, PR China ORCID ID:E-mail: 350512173@qq.com
  • Qian, State Key Laboratory of Tree Genetics and Breeding; Research Institute of Forestry, Chinese Academy of Forestry; Key Laboratory of Tree Breeding and Cultivation, State Forestry Administration, Haidian District, Beijing, 10091, PR China ORCID ID:E-mail: qianyq@caf.ac.cn
  • Han, State Key Laboratory of Tree Genetics and Breeding; Research Institute of Forestry, Chinese Academy of Forestry; Key Laboratory of Tree Breeding and Cultivation, State Forestry Administration, Haidian District, Beijing, 10091, PR China ORCID ID:E-mail: hdd@caf.ac.cn
  • Sun, State Key Laboratory of Tree Genetics and Breeding; Research Institute of Forestry, Chinese Academy of Forestry; Key Laboratory of Tree Breeding and Cultivation, State Forestry Administration, Haidian District, Beijing, 10091, PR China ORCID ID:E-mail: lkyszy@126.com (email)
article id 5656, category Research article
Lars-Göran Stener, Johan Westin. (2017). Early growth and phenology of hybrid aspen and poplar in clonal field tests in Scandinavia. Silva Fennica vol. 51 no. 3 article id 5656. https://doi.org/10.14214/sf.5656
Highlights: Growth and survival was in general higher for hybrid aspen than for poplar; The poor performance of poplar was likely due to poor climatic adaptation or to high soil acidity; The genetic results indicate good possibilities for effective clonal selection; The results support current recommendations for utilization of selected hybrid aspen and poplar regeneration material in Sweden.

Results on early survival, growth and shoot phenology of hybrid aspen (Populus tremula L. × P. tremuloides Michx.) and poplar clones (P. trichocarpa Torr. & A. Gray, P. balsamifera L., P. maximowiczii A. Henry and their hybrids) in 13 Scandinavian field trials are presented. The trials were established on forest land (7 sites) or former agricultural land (6 sites) within the latitude range of 56° to 65° N and were assessed 3–4 years after establishment. The main aim was to evaluate phenotypic and genetic differences related to early survival, growth and phenology for hybrid aspen and poplar for different site types and latitudes. Growth and survival was generally higher for hybrid aspen than poplar at all sites. The poor performance of poplar compared to hybrid aspen is likely due to climatic maladaptation or high soil acidity. The early growth performance of the species need to be confirmed at a higher age. The genetic variation and genetic control for growth, phenology and survival was in general intermediate to large indicating good possibilities for effective clonal selection. The genetic site x site correlations (rGE) for growth were for hybrid aspen mostly strong, indicating a weak genotype by environment interaction, while rGE were inconsistent for poplars.The result suggests that southern Sweden can be treated as a single test and utilization zone and in northern Sweden the region along the coast may be another zone. It is too early to make any corresponding conclusions for poplar. In addition, the result backs up the current recommendations for utilization of selected hybrid aspen and poplar regeneration material in Sweden.

  • Stener, The Forestry Research Institute of Sweden, Ekebo 2250, 268 90 Svalöv, Sweden ORCID ID:E-mail: lars-goran.stener@skogforsk.se (email)
  • Westin, The Forestry Research Institute of Sweden, Box 3, 918 21 Sävar, Sweden ORCID ID:E-mail: johan.westin@skogforsk.se
article id 1743, category Research article
Gintare Sabalinkiene, Darius Danusevicius, Michael Manton, Gediminas Brazaitis, Kastytis Simkevicius. (2017). Differentiation of European roe deer populations and ecotypes in Lithuania based on DNA markers, cranium and antler morphometry. Silva Fennica vol. 51 no. 3 article id 1743. https://doi.org/10.14214/sf.1743
Highlights: Lithuanian roe deer populations are genetically structured into southern and northern groups, most likely affected by a divergent gene flow and Lithuania’s largest rivers slowing down migration; Microsatellite and skull morphology based genetic differentiation between field and forest ecotypes are weak; Geographical location has a significant effect on antler morphometry traits and skull size of male roe deer, the latter increasing northwards.

The objective of our study was to assess the genetic and morphological differentiation of European roe deer (Capreolus capreolus L.) in Lithuania based on DNA markers, skull and anther morphology. DNA was extracted from 79 culled individuals at 13 locations and genotyped at five nuclear microsatellite loci. Based on culling location, individuals were assigned to either a field (N = 43) or a forest ecotype (N = 36). Skull and antler morphometry was studied on 603 and 292 individuals, respectively. Results showed no significant genetic and skull morphology differentiation between the ecotypes. The forest ecotype tends to exhibit lower genetic diversity compared to the field ecotype, particularly for male individuals. The genetic differentiation of roe deer in Lithuania was significant based on the RST values, but not on the FST values. A STRUCTURE analyses revealed southern and northern genetic clusters, most likely affected by divergent gene flow. The country’s major rivers Nemunas and Neris are likely to increase differentiation between the clusters. ANOVA on skull morphology by gender and age indicated a significant effect of geographical location. Skull size (especially length) is greater in the northern part of the country. We also found significant effects of age, ecotype and geographical location on most of the roe deer male antler morphometric traits.

  • Sabalinkiene, Institute of Forest Biology and Silviculture, Faculty of Forest Sciences and Ecology, Aleksandras Stulginskis University, Studentu street 11, Akademija, Kaunas district, Lithuania ORCID ID:E-mail: gintare.sabalinkiene@asu.lt (email)
  • Danusevicius, Institute of Forest Biology and Silviculture, Faculty of Forest Sciences and Ecology, Aleksandras Stulginskis University, Studentu street 11, Akademija, Kaunas district, Lithuania ORCID ID:E-mail: darius.danusevicius@asu.lt
  • Manton, Institute of Forest Biology and Silviculture, Faculty of Forest Sciences and Ecology, Aleksandras Stulginskis University, Studentu street 11, Akademija, Kaunas district, Lithuania ORCID ID:E-mail: michael.manton@asu.lt
  • Brazaitis, Institute of Forest Biology and Silviculture, Faculty of Forest Sciences and Ecology, Aleksandras Stulginskis University, Studentu street 11, Akademija, Kaunas district, Lithuania ORCID ID:E-mail: gediminas.brazaitis@asu.lt
  • Simkevicius, Institute of Forest Biology and Silviculture, Faculty of Forest Sciences and Ecology, Aleksandras Stulginskis University, Studentu street 11, Akademija, Kaunas district, Lithuania ORCID ID:E-mail: kastytis.simkevicius@asu.lt
article id 2021, category Research article
Jonas Bohlin, Inka Bohlin, Jonas Jonzén, Mats Nilsson. (2017). Mapping forest attributes using data from stereophotogrammetry of aerial images and field data from the national forest inventory. Silva Fennica vol. 51 no. 2 article id 2021. https://doi.org/10.14214/sf.2021
Highlights: Image based forest attribute map generated using NFI plots show similar accuracy as currently used LiDAR based forest attribute map; Also similar accuracies were found for different forest types; Aerial images from leaf-off season is not recommended.

Exploring the possibility to produce nation-wide forest attribute maps using stereophotogrammetry of aerial images, the national terrain model and data from the National Forest Inventory (NFI). The study areas are four image acquisition blocks in mid- and south Sweden. Regression models were developed and applied to 12.5 m × 12.5 m raster cells for each block and validation was done with an independent dataset of forest stands. Model performance was compared for eight different forest types separately and the accuracies between forest types clearly differs for both image- and LiDAR methods, but between methods the difference in accuracy is small at plot level. At stand level, the root mean square error in percent of the mean (RMSE%) were ranging: from 7.7% to 10.5% for mean height; from 12.0% to 17.8% for mean diameter; from 21.8% to 22.8% for stem volume; and from 17.7% to 21.1% for basal area. This study clearly shows that aerial images from the national image program together with field sample plots from the NFI can be used for large area forest attribute mapping.

  • Bohlin, Department of Forest Resource Management, Swedish University of Agricultural Sciences, S-901 35 Umeå, Sweden ORCID ID: http://orcid.org/0000-0002-3318-5967 E-mail: jonas.bohlin@slu.se (email)
  • Bohlin, Department of Forest Resource Management, Swedish University of Agricultural Sciences, S-901 35 Umeå, Sweden ORCID ID: http://orcid.org/0000-0003-1224-6684 E-mail: inka.bohlin@slu.se
  • Jonzén, Department of Forest Resource Management, Swedish University of Agricultural Sciences, S-901 35 Umeå, Sweden ORCID ID:E-mail: jonas.jonzen@slu.se
  • Nilsson, Department of Forest Resource Management, Swedish University of Agricultural Sciences, S-901 35 Umeå, Sweden ORCID ID: http://orcid.org/0000-0001-7394-6305 E-mail: mats.nilsson@slu.se
article id 1721, category Research article
Anna Hebda, Błażej Wójkiewicz, Witold Wachowiak. (2017). Genetic characteristics of Scots pine in Poland and reference populations based on nuclear and chloroplast microsatellite markers. Silva Fennica vol. 51 no. 2 article id 1721. https://doi.org/10.14214/sf.1721
Highlights: Similar genetic variation was found between Polish Scots pine populations from a wide variety of habitats based on nSSR and cpSSR markers; Homogeneity was observed in the genetic structures of Polish and Finnish populations from the continuous pine range; Genetic differentiation in microsatellite markers was identified only when populations from the central pine distribution were compared to the marginal stands.

Polymorphisms at a set of eighteen nuclear (nSSR) and chloroplast (cpSSR) microsatellite loci were investigated in sixteen populations of Scots pine (Pinus sylvestris L.) derived from the provenance trial experiment and representative of the species distribution range and climatic zones in Poland. The patterns of genetic variation were compared to the reference samples from the species distribution in Europe and Asia. A similar level of genetic variation and no evidence of population structure was found among the Polish stands. They showed genetic similarity and homogenous patterns of allelic frequency spectra compared to the Northern European populations. Those populations were genetically divergent compared to the marginal populations from Turkey, Spain and Scotland. The population structure patterns reflect the phylogeography of the species and the divergence of populations that most likely do not share recent history. As the analysed provenance trial populations from Poland are diverged in phenotypic traits but are genetically similar, they could be used to test for selection at genomic regions that influence variation in quantitative traits.

  • Hebda, University of Agriculture in Krakow, Faculty of Forestry, Institute of Forest Ecology and Silviculture, Department of Genetics and Forest Tree Breeding, 29 Listopada 46, 31-425 Kraków, Poland ORCID ID: http://orcid.org/0000-0002-3149-8644 E-mail: ana.hebda@gmail.com (email)
  • Wójkiewicz, Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland ORCID ID:E-mail: bwojkiew@man.poznan.pl
  • Wachowiak, Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland; Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland ORCID ID:E-mail: witoldw@man.poznan.pl
article id 1684, category Research article
Anna Kowalska, Jan Marek Matuszkiewicz, Jerzy Solon, Anna Kozłowska. (2017). Indicators of ancient forests in nutrient-deficient pine habitats. Silva Fennica vol. 51 no. 1 article id 1684. https://doi.org/10.14214/sf.1684
Highlights: Distinct groups of species with a preference for ancient pine and mixed oak-pine forests can be determined; The ancient forest indicator composition in pine habitats differs remarkably from ancient forest indicators in deciduous forests; Dispersal-related traits significantly distinguish ancient forest indicators from other species found in nutrient-poor forest habitats.

Pine forests are common in many European regions. Nonetheless, there are only a few studies on regeneration of plant species populations in nutrient-deficient pine habitats. Ancient temperate forests are perceived to be particularly important objects of environmental conservation, due to their ability to sustain a considerable number of rare and vulnerable species. In this paper, we present indicator species of ancient pine and mixed oak-pine forests, together with their trait profiles. Phytosociological relevés were collected from mature stands in the Masuria and Kurpie regions of central Poland. Forest persistence was determined on the basis of historical maps, with the data set divided into three categories. The indicator value of species was evaluated using Tichý and Chytrý’s phi coefficient. Functional response traits of indicator species were identified. Distinct groups of species with a preference for ancient forests can be determined. The dispersal-related traits significantly distinguish ancient forest indicators from other species found in nutrient-poor forest habitats. Since the low potential for long-distance dispersal hinders the establishment of new plant populations in isolated stands, we stress the need to avoid ancient forest clearance and fragmentation of woodland; afforestation should be located in the vicinity of ancient stands. Moreover, as recent forests have turned out to support several rare plant species, to maintain phytodiversity on a landscape level a mixture of ancient and recent forests, both managed and strictly protected, is needed.

  • Kowalska, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: aniak@twarda.pan.pl (email)
  • Matuszkiewicz, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: jan.mat@twarda.pan.pl
  • Solon, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: j.solon@twarda.pan.pl
  • Kozłowska, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: a.kozl@twarda.pan.pl
article id 1566, category Research article
Valdir Marcos Stefenon, Jordana Caroline Nagel, Igor Poletto. (2016). Evidences of genetic bottleneck and fitness decline in Luehea divaricata populations from southern Brazil. Silva Fennica vol. 50 no. 5 article id 1566. https://doi.org/10.14214/sf.1566
Highlights: Signatures of genetic bottlenecks and reduction of populations’ fitness were observed in populations of Luehea divaricata in southern Brazil; Lower levels of observed heterozygosity are correlated with populations’ fitness, decreasing germination capacity and increasing the proportion of anomalous germinated plantlets; Promoting the connection among populations is proposed as a key strategy towards conservation of L. divaricata genetic resources in its southernmost distribution range.

Extant populations growing in regions that were refugia during the last glacial period are expected to show higher genetic diversity than populations that moved from these refugia into new areas in higher latitudes. Such new populations likely faced harsher climatic conditions, being established with reduced population size and experiencing the effects of genetic bottlenecks. In this study we employed data from nuclear SSR markers for detecting molecular signatures of genetic bottlenecks, and germination experiments to evaluate reduction of populations’ fitness in natural populations of Luehea divaricata Mart. et Zucc., growing in the southern range of the species distribution (around 30°S latitude). Signatures of genetic bottlenecks and reduction of populations’ fitness were observed in all populations. Lower levels of observed heterozygosity are correlated with populations’ fitness, decreasing germination capacity and increasing the proportion of anomalous germinated plantlets. Promoting the connection among populations is proposed as a key strategy towards conservation of L. divaricata genetic resources in its southernmost distribution range. The offspring from crosses among populations would significantly increase the observed heterozygosity and fitness of multiple populations.

  • Stefenon, Nucleus of Genomics and Molecular Ecology, Interdisciplinary Center of Biotechnological Research, Universidade Federal do Pampa, BR290 km, 97300-000, São Gabriel, RS, Brazil ORCID ID:E-mail: valdirstefenon@unipampa.edu.br (email)
  • Nagel, Nucleus of Genomics and Molecular Ecology, Interdisciplinary Center of Biotechnological Research, Universidade Federal do Pampa, BR290 km, 97300-000, São Gabriel, RS, Brazil ORCID ID:E-mail: jordana.nagel@yahoo.com.br
  • Poletto, Laboratory of Plant Protection, Universidade Federal do Pampa, BR290 km, 97300-000, São Gabriel, RS, Brazil ORCID ID:E-mail: igorpoletto@unipampa.edu.br
article id 1565, category Research article
Teija Ruuhola, Ari Nikula, Nivala Vesa, Seppo Nevalainen, Juho Matala. (2016). Effects of bedrock and surficial deposit composition on moose damage in young forest stands in Finnish Lapland. Silva Fennica vol. 50 no. 3 article id 1565. https://doi.org/10.14214/sf.1565
Highlights: The effect of bedrock and soil on moose damage in forest plantations were examined; Moose damage were concentrated in nutrient rich bedrock areas; Bedrock of damaged stands contained a higher proportion of mafic and alkaline rocks; Pine-dominated stands on fine grained fertile forest sites had the highest damage risk.

There is evidence that moose are attracted to fertile growth habitats apparently due to better quality and larger quantities of food. The nutrients in mineral soils originate from the weathering of bedrock and the composition of parental bedrock affects the fertility of produced mineral soil, thus affecting also the import of nutrients into the whole food web. We surveyed the connection between moose damage in forest plantations and the composition of bedrock and surficial deposits in Finnish Lapland. We used a database of compensated moose damage in private forests in years 1997−2010. Undamaged stands in National Forest Inventories (NFI) from years 1986–2008 served as a control data and moose-damaged NFI-stands as a reference data. Bedrock and surficial depositions and the location of studied stands in relation to ancient shorelines were explored by using the digital databases of the Geological Survey of Finland. Moose-damaged stands were concentrated in southwestern and east Lapland in the areas of the Peräpohja Schist Belt and Lapland’s Greenstone Belt that are both composed of nutrient-rich rocks. The bedrock of damaged stands contained a higher proportion of mafic and alkaline rocks than did the control stands. Moose-damaged stands were pine-dominated and grew in more fertile forest sites than did control stands. Part of pine stands probably located in soils formerly occupied by spruce, which may increase the stands’ vulnerability to biotic threats. Especially, there were relatively more moose damage in pine plantations regenerated on fine-grained mineral soils derived from nutrient rich rocks than in less fertile soils.

  • Ruuhola, Natural Resources Institute Finland (Luke), Natural Resources and Bioproduction, Yliopistokatu 6, FI-80101 Joensuu, Finland; University of Eastern Finland, Faculty of Science and Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: teija.ruuhola@uef.fi
  • Nikula, Natural Resources Institute Finland (Luke), Economics and Society, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: ari.nikula@luke.fi (email)
  • Vesa, Natural Resources Institute Finland (Luke), Economics and Society, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: vesa.nivala@luke.fi
  • Nevalainen, Natural Resources Institute Finland (Luke), Natural Resources and Bioproduction, Yliopistokatu 6, FI-80101 Joensuu, Finland ORCID ID:E-mail: seppo.nevalainen@luke.fi
  • Matala, Natural Resources Institute Finland (Luke), Natural Resources and Bioproduction, Yliopistokatu 6, FI-80101 Joensuu, Finland ORCID ID:E-mail: juho.matala@luke.fi
article id 1560, category Research article
Marina Gurskaya, Pavel Moiseev, Martin Wilmking. (2016). Does slope exposure affect frost ring formation in Picea obovata growing at treeline in the Southern Urals? Silva Fennica vol. 50 no. 3 article id 1560. https://doi.org/10.14214/sf.1560
Highlights: Frost ring formation was ubiquitous from continuous forest cover to treeline, but, surprisingly, was not affected by slope exposure; Late frosts in spring were the main cause for frost ring formation; While mainly young trees (< 30 years) recorded frost events, at the climatically harshest site (highest elevation, northeastern exposure), frost events were recorded also in trees older than 70 years.

Topographic complexity in mountainous ecosystems strongly influences plant growth and as such also wood formation. This wood formation can possibly be used to understand topographic variation of the main climatic drivers, e.g. by modulating frost events. Here we test the influence of different slope exposures on the spatio-temporal distribution of frost rings in Siberian spruce (Picea obovata Ledeb.) in the Southern Urals, Russia. We sampled on two opposite slopes, northeast (NE) and southwest (SW), on three elevation levels from the highest single trees to closed canopy forest and analysed frost ring occurrence and their seasonal timing. Frost ring formation at all exposure-elevation combinations was common and mainly concentrated in the early part of the growing season. The age until trees record frost rings was equally similar (until about 35 years) on both slopes and different elevational levels with the exception of the climatically harshest site, the highest elevation on the NE slope. While we could not deduce a direct, easily identifiable climatic driver for the formation of frost rings, our analysis shows high potential to disentangle the complex interplay between climate, site condition and tree growth in mountainous ecosystems.

  • Gurskaya, Institute of Plant and Animal Ecology (IPAE), Ural Branch of Russian Academy of Sciences , 8 Marta St. 202, 620144 Ekaterinburg, Russia ORCID ID:E-mail: mgurskaya@yandex.ru (email)
  • Moiseev, Institute of Plant and Animal Ecology (IPAE), Ural Branch of Russian Academy of Sciences , 8 Marta St. 202, 620144 Ekaterinburg, Russia ORCID ID:E-mail: moiseev@ipae.uran.ru
  • Wilmking, Institute of Botany and Landscape Ecology, Soldmanstrasse 15, Ernst-Moritz-Arndt-University Greifswald, 17487 Greifswald, Germany ORCID ID:E-mail: wilmking@uni-greifswald.de
article id 1413, category Research article
Ilya Potapov, Marko Järvenpää, Markku Åkerblom, Pasi Raumonen, Mikko Kaasalainen. (2016). Data-based stochastic modeling of tree growth and structure formation. Silva Fennica vol. 50 no. 1 article id 1413. https://doi.org/10.14214/sf.1413
Highlights: We propose a stochastic version of the tree growth model LIGNUM for producing tree structures consistent with detailed terrestrial laser scanning data, and we provide the proof-of-concept by using model-based simulations and real laser scanning data; Trees produced with the data-based model resemble the trees of the dataset, and are statistically similar but not copies of each other; the number of such synthetic trees is not limited.

We introduce a general procedure to match a stochastic functional-structural tree model (here LIGNUM augmented with stochastic rules) with real tree structures depicted by quantitative structure models (QSMs) based on terrestrial laser scanning. The matching is done by iteratively finding the maximum correspondence between the measured tree structure and the stochastic choices of the algorithm. First, we analyze the match to synthetic data (generated by the model itself), where the target values of the parameters to be estimated are known in advance, and show that the algorithm converges properly. We then carry out the procedure on real data obtaining a realistic model. We thus conclude that the proposed stochastic structure model (SSM) approach is a viable solution for formulating realistic plant models based on data and accounting for the stochastic influences.

  • Potapov, Tampere University of Technology, Department of Mathematics, P.O. Box 553, FI-33101 Tampere, Finland ORCID ID:E-mail: ilya.potapov@tut.fi (email)
  • Järvenpää, Tampere University of Technology, Department of Mathematics, P.O. Box 553, FI-33101 Tampere, Finland ORCID ID:E-mail: marko.jarvenpaa@tut.fi
  • Åkerblom, Tampere University of Technology, Department of Mathematics, P.O. Box 553, FI-33101 Tampere, Finland ORCID ID:E-mail: markku.akerblom@tut.fi
  • Raumonen, Tampere University of Technology, Department of Mathematics, P.O. Box 553, FI-33101 Tampere, Finland ORCID ID:E-mail: pasi.raumonen@tut.fi
  • Kaasalainen, Tampere University of Technology, Department of Mathematics, P.O. Box 553, FI-33101 Tampere, Finland ORCID ID:E-mail: mikko.kaasalainen@tut.fi
article id 1348, category Research article
Sakari Tuominen, Andras Balazs, Heikki Saari, Ilkka Pölönen, Janne Sarkeala, Risto Viitala. (2015). Unmanned aerial system imagery and photogrammetric canopy height data in area-based estimation of forest variables. Silva Fennica vol. 49 no. 5 article id 1348. https://doi.org/10.14214/sf.1348
Highlights: Orthoimage mosaic and 3D canopy height model were derived from UAV-borne colour-infrared digital camera imagery and ALS-based terrain model; Features extracted from orthomosaic and canopy height data were used for estimating forest variables; The accuracy of forest estimates was similar to that of the combination of ALS and digital aerial imagery.

In this paper we examine the feasibility of data from unmanned aerial vehicle (UAV)-borne aerial imagery in stand-level forest inventory. As airborne sensor platforms, UAVs offer advantages cost and flexibility over traditional manned aircraft in forest remote sensing applications in small areas, but they lack range and endurance in larger areas. On the other hand, advances in the processing of digital stereo photography make it possible to produce three-dimensional (3D) forest canopy data on the basis of images acquired using simple lightweight digital camera sensors. In this study, an aerial image orthomosaic and 3D photogrammetric canopy height data were derived from the images acquired by a UAV-borne camera sensor. Laser-based digital terrain model was applied for estimating ground elevation. Features extracted from orthoimages and 3D canopy height data were used to estimate forest variables of sample plots. K-nearest neighbor method was used in the estimation, and a genetic algorithm was applied for selecting an appropriate set of features for the estimation task. Among the selected features, 3D canopy features were given the greatest weight in the estimation supplemented by textural image features. Spectral aerial photograph features were given very low weight in the selected feature set. The accuracy of the forest estimates based on a combination of photogrammetric 3D data and orthoimagery from UAV-borne aerial imaging was at a similar level to those based on airborne laser scanning data and aerial imagery acquired using purpose-built aerial camera from the same study area.

  • Tuominen, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: sakari.tuominen@luke.fi (email)
  • Balazs, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: andras.balazs@luke.fi
  • Saari, VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FI-02044 VTT, Finland ORCID ID:E-mail: Heikki.Saari@vtt.fi
  • Pölönen, University of Jyväskylä, Department of Mathematical Information Technology, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: ilkka.polonen@jyu.fi
  • Sarkeala, Mosaicmill Oy, Kultarikontie 1, FI-01300 Vantaa, Finland ORCID ID:E-mail: janne.sarkeala@mosaicmill.com
  • Viitala, Häme University of Applied Sciences (HAMK), P.O. Box 230, FI-13101 Hämeenlinna, Finland ORCID ID:E-mail: Risto.Viitala@hamk.fi
article id 1328, category Research article
Nelly N. Selochnik, Nataliya V. Pashenova, Evgeny Sidorov, Michael J. Wingfield, Riikka Linnakoski. (2015). Ophiostomatoid fungi and their roles in Quercus robur die-back in Tellermann forest, Russia. Silva Fennica vol. 49 no. 5 article id 1328. https://doi.org/10.14214/sf.1328
Highlights: Dominant ophiostomatoid fungi associated with Q. robur in the post-outbreak region of oak die-back were investigated; Ophiostoma quercus was the most commonly encountered fungus; This is the first report of O. grandicarpum from Russia; The results of preliminary pathogenicity experiments demonstrate that fungi investigated in this study are unlikely to play causal role in oak die-back

Several eastern European countries have reported outbreaks of oak die-back during the 1980’s. Species of Ophiostoma Syd. were isolated from diseased trees and have been suggested to be the possible causal agents of the die-back, but this view have generally not been accepted. In order to monitor the post-outbreak region of oak die-back and to consider the possible role of Ophiostoma spp. in the syndrome, research has been conducted in the Tellerman forest, Voronezh region, Russia between 2005 and 2011. Our study resulted in the isolation of ophiostomatoid fungi from Quercus robur L. trees displaying external signs of desiccation. Fungi were identified based on morphological characteristics and DNA sequence comparisons. Three species of Ophiostoma were identified including O. grandicarpum (Kowalski & Butin) Rulamort, a species closely related to O. abietinum Marm. & Butin, O. fusiforme Aghayeva & M.J. Wingf. and O. lunatum Aghayeva & M.J. Wingf. representing a poorly understood species complex, and most commonly O. quercus (Georgev.) Nannf. Pathogenicity of these fungi was tested using artificial inoculations on Q. robur trees. The fungi were shown to be non-pathogenic and unlikely to play any role in oak die-back. These fungi are most likely only components in a complex of abiotic, biotic and anthropogenic factors that have contributed to a die-back of Quercus spp. in Russia.

  • Selochnik, Forest Science Institute of RAS, Uspenskoe 143030, Moscow Region, Russia ORCID ID:E-mail: lenelse@yandex.ru
  • Pashenova, V.N. Sukachev Institute of Forest SB RAS, Krasnoyarsk 660036, Russia ORCID ID:E-mail: pasnat@ksc.krasn.ru
  • Sidorov, Department of Forest Protection and Game Management, St. Petersburg State Forest Technical University, St. Petersburg 194021, Russia ORCID ID:E-mail: sidorov_evgeny@mail.ru
  • Wingfield, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, 0002 Pretoria, South Africa ORCID ID:E-mail: mike.wingfield@up.ac.za
  • Linnakoski, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, 0002 Pretoria, South Africa; Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID: http://orcid.org/0000-0002-3294-8088 E-mail: riikka.linnakoski@helsinki.fi (email)
article id 1328, category Research article
Nelly N. Selochnik, Nataliya V. Pashenova, Evgeny Sidorov, Michael J. Wingfield, Riikka Linnakoski. (2015). Ophiostomatoid fungi and their roles in Quercus robur die-back in Tellermann forest, Russia. Silva Fennica vol. 49 no. 5 article id 1328. https://doi.org/10.14214/sf.1328
Highlights: Dominant ophiostomatoid fungi associated with Q. robur in the post-outbreak region of oak die-back were investigated; Ophiostoma quercus was the most commonly encountered fungus; This is the first report of O. grandicarpum from Russia; The results of preliminary pathogenicity experiments demonstrate that fungi investigated in this study are unlikely to play causal role in oak die-back

Several eastern European countries have reported outbreaks of oak die-back during the 1980’s. Species of Ophiostoma Syd. were isolated from diseased trees and have been suggested to be the possible causal agents of the die-back, but this view have generally not been accepted. In order to monitor the post-outbreak region of oak die-back and to consider the possible role of Ophiostoma spp. in the syndrome, research has been conducted in the Tellerman forest, Voronezh region, Russia between 2005 and 2011. Our study resulted in the isolation of ophiostomatoid fungi from Quercus robur L. trees displaying external signs of desiccation. Fungi were identified based on morphological characteristics and DNA sequence comparisons. Three species of Ophiostoma were identified including O. grandicarpum (Kowalski & Butin) Rulamort, a species closely related to O. abietinum Marm. & Butin, O. fusiforme Aghayeva & M.J. Wingf. and O. lunatum Aghayeva & M.J. Wingf. representing a poorly understood species complex, and most commonly O. quercus (Georgev.) Nannf. Pathogenicity of these fungi was tested using artificial inoculations on Q. robur trees. The fungi were shown to be non-pathogenic and unlikely to play any role in oak die-back. These fungi are most likely only components in a complex of abiotic, biotic and anthropogenic factors that have contributed to a die-back of Quercus spp. in Russia.

  • Selochnik, Forest Science Institute of RAS, Uspenskoe 143030, Moscow Region, Russia ORCID ID:E-mail: lenelse@yandex.ru
  • Pashenova, V.N. Sukachev Institute of Forest SB RAS, Krasnoyarsk 660036, Russia ORCID ID:E-mail: pasnat@ksc.krasn.ru
  • Sidorov, Department of Forest Protection and Game Management, St. Petersburg State Forest Technical University, St. Petersburg 194021, Russia ORCID ID:E-mail: sidorov_evgeny@mail.ru
  • Wingfield, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, 0002 Pretoria, South Africa ORCID ID:E-mail: mike.wingfield@up.ac.za
  • Linnakoski, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, 0002 Pretoria, South Africa; Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID: http://orcid.org/0000-0002-3294-8088 E-mail: riikka.linnakoski@helsinki.fi (email)
article id 1310, category Research article
Deliang Lu, Jiaojun Zhu, Yirong Sun, Lile Hu, Guangqi Zhang. (2015). Gap closure process by lateral extension growth of canopy trees and its effect on woody species regeneration in a temperate secondary forest, Northeast China. Silva Fennica vol. 49 no. 5 article id 1310. https://doi.org/10.14214/sf.1310
Highlights: Gap closure process by lateral extension growth can be described by quadratic functions; Large gaps (514–621 m2) had higher closure rates but lower closure percentages compared with middle (174–321 m2) and small gaps (68–125 m2); Gaps promoted woody species regeneration in early stage; Large and middle gaps would provide opportunities for filling regeneration, but regeneration in small gaps may eventually fail.

Gap formation and its effects on regeneration have been reported as being important in forest development, but seldom studies concentrated on the gap closure process by lateral extension growth of canopy trees surrounding gaps. We monitored the closure process of 12 artificial gaps for 7 years with three size classes: small (from 68 m2 to 125 m2), middle (from 174 m2 to 321 m2), and large (from 514 m2 to 621 m2); and investigated the regeneration twice in a temperate secondary forest, Northeast China. The closure process can be described through quadratic functions, which showed the closure rates slowed down with gap ages. Large gaps had a higher closure rate (39 m2 a–1) than middle gaps (25 m2 a–1) and small gaps (11 m2 a–1). According to the quadratic equations, the lateral growth could last 11, 13 and 16 years for small, middle and large gaps with a remaining size of 12, 69 and 223 m2, respectively. As expected, regeneration exhibited the highest seedling density and volume in large gaps. There was no significant difference in regeneration density between middle gaps, small gaps and forest understory in the final investigation; but the volume of regenerated woody species increased significantly from small gaps to large gaps compared with forest understory. These results may provide references on the choice of appropriate gap sizes to promote the regeneration in temperate secondary forests.

  • Lu, State Key Laboratory of Forest and Soil Ecology, Qingyuan Forest CERN, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China;  University of Chinese Academy of Sciences, Beijing 100049, China ORCID ID:E-mail: delianglu14@hotmail.com
  • Zhu, State Key Laboratory of Forest and Soil Ecology, Qingyuan Forest CERN, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China ORCID ID:E-mail: jiaojunzhu@iae.ac.cn (email)
  • Sun, State Key Laboratory of Forest and Soil Ecology, Qingyuan Forest CERN, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China ORCID ID:E-mail: yirongsun@iae.ac.cn
  • Hu,  Chinese Research Academy of Environmental Sciences, Beijing 100012, China ORCID ID:E-mail: lilehu@gmail.com
  • Zhang, State Key Laboratory of Forest and Soil Ecology, Qingyuan Forest CERN, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China;  University of Chinese Academy of Sciences, Beijing 100049, China ORCID ID:E-mail: zgq04713@163.com
article id 1056, category Research article
Katri Himanen, Markku Nygren. (2015). Seed soak-sorting prior to sowing affects the size and quality of 1.5-year-old containerized Picea abies seedlings. Silva Fennica vol. 49 no. 3 article id 1056. https://doi.org/10.14214/sf.1056
Highlights: After soak-sorting all sunken seeds (bottom fraction) were full and viable, whereas floating seeds contained larvae-filled and immature seed; Seedlings originating from the bottom fraction were greater in height and diameter than control seedlings or those originating from the floating seeds; The proportion of saleable seedlings was four percentage points higher in the bottom fraction than in the other seedlings.

We studied the effect of soak-sorting Norway spruce (Picea abies (L.) H. Karst.) seeds on emergence, development and quality of container seedlings in two commercial seed lots. The seeds, separated by soaking into bottom and surface fractions, were sown in June, and the seedlings were grown during two growing seasons under typical Finnish nursery conditions. The first summer seedlings were grown in a greenhouse and outdoors for the second, full growing season. All sunken seeds were full and viable according to radiography, whereas the floating seeds contained 2% and 13% larvae-filled and 8% and 11% anatomically immature seeds, depending on the seed lot. Seedlings grown from the bottom fraction seed emerged 2.5–3.5 days earlier than seedlings of storage dry (i.e. control) seed. Height, diameter, and shoot and root dry mass of the seedlings were affected by soaking after both the first and second growing seasons. The largest seedlings originated from the bottom fraction. The proportion of saleable seedlings was four percentage points higher in the bottom fraction than in the other seedlings. The effects of soaking found in this study are more notable than as previously reported for Norway spruce seedlings. This suggests that soaking and soak-sorting may be most useful when the growing conditions are stressful, i.e. when seeds are sown in summer rather than 1-year-old seedling crops sown in spring under the climate conditions typical of Finland.

  • Himanen, Natural Resources Institute Finland (Luke), Green technology, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: katri.himanen@luke.fi (email)
  • Nygren, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: markku.nygren@luke.fi
article id 1056, category Research article
Katri Himanen, Markku Nygren. (2015). Seed soak-sorting prior to sowing affects the size and quality of 1.5-year-old containerized Picea abies seedlings. Silva Fennica vol. 49 no. 3 article id 1056. https://doi.org/10.14214/sf.1056
Highlights: After soak-sorting all sunken seeds (bottom fraction) were full and viable, whereas floating seeds contained larvae-filled and immature seed; Seedlings originating from the bottom fraction were greater in height and diameter than control seedlings or those originating from the floating seeds; The proportion of saleable seedlings was four percentage points higher in the bottom fraction than in the other seedlings.

We studied the effect of soak-sorting Norway spruce (Picea abies (L.) H. Karst.) seeds on emergence, development and quality of container seedlings in two commercial seed lots. The seeds, separated by soaking into bottom and surface fractions, were sown in June, and the seedlings were grown during two growing seasons under typical Finnish nursery conditions. The first summer seedlings were grown in a greenhouse and outdoors for the second, full growing season. All sunken seeds were full and viable according to radiography, whereas the floating seeds contained 2% and 13% larvae-filled and 8% and 11% anatomically immature seeds, depending on the seed lot. Seedlings grown from the bottom fraction seed emerged 2.5–3.5 days earlier than seedlings of storage dry (i.e. control) seed. Height, diameter, and shoot and root dry mass of the seedlings were affected by soaking after both the first and second growing seasons. The largest seedlings originated from the bottom fraction. The proportion of saleable seedlings was four percentage points higher in the bottom fraction than in the other seedlings. The effects of soaking found in this study are more notable than as previously reported for Norway spruce seedlings. This suggests that soaking and soak-sorting may be most useful when the growing conditions are stressful, i.e. when seeds are sown in summer rather than 1-year-old seedling crops sown in spring under the climate conditions typical of Finland.

  • Himanen, Natural Resources Institute Finland (Luke), Green technology, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: katri.himanen@luke.fi (email)
  • Nygren, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: markku.nygren@luke.fi
article id 1107, category Research article
Arvo Tullus, Arne Sellin, Priit Kupper, Reimo Lutter, Linnar Pärn, Anna K. Jasinska, Meeli Alber, Maarja Kukk, Tea Tullus, Hardi Tullus, Krista Lõhmus, Anu Sõber. (2014). Increasing air humidity – a climate trend predicted for northern latitudes – alters the chemical composition of stemwood in silver birch and hybrid aspen. Silva Fennica vol. 48 no. 4 article id 1107. https://doi.org/10.14214/sf.1107
Highlights: Hybrid aspen and silver birch trees grew more slowly under increased air humidity conditions and had higher concentrations of N and P and a lower K to N ratio in stemwood; Minor species-specific changes were detected in stemwood concentrations of cellulose and hemicellulose; Density, calorific value and concentrations of lignin and ash in stemwood were not affected by elevated humidity.
We studied the physicochemical properties of stemwood in saplings of silver birch (Betula pendula Roth) and hybrid aspen (Populus tremula L. × P. tremuloides Michx.), grown for four years under artificially elevated relative air humidity (on average by 7%) in field conditions, using the Free Air Humidity Manipulation (FAHM) research facility in Estonia. Altogether 91 sample trees from three experimental plots with manipulated air humidity and from three control plots were cut in the dormant season and sampled for the analysis of cellulose, hemicellulose, acid detergent lignin, macronutrients (N, P, K), ash content, density, and calorific value of wood. The analysed trees grew significantly more slowly under elevated humidity conditions, with a more pronounced effect on aspens. Significantly higher concentrations of N and P were observed in the stemwood of both aspens and birches grown under elevated humidity. This could be the result of a change in the content of living parenchyma cells and/or enhanced retranslocation of nutrients into wood parenchyma. Additionally, humidification resulted in a significantly higher concentration of cellulose and a lower concentration of hemicellulose in aspen stemwood, and in significantly lower concentrations of cellulose and K in birch stemwood. Elevated humidity did not affect lignin concentration, ash content, basic density and calorific value of stemwood. Results from the FAHM experiment suggest that the increasing air humidity accompanying global warming at northern latitudes will affect the growth and functioning of deciduous trees and forests, with obvious consequences also for forest management and industry.
  • Tullus, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: arvo.tullus@ut.ee (email)
  • Sellin, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: arne.sellin@ut.ee
  • Kupper, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: priit.kupper@ut.ee
  • Lutter, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: reimo.lutter@emu.ee
  • Pärn, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: linnar.parn@emu.ee
  • Jasinska, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia & Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland ORCID ID:E-mail: jasiak9@wp.pl
  • Alber, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: meeli.alber@ut.ee
  • Kukk, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: maarja.kukk@ut.ee
  • Tullus, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: tea.tullus@emu.ee
  • Tullus, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: hardi.tullus@emu.ee
  • Lõhmus, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: krista.lohmus@ut.ee
  • Sõber, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: anu.sober@ut.ee
article id 989, category Research article
Anna Saarsalmi, Pekka Tamminen, Mikko Kukkola. (2014). Effects of long-term fertilisation on soil properties in Scots pine and Norway spruce stands. Silva Fennica vol. 48 no. 1 article id 989. https://doi.org/10.14214/sf.989
Highlights: N fertilisation increased the amount of carbon in the organic layer; N fertilisation decreased the C/N ratio in the surface soil; N addition increased the amount of most nutrients in the organic layer; N fertilisation tended to lower pH, although only slightly.
The response of surface soil after 45- to 52-years to repeated nitrogen and phosphorus fertilisation was studied. This study included 30 factorial experiments established in young (5- to 30-year-old) stands using plots of 900 m2, on average, and by randomising treatments within each experiment. Total amount of N added varied from 534 to 1908 kg ha–1 and that of P from 69 to 193 kg ha–1, repeated at every second N fertilisation. Liming was performed twice; in total, 6000 kg ha–1 of dolomite was applied. Nitrogen fertilisation increased the mass of the organic layer and the amount of carbon and consequently the amounts of most of the elements in the organic layer. In both the organic layer and the 0–10 cm layer of mineral soil, nitrogen fertilisation decreased the C/N ratio and tended to lower pH, although only slightly. Phosphorus fertilisation increased the amounts of P and Ca. Liming increased the total amounts of most elements in the organic layer, except for C and N. We were able to derive models to describe how changes in the chemical properties of the surface soil depended on doses of elements and on site and stand properties.
  • Saarsalmi, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: anna.saarsalmi@metla.fi (email)
  • Tamminen, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: pekka.tamminen@metla.fi
  • Kukkola, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: mikko.kukkola@metla.fi
article id 1009, category Research article
Inger Sundheim Fløistad, Aksel Granhus. (2013). Timing and duration of short-day treatment influence morphology and second bud flush in Picea abies seedlings. Silva Fennica vol. 47 no. 3 article id 1009. https://doi.org/10.14214/sf.1009
Highlights: The duration of short-day treatment, calculated as number of days, influenced the root collar diameter growth more than the timing of the treatment; If short-day treatment starts early in summer, a longer duration of the treatment is recommended to avoid second bud flush.
A slower reaction of diameter growth cessation compared to that of height growth in response to short day (SD) treatment is well documented in Picea abies (L.) Karst. seedlings, suggesting that the height/diameter ratio of seedlings could be controlled through appropriate timing and/or duration of SD treatment is forest nurseries. Here, we applied specific combinations of timing (starting date 20 and 27 June, 4 or 11 July) and duration (7, 10, 14 or 17 days) of SD treatment to assess the possibility of obtaining more sturdy seedlings. We observed a rapid and uniform height growth cessation following SD treatment compared with the delayed cessation of diameter growth. Height growth responded significantly only to starting date of SD treatment, resulting in taller seedlings for later starting dates. Diameter growth responded to the duration of SD treatment, with significantly less diameter growth in seedlings exposed to 14 or 17 days of SD treatment than in seedlings exposed to 7 or 10 days of SD treatment. Also starting date influenced diameter growth, resulting in significantly more diameter growth with the earliest starting date compared with the two latest starting dates of the SD treatment.  A second bud flush occurred only in seedlings exposed to SD treatment starting on 20 or 27 of June and only following 7-14 days of duration. This implies a need of longer duration if the SD treatment starts early. This will be at the expense of sustained diameter growth, thus compromising the objective of obtaining more sturdy seedlings.
  • Fløistad, Norwegian Institute for Agricultural and Environmental Research, Høgskolevn 7, N-1430 Ås, Norway & Norwegian Forest and Landscape Institute, P.O. Box 115, N-1431 Ås, Norway ORCID ID:E-mail: isf@skogoglandskap.no (email)
  • Granhus, Norwegian Forest and Landscape Institute, P.O. Box 115, N-1431 Ås, Norway ORCID ID:E-mail: aksel.granhus@skogoglandskap.no
article id 970, category Research article
Zhen-Yu Du, Qing-Hua Wang, Shang-Jun Xing, Fang-Chun Liu, Bing-Yao Ma, Hai-Lin Ma, De-Xi Liu. (2013). Fine root distribution, characteristics and rhizosphere soil properties in a mixed stand of Robinia pseudoacacia and Fraxinus velutina in a saline soil. Silva Fennica vol. 47 no. 3 article id 970. https://doi.org/10.14214/sf.970
The spatial distribution and characteristics of fine roots (< 2 mm in diameter), and rhizosphere soil properties were studied in a mixed planted forest of black locust (Robinia pseudoacacia L.) and velvet ash (Fraxinus velutina Torr.) 27 years after planting in a coastal saline soil of the Yellow River delta, China. The results of fine root analysis showed that the fine roots of both black locust and velvet ash were mainly distributed in the soil layer at 0–20 cm depth and 50–150 cm from trees. The fine root distribution of both species suggests a strategy of avoiding salinity rather than salt –tolerance. The horizontal spread distance of fine roots of velvet ash was evidently longer than that of black locust. The fine root biomass, specific root length, specific root area, specific root volume and root activity were significantly higher for velvet ash in comparison with black locust. The results of soil analysis showed that rhizosphere soil pH of black locust and velvet ash were significantly lower compared with non-rhizosphere soil. The available N content in rhizosphere soil of black locust was higher than that of velvet ash. However, the contents of soluble salt, organic matter, available P and available K in rhizosphere soil of velvet ash were higher than those of black locust. The above results indicated that the differences between black locust and velvet ash in fine root distribution, characteristics and rhizosphere soil properties were the major reasons for that velvet ash showed stronger acclimation responses than black locust to the coastal saline soil.
  • Du, Shandong Academy of Forestry, 42 Wenhua East Road, Jinan 250014, P. R. China ORCID ID:E-mail: zydu@qq.com (email)
  • Wang, Shandong Academy of Forestry, Jinan, P. R. China ORCID ID:E-mail: wqh0228@163.com
  • Xing, Shandong Academy of Forestry, Jinan, P. R. China ORCID ID:E-mail: xingsj-126@126.com
  • Liu, Shandong Academy of Forestry, Jinan, P. R. China ORCID ID:E-mail: fchliu@126.com
  • Ma, Shandong Academy of Forestry, Jinan, P. R. China ORCID ID:E-mail: mby777@163.com
  • Ma, Shandong Academy of Forestry, Jinan, P. R. China ORCID ID:E-mail: mahlin@163.com
  • Liu, Shandong Academy of Forestry, Jinan, P. R. China ORCID ID:E-mail: llyldx@163.com
article id 894, category Research article
Heimo Karppinen, Mika Korhonen. (2013). Do forest owners share the public’s values? An application of Schwartz’s value theory. Silva Fennica vol. 47 no. 1 article id 894. https://doi.org/10.14214/sf.894
The purpose of this study is to investigate the differences in value priorities between Finnish forest owners and the general public. A conclusion is drawn whether and to what extent value changes in society are reflected in forest owners’ values and objectives, and, finally, in their actual forestry behavior. In addition, the study highlights the differences in value priorities among forest owners in various demographic groups. The data set used in this study was based on a nationwide mail survey on Finnish non-industrial private forest owners conducted in 2009 and consisting of 2116 observations of forest owners. Schwartz’s value theory was a good fit for testing the value priorities of forest owners. The three most important values were benevolence, security and conformity, both among the forest owners and the public. Tradition was ranked the fourth most important value by the forest owners, but very low by the public. The forest owners ranked universalism slightly lower than the public in general. This difference was clearly greater when the female forest owners were compared to women in the whole population. The probability of a forest owner belonging to the Softies (high emphasis on universalism and benevolence) increased with age and was higher for the female owners and the owners with recreational or multiple objectives compared to the indifferent owners. The multiobjective owners and recreationists had relatively similar value profiles. The previous literature suggests that multiobjective owners are the most active forest owner group and that recreationists and indifferent owners are the most passive groups in their timber supply behavior. The relationship between values and forestry behavior thus remains ambiguous.
  • Karppinen, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: heimo.karppinen@helsinki.fi (email)
  • Korhonen, Kämnerintie 7e 41, FI-00750 Helsinki, Finland ORCID ID:E-mail: mika.korhonen@gmx.com
article id 893, category Research article
Juha Heiskanen, Timo Saksa, Jaana Luoranen. (2013). Soil preparation method affects outplanting success of Norway spruce container seedlings on till soils susceptible to frost heave. Silva Fennica vol. 47 no. 1 article id 893. https://doi.org/10.14214/sf.893
Soil preparation is a common practice that precedes outplanting of Norway spruce (Picea abies (L.) Karst.) in Finland as it enhances the survival and early growth of seedlings. Mounding in particular has become more common with Norway spruce planting in recent years. However, on fine-grained soils, the postplanting performance of seedlings has been poorer than on coarser soils even with mounding. This study examined the effects of different soil preparation treatments (spot and ditch mounding with varying mound height, inverting, unprepared control with or without a herbicide) on the postplanting performance of Norway spruce container seedlings on till soil susceptible to frost heave in two outplanting forest sites in central Finland. The results indicate higher soil temperature and lower soil water content especially in the highest mounds. Mounds, however, subsided gradually during the study years. Seedling mortality was higher and the proportion of vigorous seedlings was lower in the unprepared treatments, mainly due to increased pine weevil (Hylobius abietis L.) damage. Frost heave was present mainly on ditch mounded and inverted spots. Glyphosate herbicide treatment showed no benefit compared to the untreated control in two years. Consequently, seedling damage and conditions in the planting spots were reflected in seedling growth which was enhanced in the mounded spots. However, varying mound height or thickness of mineral capping showed no clear difference in seedling growth. The results therefore suggest that ditch or spot mounding should be used on frost heave susceptible forest soils to promote plantation establishment. Inverting or having no soil preparation with or without herbicide is not recommended.
  • Heiskanen, Finnish Forest Research Institute, Suonenjoki Unit, Juntintie 154, FI-77600, Suonenjoki, Finland ORCID ID:E-mail: juha.heiskanen@metla.fi (email)
  • Saksa, Finnish Forest Research Institute, Suonenjoki Unit, Juntintie 154, FI-77600, Suonenjoki, Finland ORCID ID:E-mail: timo.saksa@metla.fi
  • Luoranen, Finnish Forest Research Institute, Suonenjoki Unit, Juntintie 154, FI-77600, Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@metla.fi
article id 917, category Research article
Anna Gunulf, Rebecka Mc Carthy, Jonas Rönnberg. (2012). Control efficacy of stump treatment and influence of stump height on natural spore infection by Heterobasidion spp. of precommercial thinning stumps of Norway spruce and birch. Silva Fennica vol. 46 no. 5 article id 917. https://doi.org/10.14214/sf.917
An alternative precommercial thinning technique results in trees being cut higher up the stem compared to the normal method using a brush saw. The aims of this study were to investigate if primary infection of Heterobasidion spp. on precommercial thinning stumps of Norway spruce and birch is influenced by stump height and to test the control efficacy of stump treatment with Phlebiopsis gigantea on precommercial thinning stumps of Norway spruce. Small Norway spruce and birch trees were felled on five sites in southern Sweden and their stumps subjected to natural spore infection. For each species, two treatments of stump height were created: 15 and 100 cm. Half of the Norway spruce stumps were treated with P. gigantea. After two months, 896 stumps were sampled and infection by Heterobasidion spp. was quantified. The height of stumps did not significantly influence infection frequency or size of infection on either tree species. Untreated Norway spruce stumps had an infection frequency of 55% while 31% of the treated stumps were infected. The control efficacy of stump treatment in terms of reduced relative infected area was 61–65%. The area occupied by Heterobasidion spp. on birch stumps was generally small, on average 0.4 cm2 per infected stump, although 15% of the stumps were infected. The risk of primary infection in Norway spruce dominated stands should be considered when precommercial thinning is conducted but the control efficacy and economy of stump treatment warrants further investigation before practical recommendations can be made.
  • Gunulf, Swedish University of Agricultural Sciences, Department of Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: anna.gunulf@slu.se (email)
  • Mc Carthy, Skogsforsk, Ekebo 2250, SE-268 90 Svalöv, Sweden ORCID ID:E-mail: Rebecka.McCarthy@skogforsk.se
  • Rönnberg, Swedish University of Agricultural Sciences, Department of Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: jonas.ronnberg@slu.se
article id 907, category Research article
Chunyu Zhang, Yazhou Zhao, Xiuhai Zhao, Klaus von Gadow. (2012). Species-habitat associations in a northern temperate forest in China. Silva Fennica vol. 46 no. 4 article id 907. https://doi.org/10.14214/sf.907
This contribution identifies species-habitat associations in a temperate forest in north-eastern China, based on the assumption that habitats are spatially autocorrelated and species are spatially aggregated due to limited seed dispersal. The empirical observations were obtained in a large permanent experimental area covering 660 x 320 m. The experimental area was subdivided into four habitat types using multivariate regression tree (MRT) analysis. According to an indicator species analysis, 38 of the 47 studied species were found to be significant indicators of the MRT habitat types. The relationships between species richness and topographic variables were found to be scale-dependent, while the great majority of the species shows distinct habitat-dependence. There are 188 potential species-habitat associations, and 114 of these were significantly positive or negative based on habitat randomization. We identified 139 significant associations using a species randomization. A habitat is not a closed system it may be both, either a sink or a source. Therefore, additional to the randomization, the Poisson Cluster Model (PCM) was applied. PCM considers the spatial autocorrelation of species and habitats, and thus appears to be more realistic than the traditional randomization processes. It identified only 37 associations that were significant. In conclusion, the deviation from the random process, i.e. the high degree of species spatial mingling may be explained by persistent immigration across habitats.
  • Zhang, Key Laboratory for Forest Resources & Ecosystem Processes of Beijing, Beijing Forestry University, Beijing 100083, China ORCID ID:E-mail: zcy_0520@163.com (email)
  • Zhao, Department of Landscape Architecture, School of Architecture, Tsinghua University, Beijing 100084, China ORCID ID:E-mail:
  • Zhao, Key Laboratory for Forest Resources & Ecosystem Processes of Beijing, Beijing Forestry University, Beijing 100083, China ORCID ID:E-mail:
  • von Gadow, Faculty of Forestry and Forest Ecology, Georg-August-University Göttingen, Büsgenweg 5, D-37077 Göttingen, Germany ORCID ID:E-mail: KGadow@gwdg.de
article id 42, category Research article
Pablo Martínez-Álvarez, Fernando Manuel Alves-Santos, Julio Javier Diez. (2012). In vitro and in vivo interactions between Trichoderma viride and Fusarium circinatum. Silva Fennica vol. 46 no. 3 article id 42. https://doi.org/10.14214/sf.42
Fusarium circinatum, a fungus that causes pitch canker disease, has been present in Europe since at least 2003, when it was detected in northern Spain and found to be producing severe damage in tree nurseries and pine plantations. In this study, we tested a method of biological control of the disease with Trichoderma viride, a fungal species successfully used against many other pathogens. In vitro and in vivo assays were carried out to test the efficacy of this antagonist in controlling F. circinatum. The T. viride isolate exerted a significant effect on the growth of F. circinatum in the in vitro assay, reducing the length of the pathogen colony by half. However, although we tested three different concentrations of the T. viride spore solution, no clear conclusions were obtained with regard to the effects on the Pinus radiata seedlings. To our knowledge, this is the first study carried out with the aim of using Trichoderma spp. to control pitch canker disease.
  • Martínez-Álvarez, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Avenida de Madrid 44, 34071 Palencia, Spain ORCID ID:E-mail: pmtnez@pvs.uva.es (email)
  • Alves-Santos, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Avenida de Madrid 44, 34071 Palencia, Spain ORCID ID:E-mail:
  • Diez, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Avenida de Madrid 44, 34071 Palencia, Spain ORCID ID:E-mail:
article id 82, category Research article
Nicole J. Fenton, Yves Bergeron. (2011). Dynamic old-growth forests? A case study of boreal black spruce forest bryophytes. Silva Fennica vol. 45 no. 5 article id 82. https://doi.org/10.14214/sf.82
Old-growth forests have sparked significant interest over the last twenty years and definitions have evolved from structure based to process based, acknowledging the diversity of forests that could be considered old growth. However studies frequently group all forests over a certain age into a single type, negating the dynamic processes that create old growth. In this study we examine a 2350-year chronosequence in boreal black spruce forests in northwestern Quebec to determine whether continued community change can be observed in the bryophyte layer. Bryophytes dominate the understory of boreal forests and influence ecosystem functioning, particularly in paludified forests where production exceeds decomposition in the organic layer. Community composition and richness changed throughout the chronosequence with no evidence of a steady state associated with an old-growth phase. In contrast the bryophyte community continued to evolve with multiple phases being evident. These results suggest that old-growth forests on the Clay Belt of northwestern Quebec and northeastern Ontario, Canada, should be regarded as part of the continuous gradient in forest development rather than a single state. This complicates conservation of these forests as multiple phases should be considered when planning forest reserves.
  • Fenton, Université du Québec en Abitibi-Témiscamingue, 445 Boulevard de l’Université, Rouyn-Noranda, Québec, Canada J9X 4E5 ORCID ID:E-mail: nicole.fenton@uqat.ca (email)
  • Bergeron, Université du Québec en Abitibi-Témiscamingue, 445 Boulevard de l’Université, Rouyn-Noranda, Québec, Canada J9X 4E5 ORCID ID:E-mail:
article id 95, category Research article
Venceslas Goudiaby, Suzanne Brais, Yvon Grenier, Frank Berninger. (2011). Thinning effects on jack pine and black spruce photosynthesis in eastern boreal forests of Canada. Silva Fennica vol. 45 no. 4 article id 95. https://doi.org/10.14214/sf.95
A decrease in the average diameter of commercially harvested tree species in the Eastern boreal forest of Canada has led to a decrease in availability of quality wood for the forest industry. Commercial thinning has been proposed as a means to increase stem diameter growth. However, little is known about physiological responses underlying species responses to thinning. We assessed the effect of canopy opening on the photosynthetic response of mature jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana (Mill.) BSP) trees. Two years after thinning and for each species, light response curves and the diurnal course of photosynthesis were characterized from measurements taken in a completely randomized block experiment on current-year and one-year-old needles of 12 trees from stands subjected to different levels of canopy opening. Soil water content, air and soil temperatures, and needle N concentration were not affected by thinning for either species. However, light availability increased with basal area removed and could explain the significantly positive relationship between thinning intensity and diurnal course of photosynthesis for one-year-old needles of jack pine. Black spruce photosynthesis did not respond to increases in light. Light-saturated rate of net photosynthesis (Amax), photosynthetic efficiency (α), light compensation point (LCP), and diurnal respiration (Rd) did not vary with thinning for either of the species. Jack pine and black spruce responses to thinning should be interpreted in light of species autecology.
  • Goudiaby, NSERC/UQAT/UQÀM Industrial Chair in Sustainable Forest Management, Université du Québec en Abitibi-Témiscamingue, Québec, Canada ORCID ID:E-mail: venceslas.goudiaby@uqat.ca (email)
  • Brais, NSERC/UQAT/UQÀM Industrial Chair in Sustainable Forest Management, Université du Québec en Abitibi-Témiscamingue, Québec, Canada ORCID ID:E-mail:
  • Grenier, NSERC/UQAT/UQÀM Industrial Chair in Sustainable Forest Management, Université du Québec en Abitibi-Témiscamingue, Québec, Canada ORCID ID:E-mail:
  • Berninger, University of Helsinki, Faculty of Agriculture and Forestry, Department of Forest Sciences, Finland ORCID ID:E-mail:
article id 94, category Research article
Youhong Peng, Ke Chen. (2011). Phylogeographic pattern of Populus cathayana in the southeast of Qinghai-Tibetan Plateau of China revealed by cpSSR markers. Silva Fennica vol. 45 no. 4 article id 94. https://doi.org/10.14214/sf.94
The vegetation in the Qinghai-Tibetan Plateau is thought to be highly sensitive and more vulnerable to global climate change than that of other areas. The uplift of the plateau as well as the climatic oscillations during glacial periods had a profound impact on plant species distribution and genetic diversity there. In the present study, seven pairs of cpSSR (chloroplast Simple Sequence Repeat) primers were utilized to detect genetic varieties of Populus cathayana Rehd populations from their natural range in the southeastern areas of Qinghai-Tibetan Plateau. A total of 28 alleles and 12 different haplotypes were detected. The proportion of haplotype variation among populations (GST = 0.794, NST = 0.900) indicated high level of genetic differentiation among populations and a significant phylogeographic structure (NST > GST, P < 0.05). This appears to support the hypothesis that these populations were derived from multiple refugia areas during the Quaternary climatic oscillations. Based on the haplotype network and mismatch distribution analyses, we found no evidence of postglacial range recolonization and expansion by P. cathayana in this region. This might be mainly due to the complex topography of the southeastern part of the Qinghai-Tibetan Plateau. The lofty mountain ranges and deep valleys in this region might have prevented long-distance migrations of this species during the climatic amelioration.
  • Peng, Chinese Academy of Sciences, Chengdu Institute of Biology, Chengdu, China ORCID ID:E-mail: pengyh@cib.ac.cn (email)
  • Chen, Chinese Academy of Sciences, Chengdu Institute of Biology, Chengdu, China ORCID ID:E-mail:
article id 450, category Research article
Miaoer Lu, Pekka Nygren, Jari Perttunen, Stephen G. Pallardy, David R. Larsen. (2011). Application of the functional-structural tree model LIGNUM to growth simulation of short-rotation eastern cottonwood. Silva Fennica vol. 45 no. 3 article id 450. https://doi.org/10.14214/sf.450
The functional-structural tree growth model LIGNUM was developed as a general research tool that can be applied to several tree species. The growth simulation of short-rotation eastern cottonwood (Populus deltoides Bartr. ex Marsh.) inherits the basic LIGNUM modeling concepts including modular tree structure, L-system-based description of structural development, and carbon budget. New developments of LIGNUM model in this study were the incorporation of a biochemically-derived photosynthesis submodel; nested time steps for simulating physiological processes, structural development, and annual biomass production; incorporation of field-measured weather data for modeling the response of physiological processes to environmental variation; and application of a Monte-Carlo voxel space submodel for simulating the stochasticity of tree growth and improving computational efficiency. A specific parameter system was applied for modeling P. deltoides growth in the central Missouri, USA, environment. This adaptation of LIGNUM was applied on modeling growth of P. deltoides in a short-rotation agroforestry practice. The simulated height and biomass growth were close to field observations. Visualization of simulation results closely resembled the trees growing in an open site. The simulated response of tree growth to variations in photon flux input was reasonable. The LIGNUM model may be used as a complement to field studies on P. deltoides in short-rotation forestry and agroforestry.
  • Lu, Deparment of Forestry, University of Missouri, Columbia, MO, USA ORCID ID:E-mail:
  • Nygren, The Finnish Society of Forest Science, P.O. 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: pekka.nygren@metla.fi (email)
  • Perttunen, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • Pallardy, Deparment of Forestry, University of Missouri, Columbia, MO, USA ORCID ID:E-mail:
  • Larsen, Deparment of Forestry, University of Missouri, Columbia, MO, USA ORCID ID:E-mail:
article id 450, category Research article
Miaoer Lu, Pekka Nygren, Jari Perttunen, Stephen G. Pallardy, David R. Larsen. (2011). Application of the functional-structural tree model LIGNUM to growth simulation of short-rotation eastern cottonwood. Silva Fennica vol. 45 no. 3 article id 450. https://doi.org/10.14214/sf.450
The functional-structural tree growth model LIGNUM was developed as a general research tool that can be applied to several tree species. The growth simulation of short-rotation eastern cottonwood (Populus deltoides Bartr. ex Marsh.) inherits the basic LIGNUM modeling concepts including modular tree structure, L-system-based description of structural development, and carbon budget. New developments of LIGNUM model in this study were the incorporation of a biochemically-derived photosynthesis submodel; nested time steps for simulating physiological processes, structural development, and annual biomass production; incorporation of field-measured weather data for modeling the response of physiological processes to environmental variation; and application of a Monte-Carlo voxel space submodel for simulating the stochasticity of tree growth and improving computational efficiency. A specific parameter system was applied for modeling P. deltoides growth in the central Missouri, USA, environment. This adaptation of LIGNUM was applied on modeling growth of P. deltoides in a short-rotation agroforestry practice. The simulated height and biomass growth were close to field observations. Visualization of simulation results closely resembled the trees growing in an open site. The simulated response of tree growth to variations in photon flux input was reasonable. The LIGNUM model may be used as a complement to field studies on P. deltoides in short-rotation forestry and agroforestry.
  • Lu, Deparment of Forestry, University of Missouri, Columbia, MO, USA ORCID ID:E-mail:
  • Nygren, The Finnish Society of Forest Science, P.O. 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: pekka.nygren@metla.fi (email)
  • Perttunen, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • Pallardy, Deparment of Forestry, University of Missouri, Columbia, MO, USA ORCID ID:E-mail:
  • Larsen, Deparment of Forestry, University of Missouri, Columbia, MO, USA ORCID ID:E-mail:
article id 113, category Research article
Jinsong Wang, Chunyu Zhang, Fucai Xia, Xiuhai Zhao, Lianhai Wu, Klaus von Gadow. (2011). Biomass structure and allometry of Abies nephrolepis (Maxim) in Northeast China. Silva Fennica vol. 45 no. 2 article id 113. https://doi.org/10.14214/sf.113
Above- and below-ground tree biomass structure and allometric relationships of Abies nephrolepis (Maxim) were assessed in an old secondary forest dominated by A. nephrolepis, Pinus koraiensis, Quercus mongolica, Tilia amurensis, Fraxinus mandshurica and Acer mono in northeast China. Based on the breast-height diameter (D), a total of 21 sample trees were divided into three tree size classes: the small trees (1 cm ≤ D < 10 cm), the medium trees (10 cm ≤ D < 20 cm) and the big trees (D ≥ 20 cm). The greatest amount of live branch biomass was located in the middle and bottom layers of the crown, while the largest foliage biomass was found in the middle layer in each tree size category. The relative contribution of canopy biomass components (live branches and foliage) decreased with increasing tree size, while that of coarse root biomass remained almost constant. The relationship between above- and belowground biomass was linear. D and tree height (H) decreased with increasing competition intensity. The small trees had lower average crown ratio and higher average height-to-diameter ratio than those of the medium and big trees. The big trees had higher average stem to foliage mass ratio than those of the small and medium trees. Crown ratio, height-to-diameter ratio and stem to foliage mass ratio were not correlated with competition intensity in the same tree size class. Root to shoot mass ratio was almost constant among tree sizes. Allometric equations based on D gave higher correlations compared to those with other stem diameters: at tree base, at 30-cm height and at crown base.
  • Wang, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing 100083, China ORCID ID:E-mail:
  • Zhang, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing 100083, China ORCID ID:E-mail:
  • Xia, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing 100083, China ORCID ID:E-mail:
  • Zhao, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing 100083, China ORCID ID:E-mail: zhaoxh@bjfu.edu.cn (email)
  • Wu, Rothamsted Research, Okehampton, Devon, UK ORCID ID:E-mail:
  • Gadow, Faculty of Forestry and Forest Ecology, Georg-August-University Göttingen, Göttingen, Germany ORCID ID:E-mail:
article id 41, category Research article
Ying Hou, Jintao Qu, Zukui Luo, Chao Zhang, Kaiyun Wang. (2011). Morphological mechanism of growth response in treeline species Minjiang fir to elevated CO2 and temperature. Silva Fennica vol. 45 no. 2 article id 41. https://doi.org/10.14214/sf.41
To test whether and how morphological traits are linked with growth responses of plants to temperature and CO2 is important for understanding the mechanism underlying how plant growth will respond to global warming. In this study, using closed-top chambers to mimic future elevated CO2 and temperature, the growth response, morphological traits of Minjiang fir (Abies faxoniana Rehd.et Wils.) and the relationship of the two were investigated after two years of exposure to the single and combined elevation of CO2 and temperature. The results showed that biomass of Minjiang fir was 21%, 31%, and 35% greater than the control in elevated CO2, elevated temperature and the combination of elevated CO2 and temperature treatments, respectively. Elevated CO2 and temperature significantly affected the morphology of Minjiang fir, and a few morphological traits were highly correlated with growth responses. Larger branch angles at the upper layer, crown volume, and relative crown length contributed to positive growth responses to elevated CO2, while decreased specific leaf area (SLA) constricted any further growth response. Leaf morphological traits were more closely correlated with the response ratio than crown did in the elevated temperature, while in the combination of elevated CO2 and temperature, crown was more correlated with the response ratio than the leaf morphological traits. Thus, our results indicate that morphological traits may contribute differently to growth responses under different experimental conditions.
  • Hou, Department of Life Sciences, Shangqiu Normal University, Shangqiu, China ORCID ID:E-mail:
  • Qu, Department of Life Sciences, Shangqiu Normal University, Shangqiu, China ORCID ID:E-mail:
  • Luo, School of Environment and Life Sciences, Kaili University, Kaili, China ORCID ID:E-mail:
  • Zhang, Shanghai Key Laboratory of Urbanization and Ecological Restoration, East China Normal University, Shanghai, China, and University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Wang, Shanghai Key Laboratory of Urbanization and Ecological Restoration, East China Normal University, Shanghai, China, and University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail: kywang@re.ecnu.edu.cn (email)
article id 40, category Research article
Jorge Martín-García, Elba Espiga, Valentín Pando, Julio Javier Diez. (2011). Factors influencing endophytic communities in poplar plantations. Silva Fennica vol. 45 no. 2 article id 40. https://doi.org/10.14214/sf.40
The fungal species associated with leaves and twigs from stands of Populus x euramericana in northern Spain were studied with the aim of evaluating the effects of several factors on endophytic communities in these plantations. Endophyte assemblages were analysed in 12 poplar plantations (clone I-214), chosen according to a factorial scheme with two factors: age and site quality. Crown condition, dendrometric variables and foliar nutrients were recorded in each sampled tree to evaluate their effects on endophytic communities. Fungal species richness and relative isolation frequency (RIF) were higher in young stands than in adult stands. Moreover, the age-related differences depended on site quality, with the lowest richness levels observed in adult stands located in poor sites. At stand level, endophyte assemblages varied among stands according to site quality and, to a lesser extent, stand age. On the other hand, crown discoloration, total height and foliar concentrations of iron and zinc may be key indicators of endophytic communities in poplar plantations, at tree level.
  • Martín-García, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Avenida de Madrid 57, 34004 Palencia, Spain, and Forestry Engineering, University of Extremadura, Plasencia, Spain ORCID ID:E-mail: jorgemg@pvs.uva.es (email)
  • Espiga, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Palencia, Spain ORCID ID:E-mail:
  • Pando, Statistics and Operations Research Department, University of Valladolid, Spain ORCID ID:E-mail:
  • Diez, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Palencia, Spain ORCID ID:E-mail:
article id 130, category Research article
Yongqing Yang, Yinan Yao, Xuejiang Zhang. (2010). Comparison of growth and physiological responses to severe drought between two altitudinal Hippophae rhamnoides populations. Silva Fennica vol. 44 no. 4 article id 130. https://doi.org/10.14214/sf.130
Growth and physiological differences in response to drought were compared between two sea buckthorn (Hippophae rhamnoides L.) populations inhabited in the southeast of the Qinghai-Tibetan Plateau of China. The experimental design included two water regimes (100% and 25% of field capacity) and two populations from the low and high altitude zone. Our experiments were conducted in a naturally lit greenhouse under semi-controlled environmental conditions for a whole growing season in a dry valley (1800 m above the sea level). We found that drought tolerance is highly related to the plant antioxidant capacity and water use efficiency as well as leaf nutrient status in H. rhamnoides. The highland population (HP) experienced a greater inhibition in plant growth and leaf enlargement, lower leaf nitrogen and phosphorus content, lower root nodule biomass and root mass/foliage area ratio, and higher leaf water content loss paralleling with higher enhancement of abscisic acid level in response to drought, as compared with lowland population (LP). Additionally, reduction of leaf lignin content in HP further reduced its drought tolerance. On the contrary, LP showed effective adaptation strategies such as improvement of water economy and maintaining high ascorbic acid content. Therefore, we conclude that LP was more tolerant to drought than HP, and could be selected for reforestation in the dry valleys of upper Minjiang River regions in China.
  • Yang, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China & College of Life Sciences, Chongqing Normal University, Chongqing, 400047, China ORCID ID:E-mail:
  • Yao, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China ORCID ID:E-mail: yaoya@ms.xjb.ac.cn (email)
  • Zhang, Institute for Plant Protection and Soil sciences, Hubei Academy of Agricultural Sciences, Wuhan, 430064, China ORCID ID:E-mail:
article id 130, category Research article
Yongqing Yang, Yinan Yao, Xuejiang Zhang. (2010). Comparison of growth and physiological responses to severe drought between two altitudinal Hippophae rhamnoides populations. Silva Fennica vol. 44 no. 4 article id 130. https://doi.org/10.14214/sf.130
Growth and physiological differences in response to drought were compared between two sea buckthorn (Hippophae rhamnoides L.) populations inhabited in the southeast of the Qinghai-Tibetan Plateau of China. The experimental design included two water regimes (100% and 25% of field capacity) and two populations from the low and high altitude zone. Our experiments were conducted in a naturally lit greenhouse under semi-controlled environmental conditions for a whole growing season in a dry valley (1800 m above the sea level). We found that drought tolerance is highly related to the plant antioxidant capacity and water use efficiency as well as leaf nutrient status in H. rhamnoides. The highland population (HP) experienced a greater inhibition in plant growth and leaf enlargement, lower leaf nitrogen and phosphorus content, lower root nodule biomass and root mass/foliage area ratio, and higher leaf water content loss paralleling with higher enhancement of abscisic acid level in response to drought, as compared with lowland population (LP). Additionally, reduction of leaf lignin content in HP further reduced its drought tolerance. On the contrary, LP showed effective adaptation strategies such as improvement of water economy and maintaining high ascorbic acid content. Therefore, we conclude that LP was more tolerant to drought than HP, and could be selected for reforestation in the dry valleys of upper Minjiang River regions in China.
  • Yang, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China & College of Life Sciences, Chongqing Normal University, Chongqing, 400047, China ORCID ID:E-mail:
  • Yao, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China ORCID ID:E-mail: yaoya@ms.xjb.ac.cn (email)
  • Zhang, Institute for Plant Protection and Soil sciences, Hubei Academy of Agricultural Sciences, Wuhan, 430064, China ORCID ID:E-mail:
article id 139, category Research article
Ulf Sikström, Curt Almqvist, Gunnar Jansson. (2010). Growth of Pinus sylvestris after the application of wood ash or P and K fertilizer to a peatland in southern Sweden. Silva Fennica vol. 44 no. 3 article id 139. https://doi.org/10.14214/sf.139
The effects of the application of wood ash and of fertilizer regimes including phosphorus (P) and potassium (K), with and without simultaneous addition of nitrogen (N), were investigated on a stand of Scots pine (Pinus sylvestris L.) saplings growing on a drained oligotrophic peatland site in southern Sweden. A randomized block design was used. Tree growth and concentrations of various elements in the needles were measured. The addition of similar doses of P (approx. 40 kg P ha–1) from different sources resulted in similar growth responses, amounting to 1.6–1.9 m3 ha–1 yr–1 of stem wood over the 26-year study. The P source was either wood ash (2500 kg d.w. ha–1) or PK-fertilizer (raw phosphate and potassium chloride). In response to several treatments there were both increased numbers of trees and increased growth of individual trees. The high PK-dose (40 kg P ha–1 and 80 kg K ha–1) appeared to result in a larger growth increase than the low dose (20 kg P ha–1 and 40 kg K ha–1). The N treatment had no additional effect on growth. In the control plots, tree growth was more or less negligible (0.04 m3 ha–1 yr–1). After almost 26 years, concentrations of P and K in the needles of treated plants were still higher than in the untreated control plants. Nevertheless, in spite of the elevated P concentration, P appears to limit the growth of Scots pine. In conclusion, after sufficient drainage of this type of peatland site, it is possible for a forest stand to develop to the pole stage if wood ash or PK-fertilizer is applied.
  • Sikström, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: ulf.sikstrom@skogforsk.se (email)
  • Almqvist, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail:
  • Jansson, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail:
article id 137, category Research article
Alberto Bueno, Julio J. Diez, Mercedes M. Fernández. (2010). Ophiostomatoid fungi transported by Ips sexdentatus (Coleoptera; Scolytidae) in Pinus pinaster in NW Spain. Silva Fennica vol. 44 no. 3 article id 137. https://doi.org/10.14214/sf.137
Ips sexdentatus (Coleoptera; Scolytidae) is one of the main vectors of ophiostomatoid blue stain fungi that can cause mortality of healthy conifers. For this reason, our objective was to identify the fungal species carried by this bark beetle in Maritime pine (Pinus pinaster) in north-western Spain. We collected insects from naturally infected pines placed them on malt extract agar (MEA) and left to walk freely on culture plates. Plant tissues (phloem and xylem) from adult pines were cultivated in moist chambers and also on MEA. At the same time, we inoculated pine logs with living insects in the laboratory. Four ophiostomatoid fungi appeared: Ophiostoma ips, Ophiostoma brunneo-ciliatum, Ceratocystiopsis minuta and Ophiostoma sp., as well as Graphium and Sporothrix imperfect stages. Moreover there were seven saprophytic species: Penicillium sp., Trichoderma sp., Verticillium sp., Mucor sp., Aspergillus niger, Gliocladium viride and Scopulariopsis brevicaulis, and the pathogenic Ophiostoma ips. The fructification percentage of the ophiostomatoid species was low, however; its imperfect stage Sporothrix/Hyalorhinocladiella produced high quantity of conidiophores.
  • Bueno, University of Valladolid, Dept of Agroforestry Sciences, Palencia, Spain ORCID ID:E-mail:
  • Diez, University of Valladolid, Dept of Agroforestry Sciences, Palencia, Spain ORCID ID:E-mail:
  • Fernández, University of Valladolid, Dept of Agroforestry Sciences, Palencia, Spain ORCID ID:E-mail: mffernan@agro.uva.es (email)
article id 153, category Research article
Dirk Bieker, Steffen Rust. (2010). Non-destructive estimation of sapwood and heartwood width in Scots pine (Pinus sylvestris L.). Silva Fennica vol. 44 no. 2 article id 153. https://doi.org/10.14214/sf.153
Accurate estimates of the water conducting sapwood area are necessary to scale sapflow measurements to tree and stand level transpiration. We tested a non-destructive method, electric resistivity tomography (ERT), to estimate the area of conductive sapwood in 9 Pinus sylvestris L. trees in lower Saxony, Germany. Tomograms were compared to cross-sections stained with benzidine after harvesting. All tomograms displayed a distinct pattern of low resistivity at the stem perimeter and high resistivity in the stem centre with a steep increase in resistivity in between, assumed to indicate the transition from sapwood to heartwood. The tomograms showed a sapwood width 2 cm smaller than the staining method. This indicates that staining methods overestimate the amount of active sapwood because when heartwood is formed, moisture content decreases before extractive contents reach levels visible by staining. The ERT method is a new powerful method for the non-destructive estimation of sapwood and heartwood width.
  • Bieker, University of Applied Sciences and Arts, Faculty of Resource Management, Büsgenweg 1a, D-37077 Göttingen, Germany ORCID ID:E-mail:
  • Rust, University of Applied Sciences and Arts, Faculty of Resource Management, Büsgenweg 1a, D-37077 Göttingen, Germany ORCID ID:E-mail: rust@hawk-hhg.de (email)
article id 149, category Research article
Juha Kaitera, Heikki Nuorteva. (2010). Effects of Melampyrum extracts on the growth of axenic cultures of Cronartium flaccidum and Peridermium pini. Silva Fennica vol. 44 no. 2 article id 149. https://doi.org/10.14214/sf.149
For 3–6 months, mycelial colonies cultured from 5 isolates of each of two pine stem rusts (Cronartium flaccidum and Peridermium pini) were grown on nutrient-rich agar supplemented with Melampyrum extracts. Non-autoclaved extracts of M. pratense significantly reduced the growth of P. pini. The growth of C. flaccidum isolates was slightly stimulated after the second month of incubation but after that was inhibited during incubation months 4–6. We observed considerable variation in colony growth, a significant component of which was explained by incubation time, isolate, growth medium and their interaction. Rust species (C. flaccidum or P. pini) was not an important factor in growth variation. While sterilized extracts of M. pratense, M. sylvaticum and M. nemorosum did not significantly affect growth, colonies of C. flaccidum were slightly stimulated, whereas colonies of P. pini were slightly inhibited. Generally, isolates of P. pini grew better and showed a slower rate of degeneration than C. flaccidum on all media.
  • Kaitera, Finnish Forest Research Institute, Northern Finland Regional Unit, FI-91500 Muhos, Finland ORCID ID:E-mail: juha.kaitera@metla.fi (email)
  • Nuorteva, Finnish Forest Research Institute, Southern Finland Regional Unit, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 170, category Research article
Ryoichi Doi, Senaratne L. Ranamukhaarachchi. (2009). Community-level physiological profiling in monitoring rehabilitative effects of Acacia auriculiformis plantation on degraded land in Sakaerat, Thailand. Silva Fennica vol. 43 no. 5 article id 170. https://doi.org/10.14214/sf.170
This study was conducted to investigate the rehabilitative effects of planting Acacia auriculiformis trees on degraded land by observing variations in soil bacterial community profiles provided by community-level physiological profiling. Soil bacterial and physicochemical comparisons between an original evergreen forest and the Acacia plantation plot, established on an area severely degraded as a result of deforestation, showed that most soil characteristics were rehabilitated 18 to 19 years after the plantation of Acacia according to single variables, Shannon and Simpson diversity indices based on the community-level physiological profiles, principal component analysis and redundancy analysis. However, a more strict statistical comparison, discriminant analysis, completely discriminated between the Acacia plantation and the evergreen forest soils when the community-level physiological profiles were compared. Thus, the Acacia plantation soil was shown to still be in the process to full recovery. Here, we discuss the relevance of planting A. auriculiformis in land rehabilitation schemes in savanna regions.
  • Doi, AFE Building, School of Environment, Resources and Development, Asian Institute of Technology, Pathumthani 12120, Thailand ORCID ID:E-mail: roird@aeiou.pt (email)
  • Ranamukhaarachchi, AFE Building, School of Environment, Resources and Development, Asian Institute of Technology, Pathumthani 12120, Thailand ORCID ID:E-mail:
article id 169, category Research article
Susanne von Bargen, Elise Grubits, Risto Jalkanen, Carmen Büttner. (2009). Cherry leaf roll virus – an emerging virus in Finland? Silva Fennica vol. 43 no. 5 article id 169. https://doi.org/10.14214/sf.169
Cherry leaf roll virus, CLRV, is a plant pathogen that infects a variety of deciduous trees and shrubs in temperate regions. Little is known about its occurrence at high latitudes and especially in Finnish birch species. Still, symptoms that seemed to be associated with CLRV such as vein banding, leaf roll and decline have been observed in birch trees throughout the country since the summer of 2002. Six different birch species, subspecies or varieties, i.e. Betula pubescens subsp. pubescens (downy birch), B. pendula (silver birch), B. nana (dwarf birch), B. pubescens var. appressa (Kiilopää birch), B. pubescens subsp. czerepanovii (mountain birch) and B. pendula var. carelica (curly birch) originating from all over Finland were assessed by immunocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR) for CLRV infection. It was shown that CLRV is widely distributed in B. pendula and B. pubescens throughout the country. Furthermore, dwarf birch, mountain birch, Kiilopää birch and curly birch were confirmed to be previously unkown hosts of CLRV. Genetic analysis of virus sequence variants originating from Finnish birch trees revealed atypical phylogenetic relationships. In contrast to CLRV isolates from birches growing in the United Kingdom and Germany which clustered exclusively within group A, Finnish CLRV isolates belonged either to group B, D or E. Thus, virus population structure in Finnish birches seems to be more variable and host plant dependency seems not to apply for Finnish CLRV isolates.
  • Bargen, Humboldt-Universität zu Berlin, Department für Nutzpflanzen- und Tierwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail: susanne.von.bargen@agrar.hu-berlin.de (email)
  • Grubits, Humboldt-Universität zu Berlin, Department für Nutzpflanzen- und Tierwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail:
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: risto.jalkanen@metla.fi
  • Büttner, Humboldt-Universität zu Berlin, Department für Nutzpflanzen- und Tierwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail:
article id 168, category Research article
Saila Varis, Anne Pakkanen, Aina Galofré, Pertti Pulkkinen. (2009). The extent of south-north pollen transfer in Finnish Scots pine. Silva Fennica vol. 43 no. 5 article id 168. https://doi.org/10.14214/sf.168
In order to evaluate the possibility of long distance gene flow in Scots pine (Pinus sylvestris L.), we measured the amount and germinability of airborne pollen and flowering phenology in central, northern, and northernmost Finland during 1997–2000. Totally 2.3% of the detected germinable pollen grains were in the air prior to local pollen shedding. The mean number of germinable pollen grains m–3 air per day was lower prior to local pollen shedding, but in the year 2000 there were more germinable pollen grains in the air of central study site prior to local pollen shedding. Prior to the onset of pollen shedding, 7.5% of female strobili which we observed were receptive. On average female strobili became receptive three days earlier than local pollen shedding started. During the period of pollen shedding in the central study site, we detected germinable airborne pollen in the northern site in years 1997, 1999 and 2000. At the northermost site, we detected germinable airborne pollen during the pollen-shedding period of the northern site in 2000. Our detection of germinable airborne pollen and synchrony of strobili maturation from south to north suggest that populations of Scots pine in central and northern Finland may provide genetic material to populations in northern and northernmost Finland, respectively.
  • Varis, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: saila.varis@metla.fi (email)
  • Pakkanen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Galofré, Passeig de l’estació 21, 5-1, 43800 Valls, Tarragona, Spain ORCID ID:E-mail:
  • Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, Karkkilantie 247, FI-12600 Läyliäinen, Finland ORCID ID:E-mail:
article id 203, category Research article
Matti Maltamo, Jussi Peuhkurinen, Jukka Malinen, Jari Vauhkonen, Petteri Packalén, Timo Tokola. (2009). Predicting tree attributes and quality characteristics of Scots pine using airborne laser scanning data. Silva Fennica vol. 43 no. 3 article id 203. https://doi.org/10.14214/sf.203
The development of airborne laser scanning (ALS) during last ten years has provided new possibilities for accurate description of the living tree stock. The forest inventory applications of ALS data include both tree and area-based plot level approaches. The main goal of such applications has usually been to estimate accurate information on timber quantities. Prediction of timber quality has not been focused to the same extent. Thus, in this study we consider here the prediction of both basic tree attributes (tree diameter, height and volume) and characteristics describing tree quality more closely (crown height, height of the lowest dead branch and sawlog proportion of tree volume) by means of high resolution ALS data. The tree species considered is Scots pine (Pinus sylvestris), and the field data originate from 14 sample plots located in the Koli National Park in North Karelia, eastern Finland. The material comprises 133 trees, and size and quality variables of these trees were modeled using a large number of potential independent variables calculated from the ALS data. These variables included both individual tree recognition and area-based characteristics. Models for the dependent tree characteristics to be considered were then constructed using either the non-parametric k-MSN method or a parametric set of models constructed simultaneously by the Seemingly Unrelated Regression (SUR) approach. The results indicate that the k-MSN method can provide more accurate tree-level estimates than SUR models. The k-MSN estimates were in fact highly accurate in general, the RMSE being less than 10% except in the case of tree volume and height of the lowest dead branch.
  • Maltamo, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail: matti.maltamo@joensuu.fi (email)
  • Peuhkurinen, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Malinen, Finnish Forest Research Institute, Joensuu Research Unit, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Vauhkonen, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Packalén, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Tokola, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 192, category Research article
Heli Peltola, Jaume Gort, Pertti Pulkkinen, Ane Zubizarreta Gerendiain, Jouni Karppinen, Veli-Pekka Ikonen. (2009). Differences in growth and wood density traits in Scots pine (Pinus sylvestris L.) genetic entries grown at different spacing and sites. Silva Fennica vol. 43 no. 3 article id 192. https://doi.org/10.14214/sf.192
In forest breeding, stem volume has typically taken as the most important selection trait, whereas less attention has been given to wood density traits. In this work, we investigated the effects of spacing and genetic entry on the growth, yield and wood density traits in 20 year old Scots pines (Pinus sylvestris L.) based on 10 genetic entries harvested from a spacing trial (stand density range 2000–4000 trees/ha) in central Finland. In order to study also the site effects, we harvested additional material from a trial located in southern Finland (stand density of 2000 trees/ha). Compared to growth and yield properties, wood density traits showed a lower phenotypic variation. Phenotypic correlations among different traits were negative, and mostly moderate to high, suggesting that selection for one trait would simultaneously affect the others. In addition, moderate to strong phenotypic correlations were found among different wood density traits. Stem volume (V) and breast height diameter (DBH) were the largest in widest spacing, whereas in the densest one tree height (H) and latewood percentage were the highest. Genetic entry affected H and wood density traits regardless of spacing. When comparing two sites (with same stand density), genetic entry affected H, whereas site affected DBH and wood density traits. Ranking between genetic entries changed depending on the trait, spacing or site considered. Therefore, no overall ranking was possible. However, we could identify genetic entries having a high V and a relatively high wood density, showing potential for future forest regeneration material.
  • Peltola, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail: heli.peltola@joensuu.fi (email)
  • Gort, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, Karkkilantie 247, FI-12600 Läyliäinen, Finland ORCID ID:E-mail:
  • Zubizarreta Gerendiain, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Karppinen, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Ikonen, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 465, category Research article
Ken Olaf Storaunet, Jørund Rolstad, Målfrid Toeneiet, Erlend Rolstad. (2008). Effect of logging on the threatened epiphytic lichen Usnea longissima: a comparative and retrospective approach. Silva Fennica vol. 42 no. 5 article id 465. https://doi.org/10.14214/sf.465
Usnea longissima is a conspicuous circumboreal “beard lichen” draping tree canopies in moist coastal and mountainous forests. It is extirpated in many European and North-American localities, presumably due to industrial forestry and air pollution, but still has a stronghold in parts of Scandinavia and U.S. and Canadian Pacific Northwest. Using a retrospective approach, we reconstructed the stand histories in 24 plots (0.1 ha) of mature Norway spruce (Picea abies) forest stands in Lillehammer, Norway, of which 21 was selected due to the presence of U. longissima. Number of trees with U. longissima present within plots varied from 4 to 37 and number of visible thalli from 12 to 469. The detailed stand reconstructions were done by means of tree-ring analysis of 517 living trees and the size and decay stage of 1423 stumps from logging and 467 dead trees. Total harvested volume during the last 100 years ranged 100–370 m3ha–1 (representing 40–350% of the present-day standing volume), and present amount of dead wood ranged 2–87 m3ha–1 (1.0–37% of the standing volume). All stands had been selectively logged 2–4 times during the last 100 years, of which 5 stands almost to a clearcut appearance. We used a variety of present-day and historic forest structural variables, both at the scale of study plots and individual trees, to predict the occurrence and abundance of U. longissima. Although most forest stand variables failed in this respect, there were indications of a certain negative influence of the historic logging activity. Number of thalli present on trees showed a unimodal relationship to present-day tree density, indicating that medium dense forest stands are most favorable for U. longissima. We tentatively suggest that selective logging, securing lichen-rich trees, may be a viable management option to keep tree density at a moderate level in the long run, thereby enhancing growth and establishment of U. longissima.
  • Storaunet, Norwegian Forest and Landscape Institute, P.O. Box 115, NO-1431 Ås, Norway ORCID ID:E-mail: ken.storaunet@skogoglandskap.no (email)
  • Rolstad, Norwegian Forest and Landscape Institute, P.O. Box 115, NO-1431 Ås, Norway ORCID ID:E-mail:
  • Toeneiet, Norwegian Forest and Landscape Institute, P.O. Box 115, NO-1431 Ås, Norway ORCID ID:E-mail:
  • Rolstad, Norwegian Forest and Landscape Institute, P.O. Box 115, NO-1431 Ås, Norway ORCID ID:E-mail:
article id 468, category Research article
Antti Lännenpää, Tuomas Aakala, Heikki Kauhanen, Timo Kuuluvainen. (2008). Tree mortality agents in pristine Norway spruce forests in northern Fennoscandia. Silva Fennica vol. 42 no. 2 article id 468. https://doi.org/10.14214/sf.468
We examined tree mortality agents in pristine old Norway spruce (Picea abies (L.) Karst.) forests in northern Finland and northwestern Russia. The data was collected on nine 40 m   400 m transects. The primary mortality agents of recently dead trees were recorded and their frequencies were calculated. The pattern of tree growth prior to death was studied based on increment core samples and compared with the growth of healthy dominant trees. Of all recently dead trees, 72% could be associated with a primary mortality agent. In both study areas the most common primary mortality agent was a Coniophora (Mérat) DC. -genus fungi, which was found on average in 33% of trees sampled. The fungi Phellinus chrysoloma (Fr.) Don and Onnia leporina (Fr.) H. Jahn as mortality agents were more common in the Finnish area compared to the Russian area. Analysis on the growth patterns indicated weak differences between different pathogens’ influence on prior-to-death growth of trees, so that fungi rotting the whole tree decreased tree growth more rapidly than fungi rotting only the heart wood. The results demonstrated that in old Norway spruce forests of northern Fennoscandia the most common primary tree mortality agents were wood rotting fungi, which weaken the mechanical stability of tree stems until they fall due to snow or wind, which should be considered only as secondary mortality agents. It is evident that tree death in pristine forest typically results from a long-lasting process involving both biotic and abiotic factors.
  • Lännenpää, Department of Forest Ecology, University of Helsinki, Finland ORCID ID:E-mail:
  • Aakala, Department of Forest Ecology, University of Helsinki, Finland ORCID ID:E-mail: tuomas.aakala@helsinki.fi (email)
  • Kauhanen, Kolari Research Unit, Finnish Forest Research Institute, Finland ORCID ID:E-mail:
  • Kuuluvainen, Department of Forest Ecology, University of Helsinki, Finland ORCID ID:E-mail:
article id 253, category Research article
Riitta Väänänen, Mika Nieminen, Martti Vuollekoski, Hannu Nousiainen, Tapani Sallantaus, Eeva-Stiina Tuittila, Hannu Ilvesniemi. (2008). Retention of phosphorus in peatland buffer zones at six forested catchments in southern Finland. Silva Fennica vol. 42 no. 2 article id 253. https://doi.org/10.14214/sf.253
Our current knowledge of the P retention efficiency of peatland buffer zone areas used to reduce sediment and nutrient leaching from forestry areas is insufficient. Especially the role of P sorption by soil in buffer zones needs closer examination as there is considerable variation in the efficiency of P retention. Six sites in southern Finland were chosen for the study. The buffer zone areas varied between 0.1–4.9% of the catchment area. A total of 10 kg of solute PO4–P was added to the inflow of the buffer zone areas and the concentrations of PO4–P in inflow and outflow were measured for 2–4 years. P retention characteristics of the surface peat were determined with sorption-desorption isotherms before and after PO4–P addition and the effective buffer zone area over which the added P was spread was determined from soil water samples. P retention in the two largest buffer zone areas was complete (100% retention), and the third largest buffer retained 94%. Retention in the three smallest buffer zones was 24%, 95% and 95% of the added P. As a result of P addition reduction in peat P retention capacity was detected in three out of four cases. The effective buffer zone area varied from 67% to 100% of the total buffer zone area. Factors contributing to efficient P retention were large buffer size and low hydrological load whereas high hydrological load combined with the formation of preferential flow paths, especially during early spring or late autumn was disadvantageous. High P retention capacity in peat contributed to the sustainability of P retention. The study showed that even relatively small buffer zone areas are able to efficiently reduce P load.
  • Väänänen, Department of Forest Ecology, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: riitta.vaananen@helsinki.fi (email)
  • Nieminen, Finnish Forest Research Institute, Vantaa Research Unit, Finland ORCID ID:E-mail:
  • Vuollekoski, Finnish Forest Research Institute, Vantaa Research Unit, Finland ORCID ID:E-mail:
  • Nousiainen, Finnish Forest Research Institute, Vantaa Research Unit, Finland ORCID ID:E-mail:
  • Sallantaus, Finnish Environment Institute, Nature Division, Helsinki, Finland ORCID ID:E-mail:
  • Tuittila, Department of Forest Ecology, University of Helsinki, Finland ORCID ID:E-mail:
  • Ilvesniemi, Finnish Forest Research Institute, Vantaa Research Unit, Finland ORCID ID:E-mail:
article id 251, category Research article
Lina R. Steinke, Andrea C. Premoli, Cintia P. Souto, Mikael Hedrén. (2008). Adaptive and neutral variation of the resprouter Nothofagus antarctica growing in distinct habitats in north-western Patagonia. Silva Fennica vol. 42 no. 2 article id 251. https://doi.org/10.14214/sf.251
N. antarctica occurs in the widest range of habitat types among all South American Notho–fagus. The aim of this study is to investigate adaptive responses by variation in morphological (tree form and leaf characters), and environmental traits (soils) of the polymorphic N. ant–arctica. Also we analyze the effect of genetic drift and limited gene flow in such predominantly apomict by means of neutral variation (isozymes). We studied four potentially different morphological variants each associated with a separate habitat 1) an arboreal variant growing in optimal environments; 2) a sparsely branched variant of temporarily flooded basins or flats; 3) a dwarf variant growing at high elevation, and 4) a shrub-like variant inhabiting matorral environments. The study was restricted latitudinally to Nahuel Huapi National Park, Argentina. For each habitat type we investigated two sites. Nothofagus antarctica shows locally occurring phenotypes. The forest and the high elevation variants were morphologically distinct from the matorral and the basin types. The latter were undistinguishable except for more profuse branching in the matorral type as a result of sprouting due to recent fires. Isozyme evidence indicates a great deal of within-population genetic diversity which is maintained by outcrossing and significant among-site divergence (FST = 18%) that reflects limited gene flow.The apparent high phenotypic and genetic variability in N. antarctica is due to both plasticity and genotypic effects as a result of stable population structure and long periods of isolation which may be reinforced by selection at diverse biotopes.
  • Steinke, Plant Ecology and Systematics, Lund University, Ecology Department, 223 62 Lund, Sweden ORCID ID:E-mail:
  • Premoli, Universidad Nacional del Comahue, Laboratorio Ecotono – CRUB, Quintral 1250, 8400 Bariloche, Argentina ORCID ID:E-mail: apremoli@crub.uncoma.edu.ar (email)
  • Souto, Universidad Nacional del Comahue, Laboratorio Ecotono – CRUB, Quintral 1250, 8400 Bariloche, Argentina ORCID ID:E-mail:
  • Hedrén, Plant Ecology and Systematics, Lund University, Ecology Department, 223 62 Lund, Sweden ORCID ID:E-mail:
article id 469, category Research article
Henri Vanhanen, Timo O. Veteli, Sonja Päivinen, Seppo Kellomäki, Pekka Niemelä. (2007). Climate change and range shifts in two insect defoliators: gypsy moth and nun moth – a model study. Silva Fennica vol. 41 no. 4 article id 469. https://doi.org/10.14214/sf.469
Environmental factors influenced by global climate change determine the distribution ranges of organisms. Especially ectothermic animals are expected to shift their distribution ranges northwards in the next hundred years or so. In this study simulations made with CLIMEX-modelling software were used to predict the future distribution ranges of two Central European serious forest pest species: the nun moth (Lymantria monacha L. (Lepidoptera: Lymantriidae)) and the gypsy moth (L. dispar L). The software calculates an ecoclimatic index based on the life cycle requirements of a species and thus represents the probability of a viable population to exist at a certain location. Three different climate warming scenarios were considered: temperature increase of 1.4, 3.6 and 5.8°C. Simulations generated with the current climate conditions corresponded well to the current distributions of the species. The climate warming scenarios shifted the northern boundary of the distribution for both of these species north by c. a. 500–700 km. Also the southern edge of the ranges retracted northwards by 100–900 km. The results of this study are in agreement with the results of empirical studies on other species. Being serious pest species, these species pose a potential threat to silviculture and therefore, have to be considered in the planning of forest management practices.
  • Vanhanen, Faculty of Forestry, University of Joensuu, P.O.B. 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Veteli, Faculty of Biosciences, University of Joensuu, P.O.B. 111, FI-80101, Joensuu, Finland ORCID ID:E-mail: timo.veteli@joensuu.fi (email)
  • Päivinen, Faculty of Forestry, University of Joensuu, P.O.B. 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Kellomäki, Faculty of Forestry, University of Joensuu, P.O.B. 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Niemelä, Faculty of Forestry, University of Joensuu, P.O.B. 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 284, category Research article
Tuomo Nurminen, Jaakko Heinonen. (2007). Characteristics and time consumption of timber trucking in Finland. Silva Fennica vol. 41 no. 3 article id 284. https://doi.org/10.14214/sf.284
Cost efficiency and flexibility have become increasingly important in the logistics of cut-to-length harvesting operations. At the same time, the operating conditions for long-distance transportation have become more demanding and variable. Since the number of log products has increased and the size of harvesting sites has decreased, loads of timber must increasingly be collected from several log decks, increasing the time consumption and costs of the trucking operation. The objectives of this study were to formulate time-consumption models for typical timber transportation activities in Finland and introduce a statistical procedure for examining the variation in time consumption during the trucking phases. The study used a combination of time studies and follow-up studies based on empirical data for 368 loads (a total volume of nearly 18 000 m3) collected from one wood procurement district in central Finland. The model included the following explanatory factors: driving distance, number of log decks, log product and load volume. Since transportation includes several phases and since many factors affect the work performance, significant variation in the total transportation time was observed. This makes planning and cost accounting more difficult. The models developed in this study are a promising initial tool to support route planning and optimization, and cost and profitability calculations for trucking entrepreneurs and the forest industry.
  • Nurminen, University of Joensuu, Faculty of Forest Sciences; Forest Agency Tuomo Nurminen, Joensuuntie 5 B 8, FI-41800 Korpilahti, Finland ORCID ID:E-mail:
  • Heinonen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 280, category Research article
Mika Nieminen, Mikko Moilanen, Sirpa Piirainen. (2007). Phosphorus allocation in surface soil of two drained peatland forests following wood and peat ash application – why effective adsorption on low sorptive soils? Silva Fennica vol. 41 no. 3 article id 280. https://doi.org/10.14214/sf.280
Fertilization of drained peatland forests with wood ash and different commercial phosphorus fertilizers (calcium phosphates) generally give similar stand growth responses. However, it has been shown that use of calcium phosphate fertilizers generally lead to highly increased P release to recipient water courses. On the other hand, no corresponding release has been reported after ash fertilization. Soil samples from the surface peats from a nutrient poor and a fertile drained peatland site were collected before and 1–4 years after application of five different types of ash products. The changes over time in the different chemical forms of P in the substrate were studied. The results indicated that the reason for the low liability to leaching of ash fertilizers was that significant amounts of P are adsorbed by Al and Fe during weathering of the ash fertilizers. However, further studies are needed to clarify whether the adsorption of P occurs with the Al and Fe of the ash or the native Al and Fe compounds present in soil before ash fertilization.
  • Nieminen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: mika.nieminen@metla.fi (email)
  • Moilanen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Piirainen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 280, category Research article
Mika Nieminen, Mikko Moilanen, Sirpa Piirainen. (2007). Phosphorus allocation in surface soil of two drained peatland forests following wood and peat ash application – why effective adsorption on low sorptive soils? Silva Fennica vol. 41 no. 3 article id 280. https://doi.org/10.14214/sf.280
Fertilization of drained peatland forests with wood ash and different commercial phosphorus fertilizers (calcium phosphates) generally give similar stand growth responses. However, it has been shown that use of calcium phosphate fertilizers generally lead to highly increased P release to recipient water courses. On the other hand, no corresponding release has been reported after ash fertilization. Soil samples from the surface peats from a nutrient poor and a fertile drained peatland site were collected before and 1–4 years after application of five different types of ash products. The changes over time in the different chemical forms of P in the substrate were studied. The results indicated that the reason for the low liability to leaching of ash fertilizers was that significant amounts of P are adsorbed by Al and Fe during weathering of the ash fertilizers. However, further studies are needed to clarify whether the adsorption of P occurs with the Al and Fe of the ash or the native Al and Fe compounds present in soil before ash fertilization.
  • Nieminen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: mika.nieminen@metla.fi (email)
  • Moilanen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Piirainen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 295, category Research article
Pekka Kaitaniemi, Janne Riihimäki, Julia Koricheva, Harri Vehviläinen. (2007). Experimental evidence for associational resistance against the European pine sawfly in mixed tree stands. Silva Fennica vol. 41 no. 2 article id 295. https://doi.org/10.14214/sf.295
This study examined whether the saplings of Scots pine (Pinus sylvestris) exhibit associational resistance against the European pine sawfly Neodiprion sertifer (Hymenoptera, Diprionidae) when grown in a mixture with 50% silver birch (Betula pendula). The number of sawflies on pine trees in pure and mixed stands was manipulated at two experimental sites during two years. Survival of larvae and eggs was monitored, and the numbers of presumed sawfly predators were counted. A lower proportion of sawfly larvae and eggs survived on pines grown in the mixture with birch as compared with pure pine stands. Lower survival of sawfly larvae in the mixed stands was associated with the higher abundance of ants in these stands. The numbers of other sawfly predators (e.g. spiders and predatory heteropterans) differed between the study sites and were negatively associated with the presence of ants, which suggests possible interference between these groups. Although sawfly survival was lower on pines in the mixed stands, providing evidence of associational resistance, a related study shows the same trees had a higher number of ant-tended aphid colonies as compared with pines in the pure stands. Therefore, instead of considering resistance against individual herbivore species, it seems more practical to use associational resistance as a trait representing the resistance of larger systems, such as whole tree stands, against the total damage caused by herbivores in general.
  • Kaitaniemi, Hyytiälä Forestry Field Station, University of Helsinki, Hyytiäläntie 124, FI-35500 Korkeakoski, Finland ORCID ID:E-mail:
  • Riihimäki, Section of Ecology, Department of Biology, University of Turku, FI-20014 Turku, Finland ORCID ID:E-mail:
  • Koricheva, School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey, TW20 0EX, UK ORCID ID:E-mail:
  • Vehviläinen, Section of Ecology, Department of Biology, University of Turku, FI-20014 Turku, Finland ORCID ID:E-mail:
article id 292, category Research article
Sanna Susiluoto, Frank Berninger. (2007). Interactions between morphological and physiological drought responses in Eucalyptus microtheca. Silva Fennica vol. 41 no. 2 article id 292. https://doi.org/10.14214/sf.292
We studied the response of Eucalyptus microtheca to drought in a greenhouse experiment. As a result of the drought the growth of the seedlings decreased and allocation patterns changed so that allocation to the roots increased. However, changes in photosynthesis and stomatal conductance under drought were rather modest. We showed, using chlorophyll fluorescence and measurements of photosynthesis under high CO2 that the biochemical capacity of photosynthesis increased under drought. The results suggest that changes in root/shoot ratio are the primary reactions that initiate a series of compensatory reactions that mitigate the effects of drought in Eucalyptus microtheca.
  • Susiluoto, University of Helsinki, Department of Forest Ecology, PL 27, 00014 University of Helsinki, Finland ORCID ID:E-mail: sannamaija.susiluoto@helsinki.fi (email)
  • Berninger, Departement des Sciences biologiques, Université du Québec à Montréal, CP 8888 Succ Centre Ville, Montreal, Canada ORCID ID:E-mail:
article id 292, category Research article
Sanna Susiluoto, Frank Berninger. (2007). Interactions between morphological and physiological drought responses in Eucalyptus microtheca. Silva Fennica vol. 41 no. 2 article id 292. https://doi.org/10.14214/sf.292
We studied the response of Eucalyptus microtheca to drought in a greenhouse experiment. As a result of the drought the growth of the seedlings decreased and allocation patterns changed so that allocation to the roots increased. However, changes in photosynthesis and stomatal conductance under drought were rather modest. We showed, using chlorophyll fluorescence and measurements of photosynthesis under high CO2 that the biochemical capacity of photosynthesis increased under drought. The results suggest that changes in root/shoot ratio are the primary reactions that initiate a series of compensatory reactions that mitigate the effects of drought in Eucalyptus microtheca.
  • Susiluoto, University of Helsinki, Department of Forest Ecology, PL 27, 00014 University of Helsinki, Finland ORCID ID:E-mail: sannamaija.susiluoto@helsinki.fi (email)
  • Berninger, Departement des Sciences biologiques, Université du Québec à Montréal, CP 8888 Succ Centre Ville, Montreal, Canada ORCID ID:E-mail:
article id 317, category Research article
Erik Eriksson, Tord Johansson. (2006). Effects of rotation period on biomass production and atmospheric CO2 emissions from broadleaved stands growing on abandoned farmland. Silva Fennica vol. 40 no. 4 article id 317. https://doi.org/10.14214/sf.317
The growth rates and carbon stocks of unthinned young and mature stands of broadleaved trees growing on abandoned farmland were determined to assess whether their management regimes should involve short (15-year) or long (45-year) rotations to maximize biomass production and reductions of CO2 emissions. Dry mass production and mean annual increment (MAI) were calculated for 28 young stands and 65 mature stands of European aspen (Populus tremula L.), common alder (Alnus glutinosa (L.) Gaertn.), grey alder (Alnus incana (L.) Moench.), silver birch (Betula pendula Roth) and downy birch (Betula pubescens Ehrh.) ranging in latitude from 57° to 63° N in Sweden. The potential for using biomass from the stands to replace coal as a fuel and to store carbon was then evaluated both in short and long rotation scenarios. The results indicate that long rotations are beneficial if the objective is to maximize the average carbon stock in biomass. If, on the other hand, the intention is to optimize reductions in atmospheric CO2 emissions, rotations should be short for aspen, silver birch and grey alder stands. For downy birch and common alder, the MAI was higher for the mature stands than the young stands, indicating that in these species the mature stands are superior for both storing carbon and replacing fossil fuel. Stands of broadleaved trees grown to produce biofuel on abandoned farmland should be established on fertile soils to promote high MAI. If the MAI is low, the rotation period should be long to maximize the average carbon stock.
  • Eriksson, SLU, Dept of Bioenergy, P.O. Box 7061, SE-750 07 Uppsala, Sweden ORCID ID:E-mail:
  • Johansson, SLU, Dept of Bioenergy, P.O. Box 7061, SE-750 07 Uppsala, Sweden ORCID ID:E-mail:
article id 315, category Research article
Lauri Korhonen, Kari T. Korhonen, Miina Rautiainen, Pauline Stenberg. (2006). Estimation of forest canopy cover: a comparison of field measurement techniques. Silva Fennica vol. 40 no. 4 article id 315. https://doi.org/10.14214/sf.315
Estimation of forest canopy cover has recently been included in many forest inventory programmes. In this study, after discussing how canopy cover is defined, different ground-based canopy cover estimation techniques are compared to determine which would be the most feasible for a large scale forest inventory. Canopy cover was estimated in 19 Scots pine or Norway spruce dominated plots using the Cajanus tube, line intersect sampling, modified spherical densiometer, digital photographs, and ocular estimation. The comparisons were based on the differences in values acquired with selected techniques and control values acquired with the Cajanus tube. The statistical significance of the differences between the techniques was tested with the nonparametric Kruskall-Wallis analysis of variance and multiple comparisons. The results indicate that different techniques yield considerably different canopy cover estimates. In general, labour intensive techniques (the Cajanus tube, line intersect sampling) provide unbiased and more precise estimates, whereas the estimates provided by fast techniques (digital photographs, ocular estimation) have larger variances and may also be seriously biased.
  • Korhonen, University of Joensuu, P.O. Box 68, FI-68101 Joensuu, Finland ORCID ID:E-mail: lauri.korhonen@joensuu.fi (email)
  • Korhonen, University of Joensuu, P.O. Box 68, FI-68101 Joensuu, Finland ORCID ID:E-mail:
  • Rautiainen, University of Joensuu, P.O. Box 68, FI-68101 Joensuu, Finland ORCID ID:E-mail:
  • Stenberg, University of Joensuu, P.O. Box 68, FI-68101 Joensuu, Finland ORCID ID:E-mail:
article id 315, category Research article
Lauri Korhonen, Kari T. Korhonen, Miina Rautiainen, Pauline Stenberg. (2006). Estimation of forest canopy cover: a comparison of field measurement techniques. Silva Fennica vol. 40 no. 4 article id 315. https://doi.org/10.14214/sf.315
Estimation of forest canopy cover has recently been included in many forest inventory programmes. In this study, after discussing how canopy cover is defined, different ground-based canopy cover estimation techniques are compared to determine which would be the most feasible for a large scale forest inventory. Canopy cover was estimated in 19 Scots pine or Norway spruce dominated plots using the Cajanus tube, line intersect sampling, modified spherical densiometer, digital photographs, and ocular estimation. The comparisons were based on the differences in values acquired with selected techniques and control values acquired with the Cajanus tube. The statistical significance of the differences between the techniques was tested with the nonparametric Kruskall-Wallis analysis of variance and multiple comparisons. The results indicate that different techniques yield considerably different canopy cover estimates. In general, labour intensive techniques (the Cajanus tube, line intersect sampling) provide unbiased and more precise estimates, whereas the estimates provided by fast techniques (digital photographs, ocular estimation) have larger variances and may also be seriously biased.
  • Korhonen, University of Joensuu, P.O. Box 68, FI-68101 Joensuu, Finland ORCID ID:E-mail: lauri.korhonen@joensuu.fi (email)
  • Korhonen, University of Joensuu, P.O. Box 68, FI-68101 Joensuu, Finland ORCID ID:E-mail:
  • Rautiainen, University of Joensuu, P.O. Box 68, FI-68101 Joensuu, Finland ORCID ID:E-mail:
  • Stenberg, University of Joensuu, P.O. Box 68, FI-68101 Joensuu, Finland ORCID ID:E-mail:
article id 314, category Research article
Yuhua Wang, Helena Korpelainen, Chunyang Li. (2006). Microsatellite polymorphism in the edaphic spruce, Picea asperata, originating from the mountains of China. Silva Fennica vol. 40 no. 4 article id 314. https://doi.org/10.14214/sf.314
Microsatellite variation of Picea asperata Mast. originating from the mountains of China was investigated by analyzing variation at seven SSR loci in 250 individuals representing ten populations. A fair degree of genetic diversity and considerable population subdivision occurred with the mean gene diversity (H) of 0.707, and genetic distances among populations varying between 0.121 and 0.224 (FST) and between 0.100 and 0.537 (RST). However, inter-population genetic distances showed no correlation with geographic distances between the population sites. This ruled out a simple isolation by distance model and suggested that migration does not have a great impact. In fact, the amount of gene flow, detected using private alleles, was very low, equaling only 0.753. Allele permutation tests revealed that stepwise-like mutations, coupled with genetic drift, could contribute to population differentiation. Moreover, significant genetic differences between populations were detected at most loci. The results indicate that natural selection, presumably through environmental stress, may be one of the main factors causing micro-geographical differentiation in the genetic structure of P. asperata. Based on SSR genotypes, 70% of the 250 individuals were correctly classified into their sites of origin. This suggests that microsatellites (SSRs) are effective in distinguishing genotypes of P. asperata originating from diverse eco-geographical sites in China.
  • Wang, Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu 610041, China; Graduate School of the Chinese Academy of Sciences, Beijing 100039, China ORCID ID:E-mail:
  • Korpelainen, Department of Applied Biology, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Li, Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu 610041, China ORCID ID:E-mail: licy@cib.ac.cn (email)
article id 314, category Research article
Yuhua Wang, Helena Korpelainen, Chunyang Li. (2006). Microsatellite polymorphism in the edaphic spruce, Picea asperata, originating from the mountains of China. Silva Fennica vol. 40 no. 4 article id 314. https://doi.org/10.14214/sf.314
Microsatellite variation of Picea asperata Mast. originating from the mountains of China was investigated by analyzing variation at seven SSR loci in 250 individuals representing ten populations. A fair degree of genetic diversity and considerable population subdivision occurred with the mean gene diversity (H) of 0.707, and genetic distances among populations varying between 0.121 and 0.224 (FST) and between 0.100 and 0.537 (RST). However, inter-population genetic distances showed no correlation with geographic distances between the population sites. This ruled out a simple isolation by distance model and suggested that migration does not have a great impact. In fact, the amount of gene flow, detected using private alleles, was very low, equaling only 0.753. Allele permutation tests revealed that stepwise-like mutations, coupled with genetic drift, could contribute to population differentiation. Moreover, significant genetic differences between populations were detected at most loci. The results indicate that natural selection, presumably through environmental stress, may be one of the main factors causing micro-geographical differentiation in the genetic structure of P. asperata. Based on SSR genotypes, 70% of the 250 individuals were correctly classified into their sites of origin. This suggests that microsatellites (SSRs) are effective in distinguishing genotypes of P. asperata originating from diverse eco-geographical sites in China.
  • Wang, Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu 610041, China; Graduate School of the Chinese Academy of Sciences, Beijing 100039, China ORCID ID:E-mail:
  • Korpelainen, Department of Applied Biology, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Li, Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu 610041, China ORCID ID:E-mail: licy@cib.ac.cn (email)
article id 335, category Research article
Markus Holopainen, Mervi Talvitie. (2006). Effect of data acquisition accuracy on timing of stand harvests and expected net present value. Silva Fennica vol. 40 no. 3 article id 335. https://doi.org/10.14214/sf.335
Modern remote sensing provides cost-efficient spatial digital data that are more accurate than before. However, the influence of increased accuracy and cost-efficiency on simulations of forest management planning has not been evaluated. The aim of the present study was to analyse the effect of data acquisition accuracy on standwise forest inventory by comparing the accuracy and cost of traditional compartmentwise inventory methods with 2D and 3D measurements of digital aerial photographs and airborne laser scanning. Comparison was based on the expected net present value (NPV), i.e. economic losses that consisted of the inventory costs and incorrect timings of treatments. The reference data, totalling 700 ha, were measured from Central Park in the city of Helsinki, Finland. The data were simulated to final cut with a MOTTI simulator, which is a stand-level analysis tool that can be used to assess the effects of alternative forest management practices on growth and timber yield. The results showed that when inventory costs were not considered there were no significant differences between the expected NPV losses in 3D measurements of digital aerial photographs, laser scanning and the compartmentwise method. When inventory costs were taken into account, the compartmentwise method was still the most efficient inventory method in the study area. Forest inventories, however, are usually directed to larger areas when the costs per hectare of remote-sensing methods decrease. As a result of better accuracies, 3D and compartmentwise methods always produce better results than the 2D method when NPV losses are accounted. Simulations of this type are based on the accuracies and costs of the 3D data available today, assuming that the data can be used in tree-level measurements.
  • Holopainen, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: markus.holopainen@helsinki.fi (email)
  • Talvitie, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 335, category Research article
Markus Holopainen, Mervi Talvitie. (2006). Effect of data acquisition accuracy on timing of stand harvests and expected net present value. Silva Fennica vol. 40 no. 3 article id 335. https://doi.org/10.14214/sf.335
Modern remote sensing provides cost-efficient spatial digital data that are more accurate than before. However, the influence of increased accuracy and cost-efficiency on simulations of forest management planning has not been evaluated. The aim of the present study was to analyse the effect of data acquisition accuracy on standwise forest inventory by comparing the accuracy and cost of traditional compartmentwise inventory methods with 2D and 3D measurements of digital aerial photographs and airborne laser scanning. Comparison was based on the expected net present value (NPV), i.e. economic losses that consisted of the inventory costs and incorrect timings of treatments. The reference data, totalling 700 ha, were measured from Central Park in the city of Helsinki, Finland. The data were simulated to final cut with a MOTTI simulator, which is a stand-level analysis tool that can be used to assess the effects of alternative forest management practices on growth and timber yield. The results showed that when inventory costs were not considered there were no significant differences between the expected NPV losses in 3D measurements of digital aerial photographs, laser scanning and the compartmentwise method. When inventory costs were taken into account, the compartmentwise method was still the most efficient inventory method in the study area. Forest inventories, however, are usually directed to larger areas when the costs per hectare of remote-sensing methods decrease. As a result of better accuracies, 3D and compartmentwise methods always produce better results than the 2D method when NPV losses are accounted. Simulations of this type are based on the accuracies and costs of the 3D data available today, assuming that the data can be used in tree-level measurements.
  • Holopainen, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: markus.holopainen@helsinki.fi (email)
  • Talvitie, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 328, category Research article
Pedro J. Aphalo, Markku Lahti, Tarja Lehto, Tapani Repo, Aino Rummukainen, Hannu Mannerkoski, Leena Finér. (2006). Responses of silver birch saplings to low soil temperature. Silva Fennica vol. 40 no. 3 article id 328. https://doi.org/10.14214/sf.328
Two-year-old silver birch (Betula pendula) saplings were grown for a third growing season in controlled-environment rooms (dasotrons) at three soil temperatures (5, 10, and 20 °C). All trees grew the first flush of leaves, but the growth of the second flush was almost completely inhibited at the two lower temperatures. The dry weight of the second-flush leaves was 50 times larger at 20 °C than at 5 and 10 °C, with about 100 times more nitrogen. Root growth was less affected than shoot growth. Chlorophyll content, net assimilation rate and stomatal conductance were lower at low soil temperatures. The value of the cytoplasm resistance estimated from the electric impedance spectra was lower at 5 °C than at 10 or 20 °C. Leaf water potential was highest at the lowest soil temperature, and intercellular carbon dioxide concentration was only slightly lower in saplings growing in cooler soil. We conclude that the effect of long-term exposure to cold soil on net assimilation and growth was not caused by stomatal closure alone. It is likely to be additionally mediated by the limited nitrogen acquisition at the low soil temperatures, and perhaps additionally by some other factor. As the growth depression of aboveground parts in response to low soil temperature was more significant in silver birch than what has earlier been found in conifers, the relative changes in air and soil temperature may eventually determine whether birch will become more dominant in boreal forests with climate change.
  • Aphalo, University of Helsinki, Department of Biological and Environmental Sciences ORCID ID:E-mail:
  • Lahti, The Finnish Forest Research Institute ORCID ID:E-mail:
  • Lehto, University of Joensuu, Faculty of Forestry, Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: tarja.lehto@joensuu.fi (email)
  • Repo, The Finnish Forest Research Institute ORCID ID:E-mail:
  • Rummukainen, University of Joensuu, Faculty of Forestry, Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Mannerkoski, University of Joensuu, Faculty of Forestry, Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Finér, The Finnish Forest Research Institute ORCID ID:E-mail:
article id 346, category Research article
Tuomo Nurminen, Heikki Korpunen, Jori Uusitalo. (2006). Time consumption analysis of the mechanized cut-to-length harvesting system. Silva Fennica vol. 40 no. 2 article id 346. https://doi.org/10.14214/sf.346
The time consumption and productivity of harvesting are dependent on stand conditions, the operators’ skills, working techniques and the characteristics of the forestry machinery. Even if the basic methods and machine types of the cut-to-length harvesting system have not changed significantly in 10 to 15 years, improvements in the operators’ competence, technical solutions in forest machinery and changes in the working environment have undoubtedly taken place. In this study, the objective was to discover the special characteristics in the time consumption of mechanized cutting and forest haulage in Finnish conditions. The empirical time study was conducted with professional operators and medium-sized single-grip harvesters and forwarders in final fellings and thinnings in easy terrain in central Finland. The models for effective time consumption in the work phases and total productivity were formed. Stem size, tree species and bucking affected the cutting, whereas timber density on the strip road, the average driving distance, load capacity, wood assortment and the bunching result of the harvester operator had an effect on the forest haulage performance. The results may be used in simulations, cost calculations and education.
  • Nurminen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: tuomo.nurminen@joensuu.fi (email)
  • Korpunen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Uusitalo, Finnish Forest Research Institute, Parkano Research Unit, Kaironiementie 54, FI-39700 Parkano, Finland ORCID ID:E-mail:
article id 345, category Research article
Pekka Hyvönen, Perttu Anttila. (2006). Change detection in boreal forests using bi-temporal aerial photographs. Silva Fennica vol. 40 no. 2 article id 345. https://doi.org/10.14214/sf.345
Increased need for timely forest information is leading to continuous updating of stand databases. In continuous updating, stand attributes are estimated in the field after an operation and stored in databases. To find the changes caused by operations and forest damage, a semi-automatic method based on bi-temporal aerial photographs was developed. The test data were classified into three classes: No-change (952 stands), Moderate-change (163 stands) and Considerable-change (44 stands). The aerial photographs were acquired in years 2001 and 2004 with almost the same image specifications. Altogether 110 features at stand level were extracted and used in change detection analysis. The test data were classified with stepwise discriminant analysis. The overall accuracy of classification varied between 75.3 and 84.7%. The considerable changes were found without error, whereas the Moderate-change and No-change classes were often confused. However, 84.2% of thinned stands were classified correctly. The best accuracy in classification was obtained by using the histogram and textural features extracted from the original, uncorrected images. Radiometric correction did not improve the accuracy of classification. Soil type, characteristics of the growing stock and the location of a stand in an image were found to affect the change detection. Before the method can be applied operationally, issues related to, e.g., confusion between No-change and Moderate-change must be solved.
  • Hyvönen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: pekka.hyvonen@metla.fi (email)
  • Anttila, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 355, category Research article
Ilkka Korpela. (2006). Geometrically accurate time series of archived aerial images and airborne lidar data in a forest environment. Silva Fennica vol. 40 no. 1 article id 355. https://doi.org/10.14214/sf.355
Reconstructing three-dimensional structural changes in the forest over time is possible using archived aerial photographs and photogrammetric techniques, which have recently been introduced to a larger audience with the advent of digital photogrammetry. This paper explores the feasibility of constructing an accurate time-series of archived aerial photographs spanning 42 years using different types of geometric data and estimation methods for image orientation. A recent airborne laser scanning (lidar) data set was combined with the image block and assessed for geometric match. The results suggest that it is possible to establish the multitemporal geometry of an image block to an accuracy that is better than 0.5 m in 3D and constant over time. Even geodetic ground control points can be omitted from the estimation if the most recent images have accurate direct sensor orientation, which is becoming a standard technique in aerial photography. This greatly reduces the costs and facilitates the work. An accurate multitemporal image block combined with recent lidar scanning for the estimation of topography allows accurate monitoring and retrospective analysis of forest vegetation and management operations.
  • Korpela, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: ilkka.korpela@helsinki.fi (email)
article id 349, category Research article
Temel Sariyildiz, J. M. Anderson. (2006). Intra-specific variation in cell wall constituents of needle age classes of Pinus sylvestris in relation to soil fertility status in Southwest England. Silva Fennica vol. 40 no. 1 article id 349. https://doi.org/10.14214/sf.349
First, second and third year needles were collected from the same branches of young Scots pine trees growing on soils of two different status (high and low fertility sites) that varied in mineral nutrient concentrations and N mineralisation potential. All needle age classes were analysed for total carbon, acid detergent fibre (ADF), lignin, cellulose, phenylpropanoid derivatives (PPD) of lignin, sugar constituents of non-crystalline, hydrated cellulose and hemicellulose, and nutrient concentrations (N, P, K, Ca, Mg and Mn). Significant intra-specific variation in the litter quality variables in relation to soils of high and low fertility was found in the second and third year needles, whereas there were no differences in the other cell wall constituents and mineral elements of the first year needles. The second and third year needles from the low fertility soil contained higher concentrations of ADF, lignin, cellulose, sugar constituents of non-crystalline, hydrated cellulose and hemicellulose, and phenylpropanoid derivatives (PPD) of lignin, but lower concentrations of N, P and Mg than the same needles from the high fertility and fertilised soils. The results in the present study indicate that under different soil fertilities, needle age classes show significant variations in the cell wall constituents and mineral elements, and suggest that this can result in significant variation in litter quality and decomposition rates.
  • Sariyildiz, Kars Kafkas Üniversitesi, Artvin Orman Fakültesi, 08000 Artvin, Turkey ORCID ID:E-mail: t_sariyildiz@yahoo.com (email)
  • Anderson, Department of Biological Sciences, Hatherly Laboratories, University of Exeter, Exeter EX4 4PS, UK ORCID ID:E-mail:
article id 367, category Research article
Sakari Tuominen, Markus Haakana. (2005). Landsat TM imagery and high altitude aerial photographs in estimation of forest characteristics. Silva Fennica vol. 39 no. 4 article id 367. https://doi.org/10.14214/sf.367
Satellite sensor data have traditionally been used in multi-source forest inventory for estimating forest characteristics. Their advantages generally are large geographic coverage and large spectral range. Another remote sensing data source for forest inventories offering a large geographic coverage is high altitude aerial photography. In high altitude aerial photographs the spectral range is very narrow but the spatial resolution is high. This allows the extraction of texture features for forest inventory purposes. In this study we utilized a Landsat 7 ETM satellite image, a photo mosaic composed of high altitude panchromatic aerial photographs, and a combination of the aforementioned in estimating forest attributes for an area covering approximately 281 000 ha in Forestry Centre Häme-Uusimaa in Southern Finland. Sample plots of 9th National Forest Inventory (NFI9) were used as field data. In the estimation, 6 Landsat 7 ETM image channels were used. For aerial photographs, 4 image channels were composed from the spectral averages and texture features. In combining both data sources, 6 Landsat channels and 3 aerial image texture channels were selected for the analysis. The accuracy of forest estimates based on the Landsat image was better than that of estimates based on high altitude aerial photographs. On the other hand, using the combination of Landsat ETM spectral features and textural features on high altitude aerial photographs improved the estimation accuracy of most forest attributes.
  • Tuominen, Finnish Forest Research Institute, Unioninkatu 40 A, FI-00170 Helsinki, Finland ORCID ID:E-mail: sakari.tuominen@metla.fi (email)
  • Haakana, Finnish Forest Research Institute, Unioninkatu 40 A, FI-00170 Helsinki, Finland ORCID ID:E-mail:
article id 372, category Research article
Ulf Sikström. (2005). Pre-harvest soil acidification, liming or N fertilization did not significantly affect the survival and growth of young Norway spruce. Silva Fennica vol. 39 no. 3 article id 372. https://doi.org/10.14214/sf.372
Acidification, liming, and N fertilization affect a number of soil properties. Such changes may have an impact on forest regeneration and yield. The aim of this study was to investigate the survival and growth of Picea abies (L.) Karst. planted on plots that had been acidified (in 12 annual treatments totalling 600 or 1200 kg S ha–1 in the form of elemental sulphur), limed (12 x 500 = 6000 kg lime ha–1 in the form of CaCO3) or N-fertilized (3 x 200 = 600 kg N ha–1 in the form of urea) prior to harvest. Trees growing on plots treated with a combination of the N plus the lower S application were also tested. None of the treatments, applied in three replicate stands, significantly influenced either survival or growth of Picea abies trees during the first 11 growing seasons after planting.
  • Sikström, SkogForsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: ulf.sikstrom@skogforsk.se (email)
article id 413, category Research article
Mika Nieminen, Timo Penttilä. (2004). Inorganic and organic phosphorus fractions in peat from drained mires in northern Finland. Silva Fennica vol. 38 no. 3 article id 413. https://doi.org/10.14214/sf.413
Soil samples from 15 eutrophic, 26 herb-rich, 15 tall-sedge, and 11 low-sedge drained peatland sites were analysed for easily soluble and aluminum, iron, and calcium bound phosphorus (P) using the Chang and Jackson sequential fractionation method. Compared to earlier investigations, where only total and easily soluble P contents (e.g. NH4OAc or dilute H2SO4 extractable P) in peat have been analysed, significantly higher differences between sites were observed. The eutrophic sites were characterized by four to six-fold greater Ca-bound organic P and two to three-fold greater Ca-bound inorganic P contents than on the other three site type groups, whereas the average Al-bound inorganic P content of the eutrophic sites was only one-third of that at the other site types. Substantial differences between sites were also observed for Fe-bound inorganic P, i.e. two to four-fold greater Fe-P contents were measured at the herb-rich sites compared with the other three site type groups. The stand volume growth in the 67 studied drained peatland sites correlated significantly with Al-bound organic P and Fe-bound inorganic and organic P. The study showed that a detailed fractionation and discrimination of different forms of soil P is important in increasing the understanding of the relationship between P availability and vegetation community types and stand growth on drained peatlands.
  • Nieminen, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: mika.nieminen@metla.fi (email)
  • Penttilä, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 495, category Research article
Christopher Dean. (2003). Calculation of wood volume and stem taper using terrestrial single-image close-range photogrammetry and contemporary software tools. Silva Fennica vol. 37 no. 3 article id 495. https://doi.org/10.14214/sf.495
A method of estimating trunk and branch volumes of single trees is presented that uses a combination of elementary field measurements, terrestrial photography, image rectification and on-screen digitising using commercial software packages and automated volume calculation. The method is applicable to a variety of different sized trees in situations where the trunks are clearly visible. Results for taper measurement and wood volume calculation are presented for Eucalyptus regnans F. von Muell., Sequoiadendron giganteum (Lindley) Buchholz and Quercus robur L. Branch allometrics are provided for E. regnans. The largest errors arose from field observations. If the trees are asymmetrical in cross-section (e.g. due to irregular buttressing or forked stems), or if there is no vantage point perpendicular to the direction of lean, then photographs from more than one side are recommended. Accuracy and precision of geometric reproduction by the image rectification process, and the volume calculation, were tested using mathematically generated tree components. The errors in the branch volumes of the virtual tree showed complex trends due to interacting factors. Volumes were underestimated by an average 0.5% for stems and 4% for branches. Due to the area deficit resulting from non-circular cross-sections of the buttress, overestimation of stem volumes could be as high as 10% on average for mature trees. However, the area deficit was known for E. regnans and incorporated into the volume calculation. The underestimation of volumes would help counteract over-estimation due to the area deficit. The application of this method to carbon accounting in forests and woodlands is explained.
  • Dean, CRC for Greenhouse Accounting, The Australian National University, GPO Box 475, Canberra, ACT 2601, Australia ORCID ID:E-mail: cdean@rsbs.anu.edu.au (email)
article id 493, category Research article
Göran Rune. (2003). Slits in container wall improve root structure and stem straightness of outplanted Scots pine seedlings. Silva Fennica vol. 37 no. 3 article id 493. https://doi.org/10.14214/sf.493
Root structure and basal sweep were measured on 6-year-old Scots pine (Pinus sylvestris L.) trees at two sites with different soil fertility. Each site was planted with seedlings of identical origin after nursery cultivation in either solidwall container types with vertical ribs or in slitwall container types. Neither container design nor container volume affected tree height or stem diameter on the two sites. The transversal area of lateral roots was larger than the transversal area of bottom roots for the two container types at both sites. The proportion of bottom root transversal area to the total root transversal area was larger in the seedlings growing on the low fertility site than in those growing in the high fertility site for both container types. Seedlings cultivated in slitwall containers had a larger root area in proportion to stem diameter and had less root spiralling compared to the trees cultivated in solidwall containers. At the high fertility site, trees from the slitwall container type had straighter stem bases than seedlings grown in solidwall containers. At the low fertility site, differences in basal sweep formation were small between the container types. Reasons for this are discussed.
  • Rune, Dalarna University, Department of Forestry and Wood Technology, SE-776 98 Garpenberg, Sweden ORCID ID:E-mail: gru@du.se (email)
article id 498, category Research article
Slobodan B. Mickovski, A. Roland Ennos. (2003). Anchorage and asymmetry in the root system of Pinus peuce. Silva Fennica vol. 37 no. 2 article id 498. https://doi.org/10.14214/sf.498
The relationship between the anchorage mechanics and root architecture of Pinus peuce was investigated by carrying out winching tests and examining excavated root systems of 20 mature trees. The root system was dominated by 6.1±1.3 lateral roots, more than 70% of the lateral root cross sectional area (CSA) being distributed in the uppermost 10 cm of soil. Anchorage strength was related to the size of the tree and CSA. The overturning moment of trees was proportional to the diameter at breast height (DBH) to the power of 1.6. The trees exhibited significant asymmetry in anchorage rigidity, but although there was clustering of lateral roots in a preferred direction the root asymmetry was not significantly correlated with the asymmetry in anchorage rigidity, suggesting that much of the anchorage is provided by tap and sinker roots, rather than the laterals. However, the major laterals showed dorsoventral eccentricity, the more eccentric ones being those that were distributed closer to the soil surface and which pointed perpendicular to the direction of greatest resistance. This suggests that this is a result of thigmomorphogenetic effects. These results are compared with those for the related P. sylvestris and suggest that the assimilation and anchorage characteristics of root systems are controlled independently of each other.
  • Mickovski, School of Biological Sciences, University of Manchester, 3.614 Stopford Building, Manchester M13 9PT, UK ORCID ID:E-mail:
  • Ennos, School of Biological Sciences, University of Manchester, 3.614 Stopford Building, Manchester M13 9PT, UK ORCID ID:E-mail: roland.ennos@man.ac.uk (email)
article id 516, category Research article
Celeste Lacuna-Richman. (2003). Ethnicity and the utilization of non-wood forest products: findings from three Philippine villages. Silva Fennica vol. 37 no. 1 article id 516. https://doi.org/10.14214/sf.516
The utilization and trade of non-wood forest products in three villages in the Philippines were compared in this study. Two villages were situated close to each other on the Island of Palawan. The Tagbanua, an indigenous people, inhabited one village; migrants from the Visayas Region of the Philippines populated the other. The third village is located on the Island of Leyte, in the Visayas Region, populated by native Visayan settlers. There was no significant difference in the number of NWFPs utilized by the indigenous people and the migrants. However, there was a wide disparity in income between the two groups, with migrants earning more, partly due to the marketing of commercial NWFPs. This gap could be decreased by fairer trading practices that are dependent in part on better educational opportunities, land rights, legal assistance and access to markets for the Tagbanua. Specific socioeconomic characteristics, such as the presence of a hunter within the household and size of the family were found to have a positive correlation with the use of NWFPs in some study villages. Income and the food expenditure of the household were inversely related with the use of NWFPs in the native Visayan village.
  • Lacuna-Richman, Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail: celeste.lacuna-richman@forest.joensuu.fi (email)
article id 533, category Research article
Anna Liisa Ruotsalainen, Juha Tuomi, Henry Väre. (2002). A model for optimal mycorrhizal colonization along altitudinal gradients. Silva Fennica vol. 36 no. 3 article id 533. https://doi.org/10.14214/sf.533
Mycorrhizal associations are generally favourable for vascular plants in nutrient-poor conditions. Still, non-mycorrhizal plants are common in high arctic and alpine areas, which are often poor in nitrogen and phosphorus. The relative proportion of mycorrhizal plants has been found to decrease along with increasing altitude, suggesting that the advantage of the mycorrhizal symbiosis may change along an altitudinal gradient. This may be related to the environmental factors that possibly constrain the amount of photosynthesized carbon to be shared with mycorrhizal fungi. We propose a simple optimization model for root colonization by fungal symbionts and analyze the advantages of mycorrhizas in relation to the nutrient use efficiency of photosynthesis (PNUE), the kinetics of nutrient uptake and the soil nutrient levels. Our model suggests that mycorrhizas are not usually favoured at low PNUE values. At low nutrient levels, mycorrhizas may be advantageous if they have a lower threshold concentration of nutrient uptake (xmin) compared to non-mycorrhizal roots. If mycorrhizal roots have a higher maximum capacity of nutrient uptake (Vmax), mycorrhizas can be favourable for the host plant even at relatively low nutrient concentrations and at relatively low PNUE. Consequently, the possible patterns along altitudinal gradients essentially depend on PNUE. If the soil nutrient concentration is constant and PNUE decreases, the advantage of mycorrhizal symbiosis declines independently of the nutrient uptake kinetics. If PNUE remains constant and the soil nutrient concentration decreases along with increasing altitude, the emerging colonization pattern (either increasing, decreasing or intermediate) depends on the nutrient uptake kinetics. Additionally, if both PNUE and the soil nutrient concentration decrease, several patterns may emerge, depending on the nutrient uptake kinetics.
  • Ruotsalainen, Department of Biology, Botanical Museum, Box 3000, FIN-90014 University of Oulu, Finland ORCID ID:E-mail: annu.ruotsalainen@oulu.fi (email)
  • Tuomi, Department of Biology, Box 3000, FIN-90014 University of Oulu, Finland ORCID ID:E-mail:
  • Väre, Botanical Museum, Finnish Museum of Natural History, Box 7, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 529, category Research article
Tuula Aalto, Pertti Hari, Timo Vesala. (2002). Comparison of an optimal stomatal regulation model and a biochemical model in explaining CO2 exchange in field conditions. Silva Fennica vol. 36 no. 3 article id 529. https://doi.org/10.14214/sf.529
Gas exchange of Pinus sylvestris L. was studied in subarctic field conditions. Aspects on optimal control of the gas exchange were examined using approach by Hari et al. (Tree Phys. 2: 169–175, 1986). Biochemical model by Farquhar et al. (Planta 149: 78–90, 1980) was utilized to describe the photosynthetic production rate of needles. The model parameters were determined from field measurements. The results from the optimization approach and biochemical model were compared and their performance was found quite similar in terms of R2 calculated using measured exchange rates (0.89 for optimization model and 0.85 for biochemical model). Minor differences were found in relation to responses to intercellular carbon dioxide concentration and temperature.
  • Aalto, Finnish Meteorological Institute, Air Quality Research, Sahaajankatu 20 E, FIN-00810 Helsinki, Finland ORCID ID:E-mail: tuula.aalto@fmi.fi (email)
  • Hari, University of Helsinki, Dept. of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Vesala, University of Helsinki, Dept. of Physics, P.O. Box 64, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 544, category Research article
Perttu Anttila. (2002). Updating stand level inventory data applying growth models and visual interpretation of aerial photographs. Silva Fennica vol. 36 no. 2 article id 544. https://doi.org/10.14214/sf.544
In this study two procedures for updating stand level inventory data were developed and tested. The development of the growing stock of 62 stands over 12 years was simulated in the MELA stand simulator with no prior information of rapid changes, such as clear-cuttings. The acceptability of the simulation was decided standwise with visual interpretation of aerial false-colour photographs. If the simulated data were not accepted, new stand attributes were assessed with photo interpretation in procedure 1. In procedure 2, on the other hand, it was possible to utilise old management proposals. In case a cutting or other operation had been proposed and it looked like the operation had been realised, the interpreters accepted the proposal. Otherwise the last implemented operation and implementation year were interpreted. In case no operation had been carried out during the updating period but the growth model updated data were not acceptable, the same stand characteristics were estimated as in procedure 1. Stands where a proposal had been accepted or an operation interpreted were later updated again in MELA so that the program simulated the operations. The Root Mean Squared Errors of stem volume were 62 and 57 m3 per ha (34 and 30%) with procedures 1 and 2. With procedure 2 the accuracy of updating was comparable with a stand level field inventory carried out in the study area. The productivity of the photo interpretation procedures was 57 and 84 ha per h, respectively, whereas the productivity of a field inventory has been 3.3–5 ha per h.
  • Anttila, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: perttu.anttila@joensuu.fi (email)
article id 541, category Research article
Azim U. Mallik, F. Wayne Bell, Yanli Gong. (2002). Effectiveness of delayed brush cutting and herbicide treatments for vegetation control in a seven-year-old jack pine plantation in northwestern Ontario, Canada. Silva Fennica vol. 36 no. 2 article id 541. https://doi.org/10.14214/sf.541
Efficacy of three conifer release treatments, i) single application of glyphosate (Vision™) herbicide, ii) multiple application of glyphosate herbicide, and iii) motor-manual brush cutting for controlling competing plants, particularly trembling aspen (Populus tremuloides), pin cherry (Prunus pensylvanica), green alder (Alnus viridis spp. crispa), and beaked hazel (Corylus cornuta spp. cornuta), was studied in a seven-year-old jack pine (Pinus banksiana) plantation in northwestern Ontario, Canada. The single and multiple glyphosate applications were equally effective in controlling trembling aspen and pin cherry, causing over 90% stem mortality. The brushsaw treatment caused an initial decrease followed by an increase in stem density of these two species. A high degree of stem thinning by natural mortality in the untreated control plots was observed in trembling aspen (23–46%) and pin cherry (41–69%) over four years. As with trembling aspen and pin cherry, stem density of green alder and beaked hazel initially decreased and then increased following the brushsaw treatment, mainly due to resprouting. Stem mortality in green alder and beaked hazel was 45% and 97%, respectively, two years after the operational glyphosate treatment. Competition index (CI) was low (mean CI = 52, ranging from 18 to 115) in all the plots including the untreated control. There was a significant increase in basal diameter of jack pine in the brushsaw and herbicide-treated plots compared to the control three years after the treatments. Jack pine seedlings in the brushsaw and glyphosate treated plots were taller compared to that of control but differences were not significant. Lower species richness and diversity were recorded in the herbicide-treated plots compared to the brushsaw and control plots in the third growing season following treatment.
  • Mallik, Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada P7B 5E1 ORCID ID:E-mail: azim.mallik@lakeheadu.ca (email)
  • Bell, Ontario Forest Research Institute, Ontario Ministry of Natural Resources, Sault Ste. Marie, Ontario, Canada P6A 2E5 ORCID ID:E-mail:
  • Gong, Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada P7B 5E1 ORCID ID:E-mail:
article id 538, category Research article
Seppo Nevalainen. (2002). The incidence of Gremmeniella abietina in relation to topography in southern Finland. Silva Fennica vol. 36 no. 2 article id 538. https://doi.org/10.14214/sf.538
Field data of the 8th National Forest Inventory (NFI) from southern Finland and digital elevation models (DEMs) were used in this study. Damage due to Gremmeniella abietina increased slightly with an increase in absolute elevation in mineral soils. Severe damage increased almost linearly with an increase in elevation in mineral soil plots. The mean elevation in the tract area (the 7 km x 8 km area surrounding the plot) was more strongly correlated with the disease than the elevation of individual plots. The relative altitude of the plot was important: the disease was most severe in the plots situated lower than the mean elevation of the tract area, especially in the peatland plots. In this group, the damage increased linearly with an increase in absolute elevation. According to detailed DEMs in the most diseased areas, steepness of the slope was negatively correlated with the disease. The aspect of the slope had a weak influence. On mineral soils, the disease was most common in south-facing slopes. The microtopography was not as important for the disease occurrence as the relative elevation of the plot. The disease frequencies were very similarly related to the three most common types of surface features (channels, ridges and planar regions) within the 50-m scale. At the cell size of 100 metres, the disease was more common in channels than in ridges, except in mineral soil plots. Topographic variables only partly explained the regional patterns in the occurrence of this disease. The disease was frequent on upland areas, but, on the other hand, it was also common on lowland areas. The most diseased areas studied in detail differed very much from each other with respect to topography and the disease incidence.
  • Nevalainen, Finnish Forest Research Institute, Joensuu Research Centre, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail: seppo.nevalainen@metla.fi (email)
article id 577, category Research article
Jouni Siipilehto. (2001). Effect of weed control with fibre mulches and herbicides on the initial development of spruce, birch and aspen seedlings on abandoned farmland. Silva Fennica vol. 35 no. 4 article id 577. https://doi.org/10.14214/sf.577
Post-planting weed control methods on abandoned farmland were studied in three field trials in southern Finland using a completely randomized design with four treatments and 30 to 40 replications. Mulches of 60 x 60 cm [sheet mulch – strips of plane waste and plastic fibre, newspaper – waste paper slurry, wood chips, pure wood fibre slurry], herbicides [i.e. glyphosate or terbuthylazine alone or mixed and dichlobenile applied to 1 m2 spots] and hoeing treatments were compared to an untreated control plot. The study material consisted of two-year-old containerized aspen (Populus tremula L.), silver birch (Betula pendula (L.) Roth) and Norway spruce (Picea abies (L.) Karst.) seedlings planted in spring 1996. The ground vegetation was dominated by Elymys repens, Deschampsia cespitosa, Cirsium arvense and Epilobium angustifolium. Monitoring of the trials over a 3-year period showed a moderate effect of weed control, which varied according to the method used and by the crop species. Significant growth responses were found with herbicide in spruce, wood chips in spruce and birch and with sheet mulch in aspen seedlings. Sheet mulch also encouraged vole nesting thus increasing damages. Generally, slurry mulches proved to be insufficiently durable. Mulching had a clear insulating effect, which may increase the risk of winter drought.
  • Siipilehto, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: jouni.siipilehto@metla.fi (email)
article id 575, category Research article
Sylvie Mussche, Roeland Samson, Lieven Nachtergale, An De Schrijver, Raoul Lemeur, Noël Lust. (2001). A comparison of optical and direct methods for monitoring the seasonal dynamics of leaf area index in deciduous forests. Silva Fennica vol. 35 no. 4 article id 575. https://doi.org/10.14214/sf.575
During the 1996 growing season the seasonal dynamics of the Leaf Area Index (LAI) were determined by 3 different methods in two forest types: a mixed oak (Quercus robur L.) – beech (Fagus sylvatica L.) stand and an ash dominated (Fraxinus excelsior L.) stand. The results obtained from the two indirect methods, i.e. hemispherical photography and LAI-2000 Plant Canopy Analyser (Li-COR), were compared with the results of the direct measurement of litter fall collected in litter trap systems. In this study the direct method is considered to be the reference, giving the most accurate LAI-values. Both the hemispherical photography and the LAI-2000 PCA introduced an underestimation of LAI when the actual canopy leaf distribution in the crown layer deviates from a random distribution of leaf area in space as is found in the mixed oak/beech stand. However, when the condition of random leaf distribution is nearly fulfilled (ash stand), the LAI-2000 PCA gave LAI-values which were close to the results obtained from the direct method. Regression curves with R2 > 0.93 could be calculated for both indirect methods.
  • Mussche, Laboratory of Forestry, Ghent University, Geraardsbergse Steenweg 267, B-9090 Melle, Belgium ORCID ID:E-mail:
  • Samson, Laboratory of Plant Ecology, Ghent University, Coupure Links 653, B-9000 Gent, Belgium ORCID ID:E-mail:
  • Nachtergale, Laboratory of Forestry, Ghent University, Geraardsbergse Steenweg 267, B-9090 Melle, Belgium ORCID ID:E-mail:
  • De Schrijver, Laboratory of Forestry, Ghent University, Geraardsbergse Steenweg 267, B-9090 Melle, Belgium ORCID ID:E-mail: An.Deschrijver@rug.ac.be (email)
  • Lemeur, Laboratory of Plant Ecology, Ghent University, Coupure Links 653, B-9000 Gent, Belgium ORCID ID:E-mail:
  • Lust, Laboratory of Forestry, Ghent University, Geraardsbergse Steenweg 267, B-9090 Melle, Belgium ORCID ID:E-mail:
article id 590, category Research article
Anna Saarsalmi, Eino Mälkönen, Sirpa Piirainen. (2001). Effects of wood ash fertilization on forest soil chemical properties. Silva Fennica vol. 35 no. 3 article id 590. https://doi.org/10.14214/sf.590
The effects of wood ash fertilization on soil chemical properties were studied in three young Scots pine (Pinus sylvestris L.) plantations and a Norway spruce (Picea abies (L.) Karst.) plantation with different site fertility in southern Finland. The dose of 3 t ha–1 of loose wood ash was applied to 4 replicate plots (25 x 25 m) at each experiment. Humus layer and mineral soil samples were taken before the treatment and 7 and 16 years after wood ash application. Results showed that neutralization as well as fertilization effects of wood ash on forest soil were of long duration. An ash-induced pH increase of 0.6–1.0 pH units and exchangeable acidity (EA) decrease of 58–83% were detected in the humus layer 16 years after wood ash application. The decrease in acidity was most pronounced on the Calluna site with initially the lowest pH and highest EA. In the mineral soil the increase in pH was observed later than in the humus layer. After 16 years, the mineral soil pH was increased (0.2–0.3 pH units) on the Vaccinium and Myrtillus sites. A corresponding and in most cases a significant increase in the extractable Ca and Mg concentrations was detected in both the humus layer and in the mineral soil. Wood ash significantly increased the effective cation exchange capacity (CECe) and base saturation (BS) but decreased the concentration of exchangeable Al in both soil layers on all the sites. No response of N availability to wood ash application could be found.
  • Saarsalmi, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: anna.saarsalmi@metla.fi (email)
  • Mälkönen, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
  • Piirainen, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
article id 596, category Research article
Sakari Tuominen, Simo Poso. (2001). Improving multi-source forest inventory by weighting auxiliary data sources. Silva Fennica vol. 35 no. 2 article id 596. https://doi.org/10.14214/sf.596
A two-phase sampling design has been applied to forest inventory. First, a large number of first phase sample plots were defined with a square grid in a geographic coordinate system for two study areas of about 1800 and 4500 ha. The first phase sample plots were supplied by auxiliary data of Landsat TM and IRS-1C with principal component transformation for stratification and drawing the second phase sample (field sample). Proportional allocation was used to draw the second phase sample. The number of field sample plots in the two study areas was 300 and 380. The local estimates of five continuous forest stand variables, mean diameter, mean height, age, basal area, and stem volume, were calculated for each of the first phase sample plots. This was done separately by using one auxiliary data source at a time together with the field sample information. However, if the first phase sample plot for which the stand variables were to be estimated was also a field sample plot, the information of that field sample plot was eliminated according to the cross validation principle. This was because it was then possible to calculate mean square errors of estimates related to a specific auxiliary data source. The procedure produced as many estimates for each first phase sample plot and forest stand variable as was the number of auxiliary data sources, i.e. seven estimates: These were based on Landsat TM, IRS-1C, digitized aerial photos, ocular stereoscopic interpretation from aerial photographs, data from old forest inventory made by compartments, Landsat TM95–TM89 difference image and IRS96–TM95 difference image. The final estimates were calculated as weighted averages where the weights were inversely proportional to mean square errors. The alternative estimates were calculated by applying simple rules based on knowledge and the outliers were defined. The study shows that this kind of system for finding outliers for elimination and a weighting procedure improves the accuracy of stand variable estimation.
  • Tuominen, Finnish Forest Research Institute, Unioninkatu 40 A, FIN-00170 Helsinki, Finland ORCID ID:E-mail: sakari.tuominen@metla.fi (email)
  • Poso, Department of Forest Resource Management, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 591, category Research article
Qibin Yu. (2001). Can physiological and anatomical characters be used for selecting high yielding hybrid aspen clones? Silva Fennica vol. 35 no. 2 article id 591. https://doi.org/10.14214/sf.591
Stomatal, CO2 exchange parameters and several leaf and growth traits were recorded in a five-year-old hybrid aspen clone trial. The field trial consisted of four aspen hybrid clones (Populus tremula L. x P. tremuloides Michx.) and one local Populus tremula seedling source. The mean estimated height of hybrid aspen clones was 1.6 times higher than for P. tremula. Similarly, basal diameter was 1.5 times and breast diameter 1.8 times higher in the hybrids. Differences were observed for physiological and growth traits among hybrid clones and P. tremula, but, only stomatal characters of hybrid clones differed significantly from those in P. tremula. Hybrid clones had larger guard cells (22.9 mm) than P. tremula (19.2 mm), whereas P. tremula had a higher stomatal density (211.3/mm2) than the hybrid clones (164.4/mm2). Among four hybrid clones, net photosynthesis was strongly correlated with foliar nitrogen. Height correlated significantly with foliar nitrogen, but negatively with leaf fresh weight, leaf dry weight and stomatal density. The results suggested that yield components could be controlled by many genes, specific to each clone. No single gas exchange or morphological variable can provide a reliable indicator of yield potential.
  • Yu, Department of Plant Biology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: qibin.yu@helsinki.fi (email)
article id 600, category Research article
Qibin Yu, P. M. A. Tigerstedt, Matti Haapanen. (2001). Growth and phenology of hybrid aspen clones (Populus tremula L. x Populus tremuloides Michx.). Silva Fennica vol. 35 no. 1 article id 600. https://doi.org/10.14214/sf.600
Height, basal diameter, diameter at breast height, bud burst, and leaf development were recorded in a 5-year-old hybrid aspen clonal trial. The field trial consisted of four aspen hybrid clones (Populus tremula x Populus tremuloides) and one local P. tremula seedling source. Phenological traits were observed in the 3rd year. Growth patterns were recorded during the 3rd and 4th years. Phenological traits were explored in relation to hybrid vigor expressed as growth traits. Differences were observed for phenological and growth traits among hybrid clones and P. tremula. The growth period varied from 143–158 days for the four hybrid clones, and was 112 days for P. tremula. The correlation between growth period and yield was highly significant. The annual growth rate of height for the hybrids was 4.2 cm per 7 days (2.4 for P. tremula) in the 3rd year and 6.4 cm per 7 days (2.9 for P. tremula) in the 4th year. After 5 years, mean estimated stem volume of the hybrids was 3.9 times that of P. tremula. Significant clone by year interaction was observed for height, diameter, and volume growth. The hybrid vigor seems to be mainly attributable to a longer growth period.
  • Yu, Department of Plant Biology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: qibin.yu@helsinki.fi (email)
  • Tigerstedt, Department of Plant Biology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Haapanen, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
article id 647, category Research article
Tapio Linkosalo. (1999). Regularities and patterns in the spring phenology of some boreal trees. Silva Fennica vol. 33 no. 4 article id 647. https://doi.org/10.14214/sf.647
Phenological time series of flowering and bud burst of Populus tremula (L.) and Betula sp., and the flowering of Pinus sylvestris (L.), Alnus glutinosa (L.) and Alnus incana (L.) were constructed from data collected in Finland during the period 1896–1955. The resulting combined time series were examined with two aims in mind: first, to determine the phenological regularities between different species and, second, to detect patterns of spring advancement over a geographically large area. The results indicate that the geographical pattern of spring advancement is rather uniform from year to year, and between different species. Furthermore, the mechanisms regulating the timing of phenological events in different species seem to function in a similar way, suggesting an unanimous optimal response to climatic conditions.
  • Linkosalo, University of Helsinki, Department of Forest Ecology, Unioninkatu 40 B, P.O. Box 24, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: tapio.linkosalo@helsinki.fi (email)
article id 647, category Research article
Tapio Linkosalo. (1999). Regularities and patterns in the spring phenology of some boreal trees. Silva Fennica vol. 33 no. 4 article id 647. https://doi.org/10.14214/sf.647
Phenological time series of flowering and bud burst of Populus tremula (L.) and Betula sp., and the flowering of Pinus sylvestris (L.), Alnus glutinosa (L.) and Alnus incana (L.) were constructed from data collected in Finland during the period 1896–1955. The resulting combined time series were examined with two aims in mind: first, to determine the phenological regularities between different species and, second, to detect patterns of spring advancement over a geographically large area. The results indicate that the geographical pattern of spring advancement is rather uniform from year to year, and between different species. Furthermore, the mechanisms regulating the timing of phenological events in different species seem to function in a similar way, suggesting an unanimous optimal response to climatic conditions.
  • Linkosalo, University of Helsinki, Department of Forest Ecology, Unioninkatu 40 B, P.O. Box 24, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: tapio.linkosalo@helsinki.fi (email)
article id 656, category Research article
Klaus Silfverberg, Markus Hartman. (1999). Effects of different phosphorus fertilisers on the nutrient status and growth of Scots pine stands on drained peatlands. Silva Fennica vol. 33 no. 3 article id 656. https://doi.org/10.14214/sf.656
The aim of the study was to compare the effects of phosphorus fertilisers of different solubility and different phosphorus doses. The material was collected from 8 field experiments situated on drained peatlands in southern and central Finland (60°–65°N). The sites were drained, oligotrophic pine fens and pine bogs, which had been fertilised between 1961 and 1977 with different combinations of N, K and P. In 1991–94 stand measurements and foliar and peat sampling were carried out on 162 sample plots. Apatite, rock phosphate and superphosphate affected basal area growth to a rather similar extent. However, apatite slightly surpassed superphosphate and rock phosphate at the end of the study period in two hollow-rich S. fuscum bogs. Higher doses of phosphorus did not significantly increase the basal area growth. The foliar phosphorus concentrations clearly reflected the effect of the P fertilisation. Especially on the pine bogs basic fertilisation with 66 kg P/ha maintained the needle phosphorus concentrations at a satisfactory level for more than 25 years after fertilisation. The amount of phosphorus in the 0–20 cm peat layer was not significantly increased either by basic fertilisation or refertilisation. The phosphorus reserves in the peat in the individual experiments were between 88 and 327 kg/ha. There was a strong correlation between the amounts of phosphorus and iron in the peat. Large amounts of iron in peat may reduce the solubility and availability of phosphorus. According to the foliar phosphorus concentrations in the basic-fertilised plots, the need for refertilisation seems to be unnecessary during the 25-year postfertilisation period at least. None of the basic fertilisation treatments seriously retarded the basal area growth compared to the refertilised treatments. There seems to be a greater shortage of potassium than of phosphorus, because the foliar potassium concentrations and the amounts of potassium in the 0–20 cm peat layer were very low in several of the experiments.
  • Silfverberg, The Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: klaus.silfverberg@metla.fi (email)
  • Hartman, The Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
article id 669, category Research article
Simo Poso, Guangxing Wang, Sakari Tuominen. (1999). Weighting alternative estimates when using multi-source auxiliary data for forest inventory. Silva Fennica vol. 33 no. 1 article id 669. https://doi.org/10.14214/sf.669
Five auxiliary data sources (Landsat TM, IRS-IC, digitized aerial photographs, visual photo-interpretation and old forest compartment information) applying three study areas and three estimators, two-phase sampling with stratification, the k nearest neighbors and regression estimator, were examined. Auxiliary data were given for a high number of sample plots, which are here called first phase sample plots. The plots were distributed using a systematic grid over the study areas. Some of the plots were then measured in the field for the necessary ground truth. Each auxiliary data source in combination with field sample information was applied to produce a specific estimator for five forest stand characteristics: mean diameter, mean height, age, basal area, and volume of the growing stock. When five auxiliary data sources were used, each stand characteristic and each first phase sample plot were supplied with five alternative estimates with three alternative estimators. Mean square errors were then calculated for each alternative estimator using the cross validation method. The final estimates were produced by weighting alternative estimates inversely according to the mean square errors related to the corresponding estimator. The result was better than the final estimate of any of the single estimators. The improvement over the best single estimate, as measured in mean square error, was 16.9% on average for all five forest stand characteristics. The improvement was fairly equal for all five forest stand characteristics. Only minor differences among the accuracies of the three alternative estimators were recorded.
  • Poso, Department of Forest Resource Management, P.O. Box 24 (Unioninkatu 40 B), FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: simo.poso@helsinki.fi (email)
  • Wang, Department of Forest Resource Management, P.O. Box 24 (Unioninkatu 40 B), FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Tuominen, Department of Forest Resource Management, P.O. Box 24 (Unioninkatu 40 B), FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 674, category Research article
Tuula Aalto. (1998). Carbon dioxide exchange of Scots pine shoots as estimated by a biochemical model and cuvette field measurements. Silva Fennica vol. 32 no. 4 article id 674. https://doi.org/10.14214/sf.674
A biochemical model was used to calculate CO2 fluxes to Scots pine shoots in two boreal measurement stations, Hyytiälä in southern Finland (61°51’N, 24°17’E) and Värriö in northern Finland (67°46’N, 29°35’E). The results of the model were compared with cuvette measurements performed in field conditions. A differential equation for change in gas concentration inside a closed cuvette was constructed and solved in order to obtain conductances and fluxes. The results were generally in a good agreement, the correlation coefficients varied from 0.74 to 0.95. Some discrepancies were also found. The model followed more intensively changes in temperature. This could be seen in northern Finland measurements at low temperatures (< 18 °C). The modelled temperature response indicated low fluxes at low temperatures, but measurements did not show any decrease. The irradiation response was relatively similar in both measuring sites and according to the model. Cuvette measurements showed slightly smaller quantum yields as a result from shading of the needles. The temperature dependences of the biochemical model parameters Jmax and Vc(max) were re-evaluated from the field measurements. The results for Vc(max) agreed well with earlier estimations, while the results for Jmax indicated relatively high values at low temperatures especially in northern Finland. Exponential fitting produced also substomatal concentrations of CO2, which agreed quite well with the model. The daily minimum of substomatal/ambient concentration ratio varied from 0.4 to 0.8.
  • Aalto, Department of Physics, P.O. Box 9, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: tuula.aalto@helsinki.fi (email)
article id 673, category Research article
Lauri Palva, Eero Garam, Sari Palmroth, Raimo Sepponen, Pertti Hari. (1998). Utilizing a multipoint measuring system of photosynthetically active radiation in photosynthetic studies within canopies. Silva Fennica vol. 32 no. 4 article id 673. https://doi.org/10.14214/sf.673
A novel multipoint measuring system of photosynthetically active radiation (PAR) has been constructed and operated within a Scots pine canopy. A regular grid of 800 measuring points has been incorporated into a cuvette to observe the spatial and temporal distribution of PAR incident on the needles of a twig along with simultaneous measurements of the CO2 exchange in order to determine the dependence of photosynthesis on PAR. It was shown that large errors can result if the photosynthetic rate is estimated using the mean value of PAR instead of the instantaneous values of PAR detected at given points in the region of the needles. The results demonstrate that the obtained regression between the CO2 exchange rate estimated using the multipoint PAR measuring system and the measured CO2 exchange rate is as good within a canopy as in unshaded conditions.
  • Palva, Helsinki University of Technology, Applied Electronics Laboratory, P.O. Box 3000, FIN-02015 HUT, Finland ORCID ID:E-mail: lauri.palva@hut.fi (email)
  • Garam, Helsinki University of Technology, Applied Electronics Laboratory, P.O. Box 3000, FIN-02015 HUT, Finland ORCID ID:E-mail:
  • Palmroth, University of Helsinki, Dept. of Forest Ecology, P.O. Box 24, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Sepponen, Helsinki University of Technology, Applied Electronics Laboratory, P.O. Box 3000, FIN-02015 HUT, Finland ORCID ID:E-mail:
  • Hari, University of Helsinki, Dept. of Forest Ecology, P.O. Box 24, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 682, category Research article
Guangxing Wang, Simo Poso, Mark-Leo Waite, Markus Holopainen. (1998). The use of digitized aerial photographs and local operation for classification of stand development classes. Silva Fennica vol. 32 no. 3 article id 682. https://doi.org/10.14214/sf.682
The increasing capacity of modern computers has created the opportunity to routinely process the very large data sets derived by digitizing aerial photographs. The very fine resolution of such data sets makes them better suited than satellite imagery for some applications; however, there may be problems in implementation resulting from variation in radial distortion and illumination across an aerial photograph. We investigated the feasibility of using local operators (e.g., non-overlapping moving window means and standard deviations) as auxiliary data for generating stand development classes via three steps: (i) derive 6 local operators intended to represent texture for a 16 by 16 m window corresponding to a forest inventory sampling unit, (ii) apply a calibration process (e.g., accounting for location relative to a photo's principal point and solar position) to these local operators, and (iii) apply the calibrated local operators to classify the forest for stand development. Results indicate that calibrated local operators significantly improve the classification compared to what is possible using uncalibrated local operators and satellite images.
  • Wang, Department of Natural Resources and Environmental Sciences, University of Illinois, Urbana, IL, USA ORCID ID:E-mail: wang12@staff2.cso.uiuc.edu (email)
  • Poso, Department of Forest Resource Management, P.O. Box 24, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Waite, Department of Forest Resource Management, P.O. Box 24, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Holopainen, Department of Forest Resource Management, P.O. Box 24, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 691, category Research article
Jacek Oleksyn, Mark G. Tjoelker, Peter B. Reich. (1998). Adaptation to changing environment in Scots pine populations across a latitudinal gradient. Silva Fennica vol. 32 no. 2 article id 691. https://doi.org/10.14214/sf.691
In several growth chamber and field experiments we examined the growth response of Scots pine (Pinus sylvestris L.) populations from a wide latitudinal range to temperature and photoperiod. The duration of the shoot elongation period of one-year-old seedlings was affected by temperature and photoperiod. In contrasting temperatures, 23/20 °C, 20/17 °C, and 17/14 °C (day/night), shoot elongation period for all populations was shortest in the high and longest in the low temperature treatments. The northern populations from 61–57°N ceased height growth earlier than the other populations in the southern 50°N photoperiod. The order of growth cessation among populations at 50°N in the chamber experiment and at 52°N in the field experiment was similar and related to observed population differences in terminal leader growth and total tree height. Since the length of growing season is under strong environmentally-mediated genetic control in Scots pine, potential climatic changes such as increasing temperature will probably alter the length and timing of growth in aboveground tree parts, but likely in the opposite direction (a shorter growing season) than has been often hypothesized (a longer growing season). Tree-ring analyses of a provenance experiment established in 1912 indicate that the main climatic factors that limited ring-width growth in Scots pine were air temperatures in the winter months of December through March. Low winter temperatures were followed by the formation of narrow rings over the next summer. Based on responses to temperature, Scots pine populations from the continuous European range can be divided in several geographic groups along a latitudinal gradient. Our results suggest that in developing new models to predict the response of Scots pine to changing environmental conditions, it is necessary to include intraspecific differentiation in acclimation and adaptation to environmental factors.
  • Oleksyn, Polish Academy of Sciences, Institute of Dendrology, Parkowa 5, PL-62-035 Kórnik, Poland; University of Minnesota, Department of Forest Resources, 1530 Cleveland Ave. N., St. Paul, MN 55108, USA ORCID ID:E-mail: oleks001@gold.tc.umn.edu (email)
  • Tjoelker, University of Minnesota, Department of Forest Resources, 1530 Cleveland Ave. N., St. Paul, MN 55108, USA ORCID ID:E-mail:
  • Reich, University of Minnesota, Department of Forest Resources, 1530 Cleveland Ave. N., St. Paul, MN 55108, USA ORCID ID:E-mail:
article id 689, category Research article
Erik W. Andersson, Kostas A. Spanos, Timothy J. Mullin, Dag Lindgren. (1998). Phenotypic selection compared to restricted combined index selection for many generations. Silva Fennica vol. 32 no. 2 article id 689. https://doi.org/10.14214/sf.689
A breeding population has been subjected to repeated selection and crossing by simulation. Unrestricted phenotypic selection and restricted combined index selection were compared at the same effective number for five generations. Results show that phenotypic selection often achieves the gain and diversity possible to achieve by combined index selection but the relative efficiency is different for different family sizes and heritabilities. When phenotypic selection was compared with restricted combined index method at low heritabilities, both methods performed almost equally in terms of gain at the same effective number in small family sizes, although in large families, phenotypic selection was less efficient. At high heritabilities phenotypic selection was as efficient as combined index selection. Phenotypic selection was more efficient in conserving additive variance than combined index selection over five generations compared at the same gain and effective number. The introduction of a dominance component to the total variance had little effect. An increased breeding population size by a factor of ten resulted in an increased additive gain by app. 15%. The conclusion is that even though combined index selection is superior in identifying and extracting the potential for breeding achievements, it is generally not performing better than mass selection when compared at the same effective population size in small families.
  • Andersson, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 83, Umeå, Sweden ORCID ID:E-mail: erik.andersson@genfys.slu.se (email)
  • Spanos, N.AG.RE.F.-Forest Research Institute, 57006 Vassilika, Thessaloniki, Greece ORCID ID:E-mail:
  • Mullin, Genesis Forest Science Canada Inc., C.P. 64 Succursale Haute-Ville, Québec, QC G1R 4M8 Canada ORCID ID:E-mail:
  • Lindgren, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 83, Umeå, Sweden ORCID ID:E-mail:
article id 696, category Research article
Jukka Lippu. (1998). Redistribution of 14C-labelled reserve carbon in Pinus sylvestris seedlings during shoot elongation. Silva Fennica vol. 32 no. 1 article id 696. https://doi.org/10.14214/sf.696
This study examined the later use of 14C reserves formed in previous autumn in Scots pine (Pinus sylvestris L.) seedlings. The seedlings were allowed to photosynthesise 14CO2 in early September when shoot and needle growth was over. The following spring the seedlings were harvested in five samplings during the shoot growth period. The distribution and concentration of 14C were determined and the results were compared with the growth data. It was observed that reserves were not used markedly for the new growth. Most of the 14C was found in one-year-old needles (30–40%) and in the root system (40–50%) which was due to both their high activity as a storage sink and their large sink size. The high initial 14C-activity in the finest roots decreased indicating respiration of reserves. Only a small percent of the reserve carbon was found in the new shoots which indicated that reserves are of minor importance in building a new shoot. An allocation of about 15% of the autumn storage to the stem suggested that in seedlings the stem is of minor importance as a storage organ.
  • Lippu, Department of Forest Ecology, P.O. Box 24 (Unioninkatu 40 B), FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: jukka.lippu@helsinki.fi (email)

Category: Review article

article id 249, category Review article
Rimvydas Vasaitis, Jan Stenlid, Iben M. Thomsen, Pia Barklund, Anders Dahlberg. (2008). Stump removal to control root rot in forest stands. A literature study. Silva Fennica vol. 42 no. 3 article id 249. https://doi.org/10.14214/sf.249
Tree stumps are expected to be increasingly used for energy production in Fennoscandia, thus environmental consequences of stump removal from forest land must be assessed. Aim of this work was to compile available data on the efficacy of stump removal in eradication of root rot fungi (Heterobasidion, Armillaria, and Phellinus), and to review its potential impacts on establishment and productivity of next forest generation. Site disturbance and some technical and economical aspects are discussed, and needs for future research outlined in northern European context. The review demonstrates that stump removal from clear-felled forest areas in most cases results in, a) reduction of root rot in the next forest generation, b) improved seedling establishment, and c) increased tree growth and stand productivity. Observed disturbances caused to a site by stumping operations are normally acceptable. The available data strongly suggests that possibly many (if achievable, all) rot-containing stumps must be removed during harvesting of stumps. Provided equal availability, the priority should be given for stump removal from root rot-infested forest areas, instead of healthy ones. As most studies were done in North America and Britain, several questions must be yet answered under Fennoscandian conditions: a) if and to which extent the conventional stump removal for biofuel on clear-felled sites could reduce the occurrence of Heterobasidion and Armillaria in the next forest generation, b) what impact is it likely to have on survival of replanted tree seedlings, and c) what consequences will there be for growth and productivity of next forest generation.
  • Vasaitis, Department of Forest Mycology & Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-75007 Uppsala, Sweden ORCID ID:E-mail: rimvys.vasaitis@mykopat.slu.se (email)
  • Stenlid, Department of Forest Mycology & Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-75007 Uppsala, Sweden ORCID ID:E-mail:
  • Thomsen, Forest & Landscape, University of Copenhagen, Hoersholm Kongevej 11, DK-2970 Hoersholm, Denmark ORCID ID:E-mail:
  • Barklund, Department of Forest Mycology & Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-75007 Uppsala, Sweden ORCID ID:E-mail:
  • Dahlberg, Swedish Species Information Centre, Swedish University of Agricultural Sciences, P.O. Box 7007, SE-75007 Uppsala, Sweden ORCID ID:E-mail:
article id 313, category Review article
Heikki Hänninen, Koen Kramer. (2007). A framework for modelling the annual cycle of trees in boreal and temperate regions. Silva Fennica vol. 41 no. 1 article id 313. https://doi.org/10.14214/sf.313
Models of the annual development cycle of trees in boreal and temperate regions were reviewed and classified on the basis of their ecophysiological assumptions. In our classification we discern two main categories of tree development: 1) fixed sequence development, which refers to irreversible ontogenetic development leading to visible phenological events such as bud burst or flowering, and 2) fluctuating development, which refers to reversible physiological phenomena such as the dynamics of frost hardiness during winter. As many of the physiological phenomena are partially reversible, we also describe integrated models, which include aspects of both fixed-sequence and fluctuating development. In our classification we further discern simple E-models, where the environmental response stays constant, and more comprehensive ES-models, where the environmental response changes according to the state of development. On the basis of this model classification, we have developed an operational modelling framework, in which we define an explicit state variable and a corresponding rate variable for each attribute of the annual cycle considered. We introduce a unifying notation, which we also use when presenting a selection of previously published models. To illustrate the various developmental phenomena and their modelling, we have carried out model simulations. Finally, we discuss the ecophysiological interpretation of the model variables, methodological aspects of the empirical development and testing of the models, the introduction of new aspects to the modelling, other closely related models, and applications of the models.
  • Hänninen, Plant Ecophysiology and Climate Change Group (PECC), Department of Biological and Environmental Sciences, Box 65, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: heikki.hanninen@helsinki.fi (email)
  • Kramer, Alterra, P.O. Box 47, 6700 AA Wageningen, The Netherlands ORCID ID:E-mail:
article id 313, category Review article
Heikki Hänninen, Koen Kramer. (2007). A framework for modelling the annual cycle of trees in boreal and temperate regions. Silva Fennica vol. 41 no. 1 article id 313. https://doi.org/10.14214/sf.313
Models of the annual development cycle of trees in boreal and temperate regions were reviewed and classified on the basis of their ecophysiological assumptions. In our classification we discern two main categories of tree development: 1) fixed sequence development, which refers to irreversible ontogenetic development leading to visible phenological events such as bud burst or flowering, and 2) fluctuating development, which refers to reversible physiological phenomena such as the dynamics of frost hardiness during winter. As many of the physiological phenomena are partially reversible, we also describe integrated models, which include aspects of both fixed-sequence and fluctuating development. In our classification we further discern simple E-models, where the environmental response stays constant, and more comprehensive ES-models, where the environmental response changes according to the state of development. On the basis of this model classification, we have developed an operational modelling framework, in which we define an explicit state variable and a corresponding rate variable for each attribute of the annual cycle considered. We introduce a unifying notation, which we also use when presenting a selection of previously published models. To illustrate the various developmental phenomena and their modelling, we have carried out model simulations. Finally, we discuss the ecophysiological interpretation of the model variables, methodological aspects of the empirical development and testing of the models, the introduction of new aspects to the modelling, other closely related models, and applications of the models.
  • Hänninen, Plant Ecophysiology and Climate Change Group (PECC), Department of Biological and Environmental Sciences, Box 65, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: heikki.hanninen@helsinki.fi (email)
  • Kramer, Alterra, P.O. Box 47, 6700 AA Wageningen, The Netherlands ORCID ID:E-mail:
article id 535, category Review article
Thomas J. Givnish. (2002). Adaptive significance of evergreen vs. deciduous leaves: solving the triple paradox. Silva Fennica vol. 36 no. 3 article id 535. https://doi.org/10.14214/sf.535
Patterns in the dominance of evergreen vs. deciduous plants have long interested ecologists, biogeographers, and global modellers. But previous models to account for these patterns have significant weaknesses. Bottom-up, mechanistic models – based on physiology, competition, and natural selection – have often been non-quantitative or restricted to a small range of habitats, and almost all have ignored belowground costs and whole-plant integration. Top-down, ecosystem-based models have succeeded in quantitatively reproducing several patterns, but rely partly on empirically derived constants and thresholds that lack a mechanistic explanation. It is generally recognized that seasonal drought can favor deciduous leaves, and that infertile soils can favor long-lived evergreen leaves. But no model has yet explained three great paradoxes, involving dominance by 1) evergreens in highly seasonal, boreal forests, 2) deciduous larch in many nutrient-poor peatlands, and 3) evergreen leaf-exchangers in nutrient-poor subtropical forests, even though they shed their leaves just as frequently as deciduous species. This paper outlines a generalized optimality model to account for these and other patterns in leaf longevity and phenology, based on maximizing whole-plant carbon gain or height growth, and building on recent advances in our understanding of the quantitative relationships of leaf photosynthesis, nitrogen content, and mass per unit area to leaf life-span. Only a whole-plant approach can explain evergreen dominance under realistic ecological conditions, or account for the boreal paradox, the larch paradox, the leaf-exchanger paradox, and expected shifts in shade tolerance associated with leaf phenology. Poor soils favor evergreens not merely by increasing the costs of nutrient acquisition, but also by depressing the maximum rate of photosynthesis and thus the seasonal contrast in photosynthetic return between leaves adapted to favorable vs. unfavorable conditions. The dominance of evergreens in western North America beyond the coastal zone of mild winters and winter rainfall appears related to the unusually long photosynthetic season for evergreen vs. deciduous plants there. Future models for optimal leaf phenology must incorporate differences between evergreen and deciduous plants in allocation to photosynthetic vs. non-photosynthetic tissue, rooting depth, stem allometry, xylem anatomy, and exposure to herbivores and leaching, and analyze how these differences interact with the photosynthetic rate, transpiration, and nutrient demands of leaves with different life-spans to affect rates of height growth in specific microsites.
  • Givnish, Dept of Botany, University of Wisconsin, Madison, WI 53706, USA ORCID ID:E-mail: givnish@facstaff.wisc.edu (email)
article id 693, category Review article
Erik G. Ståhl. (1998). Changes in wood and stem properties of Pinus sylvestris caused by provenance transfer. Silva Fennica vol. 32 no. 2 article id 693. https://doi.org/10.14214/sf.693
Wood properties focused in forest tree breeding should be of economic importance, have a large total variation and a high heritability. The properties of interest are those that influence the strength and durability of sawn products or the amount and properties of pulp produced. The following wood properties are treated: width of the annual ring, juvenile wood, late wood content, heart wood, tracheid dimensions, basic density, stem straightness and branch diameter. The provenance variation in wood properties can be related to differences in growth phenology. In the northern part of distribution P. sylvestris (L.) provenances transferred a few degrees southwards have a high survival and yield but stem wood production is low. Trees from these provenances will be straight and with few spike knots or other injuries. The shoot elongation period will be short and the temperature sum required for wood formation sufficient. Provenances transferred southwards will form thin annual rings, few and thin branches, little early wood, high basic density and slender tracheids with thick cell walls in comparison to local provenances. An example of the effect of alternative transfers on the yield and wood properties is evaluated. In regions with deviating climatic patterns alternative provenance transfer patterns may be better. The objectives of the land owner should influence the provenance choice. The importance of integrating tree improvement with silvicultural management is discussed with reference to spacing.
  • Ståhl, College of Dalarna, CITU Centre for Industrial Technology and Development, S-781 88 Borlänge, Sweden ORCID ID:E-mail: esl@du.se (email)

Category: Research note

article id 7771, category Research note
Māra Kitenberga, Roberts Matisons, Āris Jansons, Jānis Donis. (2018). Teleconnection between the Atlantic sea surface temperature and forest fires in Latvia and Estonia. Silva Fennica vol. 52 no. 1 article id 7771. https://doi.org/10.14214/sf.7771
Highlights: Forest fire activity in Latvia and Estonia was related to conditions in the Atlantic; Teleconnections differed regionally; Negative correlation between number of fires in Estonia and SST in the North Atlantic was detected; Area of forest fires in Estonia and activity of fires in Latvia were positively correlated with SST in the Baltic, North and Mediterranean Seas in summer.

Forest fire is one of the natural disturbances, which have important ecological and socioeconomical effect. Although fire activity is driven by weather conditions, during past two centuries forest fires have been strongly anthropogenically controlled. In this study, teleconnection between sea surface temperature (SST) in the Atlantic, which influences climate in Europe, and forest fire activity in Latvia and Estonia was assessed using “Climate explorer” web-tool. Factors affecting number and area of forest fires in Latvia and Estonia differed, suggesting regional specifics. In Estonia, the number of fires correlated with the SST in the North Atlantic in spring and summer, which affects the inflow of cool and dry air masses from the Arctic, hence the aridity and burnability. The area of fires in Estonia and in Latvia was associated with increased SST in Baltic Sea and near the European coast in summer, which likely were consequences of occurrence of warm high-pressure systems in summer, causing hot and dry conditions. Nevertheless, the observed teleconnections could be used to predict activity of forest fires in Latvia and Estonia.

  • Kitenberga, Latvian State Forest Research Institute ‘Silava’, Rigas st. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: mara.kitenberga@gmail.com (email)
  • Matisons, Latvian State Forest Research Institute ‘Silava’, Rigas st. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: robism@inbox.lv
  • Jansons, Latvian State Forest Research Institute ‘Silava’, Rigas st. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: aris.jansons@silava.lv
  • Donis, Latvian State Forest Research Institute ‘Silava’, Rigas st. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: janis.donis@silava.lv
article id 1518, category Research note
Francesco Chianucci. (2016). A note on estimating canopy cover from digital cover and hemispherical photography. Silva Fennica vol. 50 no. 1 article id 1518. https://doi.org/10.14214/sf.1518
Highlights: Comparison of fisheye (DHP) and cover (DCP) photography for estimating canopy cover; Digital photographic estimates validated against artificial images with known cover; Accuracy of cover estimates from DHP is influenced by mean gap size and actual cover; Accuracy of cover estimates from DCP is not influenced by mean gap size and actual cover.

Fast and accurate estimates of canopy cover are central for a wide range of forestry studies. As direct measurements are impractical, indirect optical methods have often been used in forestry to estimate canopy cover. In this paper the accuracy of canopy cover estimates from two widely used canopy photographic methods, hemispherical photography (DHP) and cover photography (DCP) was evaluated. Canopy cover was approximated in DHP as the complement of gap fraction data at narrow viewing zenith angle range (0°–15°), which was comparable with that of DCP. The methodology was tested using artificial images with known canopy cover; this allowed exploring the influence of actual canopy cover and mean gap size on canopy cover estimation from photography. DCP provided robust estimates of canopy cover, whose accuracy was not influenced by variation in actual canopy cover and mean gap size, based on comparison with artificial images; by contrast, the accuracy of cover estimates from DHP was influenced by both actual canopy cover and mean gap size, because of the lower ability of DHP to detect small gaps within crown. The results were replicated in both DHP and DCP images collected in real forest canopies. Finally, the influence of canopy cover on foliage clumping index and leaf area index was evaluated using a theoretical gap fraction model. The main findings indicate that DCP can overcome the limits of indirect techniques for obtaining unbiased and precise estimates of canopy cover, which are comparable to those obtainable from direct, more labour-intensive techniques, being therefore highly suitable for routine monitoring and inventory purposes.

  • Chianucci, Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria – Forestry Research Centre, viale Santa Margherita 80, 52100 Arezzo, Italy ORCID ID: http://orcid.org/0000-0002-5688-2060 E-mail: fchianucci@gmail.com (email)
article id 1518, category Research note
Francesco Chianucci. (2016). A note on estimating canopy cover from digital cover and hemispherical photography. Silva Fennica vol. 50 no. 1 article id 1518. https://doi.org/10.14214/sf.1518
Highlights: Comparison of fisheye (DHP) and cover (DCP) photography for estimating canopy cover; Digital photographic estimates validated against artificial images with known cover; Accuracy of cover estimates from DHP is influenced by mean gap size and actual cover; Accuracy of cover estimates from DCP is not influenced by mean gap size and actual cover.

Fast and accurate estimates of canopy cover are central for a wide range of forestry studies. As direct measurements are impractical, indirect optical methods have often been used in forestry to estimate canopy cover. In this paper the accuracy of canopy cover estimates from two widely used canopy photographic methods, hemispherical photography (DHP) and cover photography (DCP) was evaluated. Canopy cover was approximated in DHP as the complement of gap fraction data at narrow viewing zenith angle range (0°–15°), which was comparable with that of DCP. The methodology was tested using artificial images with known canopy cover; this allowed exploring the influence of actual canopy cover and mean gap size on canopy cover estimation from photography. DCP provided robust estimates of canopy cover, whose accuracy was not influenced by variation in actual canopy cover and mean gap size, based on comparison with artificial images; by contrast, the accuracy of cover estimates from DHP was influenced by both actual canopy cover and mean gap size, because of the lower ability of DHP to detect small gaps within crown. The results were replicated in both DHP and DCP images collected in real forest canopies. Finally, the influence of canopy cover on foliage clumping index and leaf area index was evaluated using a theoretical gap fraction model. The main findings indicate that DCP can overcome the limits of indirect techniques for obtaining unbiased and precise estimates of canopy cover, which are comparable to those obtainable from direct, more labour-intensive techniques, being therefore highly suitable for routine monitoring and inventory purposes.

  • Chianucci, Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria – Forestry Research Centre, viale Santa Margherita 80, 52100 Arezzo, Italy ORCID ID: http://orcid.org/0000-0002-5688-2060 E-mail: fchianucci@gmail.com (email)
article id 1443, category Research note
Jouni Partanen, Risto Häkkinen, Heikki Hänninen. (2016). Significance of the root connection on the dormancy release and vegetative bud burst of Norway spruce (Picea abies) seedlings in relation to accumulated chilling. Silva Fennica vol. 50 no. 1 article id 1443. https://doi.org/10.14214/sf.1443
Highlights: Cutting the root connection slightly increased the number of days to bud burst of Norway spruce seedlings under warm conditions but it had no consistent effect on bud burst percentage; Our results obtained with seedlings suggest that using detached tree material in dormancy release experiments may slightly affect the results but it will evidently not lead to drastically erroneous conclusions.

The effect of cutting the root connection by detaching the shoot from the root system on dormancy release and vegetative bud burst was examined in 2-year-old seedlings of Norway spruce (Picea abies [L.] Karst.). Seedlings were transferred at 1–4 week intervals between October and January from outdoor conditions to experimental forcing in a heated greenhouse. Before forcing, half of the seedlings were cut above ground line, and the detached shoots were forced with their cut ends placed in water. The intact seedlings were forced with their root system remaining intact in the pots. Vegetative bud burst was observed visually. Cutting the root connection slightly increased days to bud burst in the forcing conditions, however, no consistent effect on bud burst percentage was found. Our preliminary seedling data suggest that using detached tree material in dormancy release experiments may have a small effect on bud burst date but it will evidently not lead to drastically erroneous conclusions. Further studies, using different seed lots, are needed to assess the effect of detaching on the dormancy release and bud burst, especially in adult trees.

  • Partanen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: jouni.partanen@luke.fi (email)
  • Häkkinen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: risto.hakkinen@luke.fi
  • Hänninen, University of Helsinki, Department of Biosciences, Viikki Plant Science Centre (ViPS), P.O. Box 65, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: heikki.hanninen@helsinki.fi
article id 1305, category Research note
Israel Sánchez-Osorio, Luis Domínguez, Gloria López-Pantoja, Raúl Tapias. (2015). Antennal response of Prinobius myardi to synthetic tree volatiles. Silva Fennica vol. 49 no. 3 article id 1305. https://doi.org/10.14214/sf.1305
Highlights: Prinobius myardi is a wood borer considered a major threat for Mediterranean oaks, especially Quercus suber and Q. ilex; We performed electroantennographic bioassays to assess olfactory sensitivity of P. myardi to synthetic plant volatiles; P. myardi exhibits a broad sensitivity to common tree volatiles, including those emitted by oaks (α-pinene and β-pinene) or non-host volatiles (1,8-cineole).
Prinobius myardi Mulsant is a wood borer implicated in the decline of Mediterranean oaks, especially Quercus suber L. and Quercus ilex L. Plant volatiles play an important role in plant-insect interactions, and electroantennography (EAG) is an effective tool for exploring the electrophysiological activity of host plant volatiles on insects. To improve our understanding of the olfactory sensitivity of P. myardi, we recorded EAG responses to 20 tree volatiles, and analyzed the dose-dependent response to five doses (10–4:1 to 1:1 v/v) of the three most EAG-active compounds. Antennae of P. myardi responded to 13 chemicals, mainly monoterpenes and green leaf volatiles, with the strongest EAG responses being observed with β-pinene, (+)-α-pinene and 1,8-cineole. Dose–response profiles showed positive dose-dependent responses for all three compounds. Our results suggest a broad sensitivity of P. myardi to common tree volatiles, particularly some host-related compounds and volatiles associated with wounded trees; the olfactory recognition of ratios of these compounds could play a role in host selection by P. myardi.
  • Sánchez-Osorio, Departamento de Ciencias Agroforestales, ETSI La Rábida, University of Huelva, 21819 Palos de la Frontera (Huelva), Spain ORCID ID: http://orcid.org/0000-0002-6852-7699 E-mail: isanchez@uhu.es (email)
  • Domínguez, Departamento de Ciencias Agroforestales, ETSI La Rábida, University of Huelva, 21819 Palos de la Frontera (Huelva), Spain ORCID ID: http://orcid.org/0000-0002-0131-0057 E-mail: luis.dominguez@dcaf.uhu.es
  • López-Pantoja, Departamento de Ciencias Agroforestales, ETSI La Rábida, University of Huelva, 21819 Palos de la Frontera (Huelva), Spain ORCID ID: http://orcid.org/0000-0002-2659-6127 E-mail: pantoja@uhu.es
  • Tapias, Departamento de Ciencias Agroforestales, ETSI La Rábida, University of Huelva, 21819 Palos de la Frontera (Huelva), Spain ORCID ID:E-mail: rtapias@uhu.es
article id 1321, category Research note
Sofia Bäcklund, Mari T. Jönsson, Joachim Strengbom, Göran Thor. (2015). Composition of functional groups of ground vegetation differ between planted stands of non-native Pinus contorta and native Pinus sylvestris and Picea abies in northern Sweden. Silva Fennica vol. 49 no. 2 article id 1321. https://doi.org/10.14214/sf.1321
Highlights: Differences in ground vegetation patterns can be linked to tree species, forest stand age and differences in canopy cover; Vascular plant cover was higher in stands of P. contorta than in stands of both native tree species; The overall differences and similarities between P. contorta and the two native conifers were not consistent over the different age classes.
Intensified forestry increases the interest in replacing native tree species with fast growing non-native species. However, consequences for native biodiversity and ecosystem functioning are poorly understood. We compared cover and composition of major functional groups of ground vegetation between planted stands of non-native Pinus contorta Dougl. var. latifolia Engelm. and native conifers Pinus sylvestris L. and Picea abies (L.) H. Karst. in northern boreal Sweden. We quantified the ground cover of lichens, bryophytes, vascular plants and ground without vegetation (bare ground) in 96 stands covering three different age classes (15, 30 and 85 years old). Our study revealed differences in ground vegetation patterns between non-native and native managed forests, and that these differences are linked to stand age and differences in canopy cover. Total vascular plant cover increased with increasing stand age for all tree species, with P. contorta stands having higher cover than both native conifers. The ground cover of lichens was, although generally low, highest in stands of Pinus sylvestris. P. abies stands had a lower cover of vascular plants, but bare ground was more common compared with P. contorta. Our results suggest that the use of P. contorta as an alternative tree species in Fennoscandian forestry will influence native ground vegetation patterns. This influence is likely to change with time and future research should consider both temporal and landscape-scale effects from shifting tree-species dominance to Pinus contorta and other non-native tree species.
  • Bäcklund, Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: sofia.backlund@slu.se (email)
  • Jönsson,  The Swedish Species Information Centre, P.O. Box 7007, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: mari.jonsson@slu.se
  • Strengbom, Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: joachim.strengbom@slu.se
  • Thor, Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: goran.thor@slu.se
article id 1145, category Research note
Juha Siitonen. (2014). Ips acuminatus kills pines in southern Finland. Silva Fennica vol. 48 no. 4 article id 1145. https://doi.org/10.14214/sf.1145
Highlights: Recently dead pines colonized by Ips acuminatus were frequently found in southern Finland, in a region where the species was thought to be absent; Colonized trees were typically large (average DBH 30 cm), located at open spots in pine-dominated stands, often forming groups of several trees; The damages may be a consequence of dry and hot summers during the 2000s.
Recently dead Scots pines (Pinus sylvestris L.) apparently killed by Ips acuminatus (Gyllenhal) were observed in Sipoo, southern Finland, in summer 2013. This record was unexpected and in contradiction with what is currently known about the distribution and aggressiveness of the species in Finland. The aim of this study was to survey a larger area in Uusimaa region, to find out whether I. acuminatus occurs frequently in recently dead pines, and whether inhabited trees share some common tree- or site-level characteristics. Galleries of I. acuminatus were found in most of the studied trees. A total of 96 inhabited trees were found in 21 separate sites. Colonized pines were typically large (average DBH 30 ± 9 cm) trees located in relatively open pine-dominated heathland stands at half-open, sun-exposed spots. The whole upper part of the trunk with thin bark was usually occupied. Galleries of Tomicus piniperda L. or T. minor Hartig occurred only in few cases in the same trees, indicating that the trees had died later in the summer. Galleries of the jewel beetle Phaenops cyanea F. were found in 13 trees. Trees colonized by I. acuminatus often occurred as small groups, with generally 1­–12 trees (average 3 trees), but in one exceptional group there were no less than 35 trees. It is possible that the hot and dry summers during the 2000s have increased the susceptibility of pines to insect damage, and have contributed to a population growth of I. acuminatus.
  • Siitonen, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: juha.siitonen@metla.fi (email)
article id 268, category Research note
Adam Boratynski, Katarzyna Marcysiak, Amelia Lewandowska, Anna Jasinska, Grzegorz Iszkulo, Jaroslaw Burczyk. (2008). Differences in leaf morphology between Quercus petraea and Q. robur adult and young individuals. Silva Fennica vol. 42 no. 1 article id 268. https://doi.org/10.14214/sf.268
The characters of Quercus robur and Q. petraea leaves are of main taxonomic value and the adult trees of both species can be distinguished on them. However, young individuals, mostly seedlings but also saplings, are told to be undistinguishable or only partly distinguishable on the leaf morphology. The aim of the study was to verify this hypothesis on the basis of biometrical analyses of leaf characteristics of adults trees and saplings in two mixed oak woods, one located close to the north-eastern limit, the other about 400 km inside of the Q. petraea range in Poland. The analysis of discriminations and minimum spanning tree on the squares of Mahalanobis distances were analysed to find differences between Q. robur, Q. petraea and intermediate adults and saplings. The differences between saplings of Q. robur and Q. petraea were found lower than between adult trees. Nevertheless, the biometrical analysis confirmed determination of saplings in the field.
  • Boratynski, Polish Academy of Sciences, Institute of Dendrology, 5 Parkowa str., 62-035 Kórnik, Poland ORCID ID:E-mail: borata@man.poznan.pl (email)
  • Marcysiak, Kazimierz Wielki University, Institute of Biology and Environment Protection, 12 Ossolinskich str., 85-064 Bydgoszcz, Poland ORCID ID:E-mail:
  • Lewandowska, Kazimierz Wielki University, Institute of Biology and Environment Protection, 12 Ossolinskich str., 85-064 Bydgoszcz, Poland ORCID ID:E-mail:
  • Jasinska, Polish Academy of Sciences, Institute of Dendrology, 5 Parkowa str., 62-035 Kórnik, Poland ORCID ID:E-mail:
  • Iszkulo, Polish Academy of Sciences, Institute of Dendrology, 5 Parkowa str., 62-035 Kórnik, Poland ORCID ID:E-mail:
  • Burczyk, Kazimierz Wielki University, Institute of Biology and Environment Protection, 12 Ossolinskich str., 85-064 Bydgoszcz, Poland ORCID ID:E-mail:
article id 268, category Research note
Adam Boratynski, Katarzyna Marcysiak, Amelia Lewandowska, Anna Jasinska, Grzegorz Iszkulo, Jaroslaw Burczyk. (2008). Differences in leaf morphology between Quercus petraea and Q. robur adult and young individuals. Silva Fennica vol. 42 no. 1 article id 268. https://doi.org/10.14214/sf.268
The characters of Quercus robur and Q. petraea leaves are of main taxonomic value and the adult trees of both species can be distinguished on them. However, young individuals, mostly seedlings but also saplings, are told to be undistinguishable or only partly distinguishable on the leaf morphology. The aim of the study was to verify this hypothesis on the basis of biometrical analyses of leaf characteristics of adults trees and saplings in two mixed oak woods, one located close to the north-eastern limit, the other about 400 km inside of the Q. petraea range in Poland. The analysis of discriminations and minimum spanning tree on the squares of Mahalanobis distances were analysed to find differences between Q. robur, Q. petraea and intermediate adults and saplings. The differences between saplings of Q. robur and Q. petraea were found lower than between adult trees. Nevertheless, the biometrical analysis confirmed determination of saplings in the field.
  • Boratynski, Polish Academy of Sciences, Institute of Dendrology, 5 Parkowa str., 62-035 Kórnik, Poland ORCID ID:E-mail: borata@man.poznan.pl (email)
  • Marcysiak, Kazimierz Wielki University, Institute of Biology and Environment Protection, 12 Ossolinskich str., 85-064 Bydgoszcz, Poland ORCID ID:E-mail:
  • Lewandowska, Kazimierz Wielki University, Institute of Biology and Environment Protection, 12 Ossolinskich str., 85-064 Bydgoszcz, Poland ORCID ID:E-mail:
  • Jasinska, Polish Academy of Sciences, Institute of Dendrology, 5 Parkowa str., 62-035 Kórnik, Poland ORCID ID:E-mail:
  • Iszkulo, Polish Academy of Sciences, Institute of Dendrology, 5 Parkowa str., 62-035 Kórnik, Poland ORCID ID:E-mail:
  • Burczyk, Kazimierz Wielki University, Institute of Biology and Environment Protection, 12 Ossolinskich str., 85-064 Bydgoszcz, Poland ORCID ID:E-mail:
article id 534, category Research note
Ilkka Leinonen, Heikki Hänninen. (2002). Adaptation of the timing of bud burst of Norway spruce to temperate and boreal climates. Silva Fennica vol. 36 no. 3 article id 534. https://doi.org/10.14214/sf.534
The adaptation of the annual cycle of development of boreal and temperate trees to climatic conditions has been seen as a result of stabilizing selection caused by two opposite driving forces of natural selection, i.e. the tolerance of unfavorable conditions during the frost exposed season (survival adaptation) and the effective use of growth resources during the growing season (capacity adaptation). In this study, two theories of the effects of climate on the adaptation of the timing of bud burst of trees were evaluated. This was done with computer simulations by applying a temperature sum model for predicting the timing of bud burst of different Norway spruce genotypes on the basis of air temperature data from various climatic conditions. High geographical variation in the temperature response of bud burst, typical for Norway spruce, was included in the theoretical analyses. The average timing of bud burst and the corresponding risk of occurrence of damaging frost during the susceptible period after bud burst were calculated for each genotype in each climate. Two contrasting theories of the stabilizing selection were evaluated, i.e. the overall adaptedness of each genotype was evaluated either 1) by assuming a fixed threshold for the risk of frost damage, or 2) by assuming a tradeoff between the risk of frost damage and the length of the growing season. The tradeoff assumption produced predictions of between provenance variation in bud burst which correspond more closely with empirical observations available in literature, compared to the fixed threshold assumption.
  • Leinonen, University of Oklahoma, Department of Botany and Microbiology, Norman, OK 73019, USA ORCID ID:E-mail: leinonen@ou.edu (email)
  • Hänninen, University of Helsinki, Department of Ecology and Systematics, FIN-00014 Helsinki, Finland ORCID ID:E-mail:
article id 608, category Research note
Jouni Partanen, Ilkka Leinonen, Tapani Repo. (2001). Effect of accumulated duration of the light period on bud burst in Norway spruce (Picea abies) of varying ages. Silva Fennica vol. 35 no. 1 article id 608. https://doi.org/10.14214/sf.608
One-year-old seedlings (two sowing times), two-year-old seedlings and 14- and 18-year-old cuttings of Norway spruce (Picea abies (L.) Karst.) were exposed to shortening photoperiod (initially 16 h), lengthening photoperiod (initially 6 h) and constant short photoperiod (6 h) treatments with uniform temperature conditions in growth chambers. The timing of bud burst was examined. In all plants, shortening photoperiod treatment seemed to promote bud burst compared with other treatments. This effect was clearest in the oldest material. The results suggest that, in addition to temperature sum, the accumulated duration of the light period may promote bud burst of Norway spruce.
  • Partanen, Finnish Forest Research Institute, Punkaharju Research Station, Finlandiantie 18, FIN-58450 Punkaharju, Finland ORCID ID:E-mail: jouni.partanen@metla.fi (email)
  • Leinonen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Repo, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
article id 608, category Research note
Jouni Partanen, Ilkka Leinonen, Tapani Repo. (2001). Effect of accumulated duration of the light period on bud burst in Norway spruce (Picea abies) of varying ages. Silva Fennica vol. 35 no. 1 article id 608. https://doi.org/10.14214/sf.608
One-year-old seedlings (two sowing times), two-year-old seedlings and 14- and 18-year-old cuttings of Norway spruce (Picea abies (L.) Karst.) were exposed to shortening photoperiod (initially 16 h), lengthening photoperiod (initially 6 h) and constant short photoperiod (6 h) treatments with uniform temperature conditions in growth chambers. The timing of bud burst was examined. In all plants, shortening photoperiod treatment seemed to promote bud burst compared with other treatments. This effect was clearest in the oldest material. The results suggest that, in addition to temperature sum, the accumulated duration of the light period may promote bud burst of Norway spruce.
  • Partanen, Finnish Forest Research Institute, Punkaharju Research Station, Finlandiantie 18, FIN-58450 Punkaharju, Finland ORCID ID:E-mail: jouni.partanen@metla.fi (email)
  • Leinonen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Repo, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:

Category: Article

article id 7181, category Article
Eino Oinonen. (1967). Keltalieon (Lycopodium complanatum L.) itiöllinen uudistuminen Etelä-Suomessa kloonien laajuutta ja ikää koskevan tutkimuksen valossa. Acta Forestalia Fennica vol. 83 no. 3 article id 7181. https://doi.org/10.14214/aff.7181
English title: Sporal regeneration of ground pine (Lycopodium complanatum L.) in Southern Finland in the light of the dimensions and the age of its clones.

In an earlier paper of the author it was established that sporal regeneration of bracken fern (Pteridium aquilinum (L.) Kuhn.) is almost entirely connected with fire, and that the size of the bracken fern clones, distinguished by their characteristics, was related to the time of the fire. In previous studies has been found that also sporal regeneration of ground pine (Lycopodium complanatum L., now Diphasiastrum complanatum) is rare. The occurrence of several plant species were studied in relation to bracken fern in the earlier investigation. This paper reports findings concerning ground pine.

When the size-age problem of bracken fern was solved, parallel measurements of ground pine stand on the same site led to the solution of the size-age problem and sporal regeneration of ground pine. The linkage is also valid when the size of ground pine stands was compared to the dates of fires. The ground pine stands are very long-lasting. The stands are fragmented more easily than bracken fern by environmental factors, such as fires, and tend to form large patch clusters with time. Large individual stands reveal the rarity of sporal regeneration of ground pine. The resemblance with bracken fern clones indicate a common factor of regeneration, fire, and a very even spreading rate. Though considerable variation of the colour and structure of ground pine was observed, the circular stands were identical patch by patch.

The PDF includes a summary in English.

  • Oinonen, ORCID ID:E-mail:
article id 7177, category Article
Aarne Nyyssönen, Simo Poso, Christian Keil. (1968). The use of aerial photographs in the estimation of some forest characteristics. Acta Forestalia Fennica vol. 82 no. 4 article id 7177. https://doi.org/10.14214/aff.7177

The aim of this investigation is to study, for north European conditions, some overall standards of accuracy attainable in the estimation in a number of forest characteristics from aerial photographs. Field data was acquired in three areas, comprising whole stands, fixed and variable size sample plots and sections of survey strips.  

The results show that land use classes could be estimated to a rather high degree of precision from aerial photographs. The accuracy of determination of the main tree species (Scots pine, Norway spruce and deciduous trees) was more moderate; three quarters of all stands were interpreted correctly from the present photographs. The estimate of pure stands was noticeable better than those for mixed stands. In general, the agreement between treatment class stratification in the field and from aerial photographs was poor, as only one-third of all cases the class was same. The dominant height was estimated with relative lack of bias for small stands, but systematic underestimation of nearly 2 m existed for high stands.  

The emphasis in this investigation was laid on determination of the volume of growing stock. Stand volumes in the small and medium volume classes were overestimated, against clear under-estimate for high volume stands. The standard error of difference, including bias, was ±43 both in m3 and as a percentage. 

The variance data available provide a basis for the conclusion that under some conditions photo stratification within the forest land seems to improve the efficiency of volume estimation, whereas in some other cases the stratification is hardly an economic proposition. Alternative computations made from the data of an experimental survey indicated the likelihood that no gain was deprived from the use of aerial photographs for volume class estimation. 

The PDF includes a summary in Finnish.

  • Nyyssönen, ORCID ID:E-mail:
  • Poso, ORCID ID:E-mail:
  • Keil, ORCID ID:E-mail:
article id 7416, category Article
Erkki Laitakari. (1954). Nuori Hannikainen metsäpoliitikkona. Acta Forestalia Fennica vol. 61 no. 4 article id 7416. https://doi.org/10.14214/aff.7416
English title: The young Hannikainen as a forest politician.
English keywords: biography; forestry

The article revises the accomplishments of professor Peter Woldemar Hannikainen, the former director of Forest Service of Finland, in the development of forest sector in the end of 1800s and beginning of 1900s.

The PDF includes a summary in German.

  • Laitakari, ORCID ID:E-mail:
article id 7406, category Article
Jaakko O. Murto. (1951). Mäntypuumme pihka voiteluöljyn raaka-aineena : puunkäyttöopillinen tutkimus. Acta Forestalia Fennica vol. 59 no. 2 article id 7406. https://doi.org/10.14214/aff.7406
English title: Finnish Scots pine resin as raw material for lubricating oil.

After the Second World War shortage of lubrication oil forced Finland to develop a substitute product that was produced of indigenous materials. This report is an overview of the history of the already terminated lubricating oil industry and it gives a detailed description of lubricating oil production.

The annual lubricating oil consumption in Finland was 15,000 tons before the war, but during the war it decreased to 7-8,000 tons. In 1943 Oy Tervaöljy Ab (Tar Oil Limited) was established with the state of Finland as the main shareholder. It was commissioned to plan and build tar and tar oil plants, and it also transmitted tar from stump wood pyrolyzing plants to oil factories. Two raw materials were used to produce tar oil: tar wood collected from Scots pine (Pinus sylvestris L.) stumps and tall oil, a by-product of sulphate pulp mills. A total of 9,000 tons of lubricating oil substitutes was produced in 1943-1947, 53% of this from sulphate pulp mill by-products and 47% from tar and shale oil.

The PDF includes a summary in English.

  • Murto, ORCID ID:E-mail:
article id 7362, category Article
Olavi Linnamies. (1942). Metsätalouskartaston soveltaminen sotilastarkoituksiin. Acta Forestalia Fennica vol. 50 no. 9 article id 7362. https://doi.org/10.14214/aff.7362
English title: Use of forest maps in military purposes in Finland.

The Second World War revealed some weaknesses that affect also peacetime planning of military defence in Finland. One of the shortages were lack of maps applicable in military purposes in Northern Finland.

The state forests are mainly situated in the north. Consequently, cartographic material of Finnish Forest Service may be modified with little extra work for military purposes. Best suited for the purpose are forestry maps of different forest districts that have scales ranging from 1:20,000 to 1:100,000. In addition, general maps in the scale of 1:100,000 or 1:200,000 are available. The article discusses further the additions that can be made in the maps.

The PDF includes a summary in German.

  • Linnamies, ORCID ID:E-mail:
article id 7360, category Article
Viljo Kujala. (1942). Über die morphologische Deutung des Fichtenzapfens auf Grund eines Fertilisationsfalles. Acta Forestalia Fennica vol. 50 no. 7 article id 7360. https://doi.org/10.14214/aff.7360
English title: Morphologic interpretation of a spruce cone based on fertilization.
Original keywords: Fichte; Zapf; Fertilisation; Morfologie
English keywords: spruce; cone; fertilization; morphology

Article presents some rare cone formations found from a small spruce in region of Punkaharju, Finland. In this case all the scales have developed into perfect, green needle leaves. Instead of a normal scale of a cone there are formations of buds that on the basal part of a cone resemble a normal bud, and hence develop into a branch. On the upper part of the cone formation the bud develops into scale of a cone.

The morphological form of the cones has been interpreted many ways. These anomalies resemble earlier observations and hence support the former theory of inflorescence. According the theory, the scales and scales of a cone are separate leaves, the scale corresponding to one leaf, the scale of a cone corresponding to two leaves. A cone is hence rather to be compared with a branching inflorescence than only one flower.

The PDF contains a summary in Finnish. 

  • Kujala, ORCID ID:E-mail:
article id 7350, category Article
Ilmari Paasio. (1941). Zur Pflanzensoziologischen Grundlage der Weissmoortypen. Acta Forestalia Fennica vol. 49 no. 3 article id 7350. https://doi.org/10.14214/aff.7350
English title: Plant sociological principles of open bog types.

The plant populations of Finnish open bogs are typically formed of two layers. The layers normally consist of one or rarely two species. The structure of plant populations in open bogs is a consequence of the development where determining factors are different site requirements of the species, and the differences in the biotic vitality and capacity for reproduction.

Phytogenesis should be taken as a basic unit for describing the plant societies or vegetation of treeless bogs. However, acknowledging the sub-populations may be of advantage for describing the ecological, genetic and regional characters of open bogs.

The basic classification of open bogs must be done based on the ground layer. The more detailed classification follows mostly based on field layer, partly also based on the ground layer.

The PDF contains a summary in Finnish. 

  • Paasio, ORCID ID:E-mail:
article id 7350, category Article
Ilmari Paasio. (1941). Zur Pflanzensoziologischen Grundlage der Weissmoortypen. Acta Forestalia Fennica vol. 49 no. 3 article id 7350. https://doi.org/10.14214/aff.7350
English title: Plant sociological principles of open bog types.

The plant populations of Finnish open bogs are typically formed of two layers. The layers normally consist of one or rarely two species. The structure of plant populations in open bogs is a consequence of the development where determining factors are different site requirements of the species, and the differences in the biotic vitality and capacity for reproduction.

Phytogenesis should be taken as a basic unit for describing the plant societies or vegetation of treeless bogs. However, acknowledging the sub-populations may be of advantage for describing the ecological, genetic and regional characters of open bogs.

The basic classification of open bogs must be done based on the ground layer. The more detailed classification follows mostly based on field layer, partly also based on the ground layer.

The PDF contains a summary in Finnish. 

  • Paasio, ORCID ID:E-mail:
article id 7320, category Article
J. J. Carlberg. (1935). Bestämning av pH-värdet i utspädda bikarbonatlösningar vid olika CO2-tryck. Acta Forestalia Fennica vol. 42 no. 3 article id 7320. https://doi.org/10.14214/aff.7320
English title: Analysis of pH in diluted bicarbonate solutions using different partial pressures of CO2.

The paper is a dissertation paper that describes analysis of pH in diluted bicarbonate solutions using different partial pressures of CO2. In the work, an equation was obtained from the balance equations of a base-bicarbonate-water system. Similarly, an equation was obtained to describe the relationship of partial pressure of CO2 and hydrogen ion concentration of a bicarbonate solution. This equation can be used to determine the bicarbonate concentration of a gas mixture.

The PDF includes a Finnish and German summary.

  • Carlberg, ORCID ID:E-mail:
article id 7284, category Article
K. Linkola. (1934). Die Flatterulme (Ulmus laevis Pall.) in der Gegend des Vanajavesisees. Acta Forestalia Fennica vol. 40 no. 7 article id 7284. https://doi.org/10.14214/aff.7284
English title: European white elm (Ulmus laevis Pall.) in the region of Vanajavesi-lake.

The article describes the distribution of the European white elm; its sites and vegetation communes; phenotype (size and form); variations in the leaves; inflorescence and fruiting; germinative capacity of the seeds; regeneration, both vegetative propagation and from seeds; commercial use of the timber; and the history of European white elm.

The PDF contains a summary in Finnish.  

  • Linkola, ORCID ID:E-mail:
article id 7227, category Article
D. Fehér. (1929). Die Biologie des Waldbodens und ihre physiologische Bedeutung im Leben des Waldes. Acta Forestalia Fennica vol. 34 no. 14 article id 7227. https://doi.org/10.14214/aff.7227
English title: Biology of forest soil and its physiological meaning in the life of forest.

The article presents three studies about different aspects of the bio-chemical functions of forest soil. The three studies are i) research on microflora and microfauna of forest soils; ii) study on carbon nutrition of forests in relation to microbial functions of soil and effecting site factors and iii) study on nitrogen metabolism of forest soil. The results of the studies are summarized by every study.

The article discusses the meaning of the results for forest management in practice. The good biological and physiological condition of forest soil is important for the forest growth and it needs to be taken care in regeneration and other forest management. The natural regeneration seems to be better for soil functions. Favoring broadleaved trees as undergrowth enhances the biological processes of forest soil.   

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander.

  • Fehér, ORCID ID:E-mail:
article id 7227, category Article
D. Fehér. (1929). Die Biologie des Waldbodens und ihre physiologische Bedeutung im Leben des Waldes. Acta Forestalia Fennica vol. 34 no. 14 article id 7227. https://doi.org/10.14214/aff.7227
English title: Biology of forest soil and its physiological meaning in the life of forest.

The article presents three studies about different aspects of the bio-chemical functions of forest soil. The three studies are i) research on microflora and microfauna of forest soils; ii) study on carbon nutrition of forests in relation to microbial functions of soil and effecting site factors and iii) study on nitrogen metabolism of forest soil. The results of the studies are summarized by every study.

The article discusses the meaning of the results for forest management in practice. The good biological and physiological condition of forest soil is important for the forest growth and it needs to be taken care in regeneration and other forest management. The natural regeneration seems to be better for soil functions. Favoring broadleaved trees as undergrowth enhances the biological processes of forest soil.   

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander.

  • Fehér, ORCID ID:E-mail:
article id 7216, category Article
L. Cockayne. (1929). Hybridism in the forests of New Zealand. Acta Forestalia Fennica vol. 34 no. 3 article id 7216. https://doi.org/10.14214/aff.7216

The article gives examples of hybridization of forest tree and shrub species in the forests of New Zealand. According to the article, many of the 498 vascular plant species in the forest communities of the New Zealand region must be excluded from the standpoint of hybridism, because they belong either to genera of one species or are unable to cross owing to geographical or biological isolation. The hybrids are in most cases jordanons which cross, and may be more or less distantly related or closely related. The hybrids occur usually in polymorphic groups. Most of the hybrids in New Zealand are fertile. The hybrids can affect the forest communities in two ways; by effecting their composition or their structure. The article includes a list of hybrid groups.

Jubileum publication of professor Aimo Kaarlo Cajander.

  • Cockayne, ORCID ID:E-mail:
article id 5638, category Article
Markku Tykkyläinen, Pentti Hyttinen, Ari Mononen. (1997). Theories of regional development and their relevance to the forest sector. Silva Fennica vol. 31 no. 4 article id 5638. https://doi.org/10.14214/sf.a8540

The paper elaborates upon various theories to explain economic development and restructuring in the forested regions of advanced countries. The concepts of communities based on the forest sector and the concept of restructuring are discussed before presenting the diversity of relevant theories. Different theoretical approaches in geography and regional and socio-economic sciences are analysed, and the paper concludes that each theory gives only a partial explanation of restructuring under certain conditions. This paper recommends that an explanatory framework should take into account – in addition to general explanatory factors – sectoral, local-specific and policy-related factors and the role of human agency in attempts to explain restructuring and development.

  • Tykkyläinen, ORCID ID:E-mail:
  • Hyttinen, ORCID ID:E-mail:
  • Mononen, ORCID ID:E-mail:
article id 5637, category Article
Janne Uuttera, Harri Hyppänen. (1997). Relationship between forest management planning units and spatial distribution of forest habitat components in Koli National Park. Silva Fennica vol. 31 no. 4 article id 5637. https://doi.org/10.14214/sf.a8539

This study examined the relationships between forest management planning units and patches formed by forest habitat components. The test area used was a part of Koli National Park in North Karelia, eastern Finland. Forest management planning units (i.e. forest compartments) were defined by using a traditional method of Finnish forestry which applies aerial photographs and compartment-wise field inventory. Patches of forest habitat components were divided according to subjective rules by using a chosen set of variables depicting the edaphic features and vegetation of a forest habitat. The spatial distribution of the habitat components was estimated with the kriging-interpolation based on systematically located sample plots. The comparisons of the two patch mosaics were made by using the standard tools of GIS. The results of the study show that forest compartment division does not correlate very strongly with the forest habitat pattern. On average, the mean patch size of the forest habitat components is greater and the number of these patches lower compared to forest compartment division. However, if the forest habitat component distribution had been considered, the number of the forest compartments would have at least doubled after intersection.

  • Uuttera, ORCID ID:E-mail:
  • Hyppänen, ORCID ID:E-mail:
article id 5627, category Article
Philippe de Reffye, Daniel Barthélémy, Frédéric Blaise, Thierry Fourcaud, François Houllier. (1997). A functional model of tree growth and tree architecture. Silva Fennica vol. 31 no. 3 article id 5627. https://doi.org/10.14214/sf.a8529

A new approach for modelling plant growth using the software AMAPpara is presented. This software takes into consideration knowledge about plant architecture which has been accumulated at the Plant Modelling Unit of CIRAD for several years, and introduces physiological concepts in order to simulate the dynamic functioning of trees. The plant is considered as a serial connection of vegetative organs which conduct water from the roots to the leaves. Another simple description of the plant as a network of parallel pipes is also presented which allows an analytical formulation of growth to be written. This recurring formula is used for very simple architectures and is useful to understand the role of each organ in water transport and assimilate production. Growth simulations are presented which show the influence of modifications in architecture on plant development.

  • de Reffye, ORCID ID:E-mail:
  • Barthélémy, ORCID ID:E-mail:
  • Blaise, ORCID ID:E-mail:
  • Fourcaud, ORCID ID:E-mail:
  • Houllier, ORCID ID:E-mail:
article id 5626, category Article
Winfried Kurth, Branislav Sloboda. (1997). Growth grammars simulating trees – an extension of L-systems incorporating local variables and sensitivity. Silva Fennica vol. 31 no. 3 article id 5626. https://doi.org/10.14214/sf.a8527

The rule-based formal language of "stochastic sensitive growth grammars" was designed to describe algorithmically the changing morphology of forest trees during their lifetime under the impact of endogenous and exogenous factors, and to generate 3-D simulations of tree structures in a systematic manner. The description in the form of grammars allows the precise specification of structural models with functional components. These grammars (extended L-systems) can be interpreted by the software GROGRA (Growth grammar interpreter) yielding time series of attributed 3-D structures representing plants. With some recent extensions of the growth-grammar language (sensitive functions, local variables) it is possible to model environmental control of shoot growth and some simple allocation strategies, and to obtain typical competition effects in tree stands qualitatively in the model.

  • Kurth, ORCID ID:E-mail:
  • Sloboda, ORCID ID:E-mail:
article id 5624, category Article
Hervé Sinoquet, Christophe Godin, Pierre Rivet. (1997). Assessment of the three-dimensional architecture of walnut trees using digitising. Silva Fennica vol. 31 no. 3 article id 5624. https://doi.org/10.14214/sf.a8525

A method for the measurement of the three-dimensional (3D) architecture of trees was applied to describe two 20-year-old walnut trees, one of them is a timber tree while the other is a fruit tree. The method works at the shoot level and simultaneously describes the plant topology, the plant geometry and the shoot morphology. The method uses a 3D digitiser (3SPACE® FASTRAK®, Polhemus Inc.) associated with software DiplAmi designed for digitiser control and data acquisition management. Plant images may be reconstructed from the data set by using the ray tracing software POV-Ray. Visual comparison between photographs of the walnut trees and images synthesised from digitising was satisfactory. Distribution of basal shoot diameter, as well as leaf area and fruit distributions for both the timber and the fruit tree were non-uniformly distributed in the crown volume. Gradients were likely to be related to the light distribution within the tree. This is in agreement with previous experimental results on several tree species, and also with the predictions of tree architecture models based on light-vegetation interactions.

  • Sinoquet, ORCID ID:E-mail:
  • Godin, ORCID ID:E-mail:
  • Rivet, ORCID ID:E-mail:
article id 5618, category Article
Marja-Leena Nykänen, Marianne Broadgate, Seppo Kellomäki, Heli Peltola, Christopher Quine. (1997). Factors affecting snow damage of trees with particular reference to European conditions. Silva Fennica vol. 31 no. 2 article id 5618. https://doi.org/10.14214/sf.a8519

Within the European Community snow damage affects an estimated 4 million m3 of timber every year, causing significant economic losses to forest owners. In Northern Europe, for example, the occurrence of snow damage has increased over the last few decades mainly due to the increase in total growing stock. The most common form of damage is stem breakage, but trees can also be bent or uprooted. Trees suffering snow damage are also more prone to consequential damage through insect or fungal attacks.

Snow accumulation on trees is strongly dependent upon weather and climatological conditions. Temperature influences the moisture content of snow and therefore the degree to which it can accumulate on branches. Wind can cause snow to be shed, but can also lead to large accumulations of wet snow, rime or freezing rain. Wet snow is most likely in late autumn or early spring. Geographic location and topography influence the occurrence of damaging forms of snow, and coastal locations and moderate to high elevations experience large accumulations. Slope plays a less important role and the evidence on the role of aspect is contradictory. The occurrence of damaging events can vary from every winter to once every 10 years or so depending upon regional climatology. In the future, assuming global warming in northern latitudes, the risk of snow damage could increase, because the relative occurrence of snowfall near temperatures of zero could increase.

The severity of snow damage is related to tree characteristics. Stem taper and crown characteristics are the most important factors controlling the stability of trees. Slightly tapering stems, asymmetric crowns, and rigid horizontal branching are all associated with high risk. However, the evidence on species differences is less clear due to the interaction with location. Management of forests can alter risk through choice of regeneration, tending, thinning and rotation. However, quantification and comparison of the absolute effect of these measures is not yet possible. An integrated risk model is required to allow the various locational and silvicultural factors to be assessed. Plans are presented to construct such a model, and gaps in knowledge are highlighted.

  • Nykänen, ORCID ID:E-mail:
  • Broadgate, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
  • Peltola, ORCID ID:E-mail:
  • Quine, ORCID ID:E-mail:
article id 5617, category Article
Teijo Palander. (1997). A local DLP-GIS-LP system for geographically decentralized wood procurement planning and decision making. Silva Fennica vol. 31 no. 2 article id 5617. https://doi.org/10.14214/sf.a8518

Linear programming (LP) is an important method for allocation of wood inventory stock. It is, for instance, used alone in tactical planning systems, which currently are in wide use at the higher hierarchical level in the functionally decentralized planning of the Finnish forest industry. Unfortunately, LP as a solution method has not been capable of handling spatial data that seem to characterize planning systems in geographical decentralization. In the present study, GIS was used to assimilate data from different wood procurement functions, to calculate transportation distances and cost figures, and to write the data in ASCII files, which were then used as input for the LP model. Using the experiments and methods of GIS on a planning system developed according to participatory planning, the results of this study suggest that the participatory method was faster than the conventional LP method, when solved using actual data. The participatory method was also capable of providing the same global optimum for a wood allocation problem. The implications of these results for improving operational and tactical planning of wood procurement in Finland are discussed.

  • Palander, ORCID ID:E-mail:
article id 5611, category Article
Arja Lilja, Timo Kurkela, Sakari Lilja, Risto Rikala.. (1997). Nursery practices and management of fungal diseases in forest nurseries in Finland. A review. Silva Fennica vol. 31 no. 1 article id 5611. https://doi.org/10.14214/sf.a8512

The purpose of this article was to collate the literature on fungal diseases that occur on seedlings in forest nurseries. It describes the symptoms of the diseases, the infection pattern of each fungus and the possibilities of controlling the diseases. As background a short introduction is given on forests and nursery practices in Finland.

  • Lilja, ORCID ID:E-mail:
  • Kurkela, ORCID ID:E-mail:
  • Lilja, ORCID ID:E-mail:
  • Rikala., ORCID ID:E-mail:
article id 5611, category Article
Arja Lilja, Timo Kurkela, Sakari Lilja, Risto Rikala.. (1997). Nursery practices and management of fungal diseases in forest nurseries in Finland. A review. Silva Fennica vol. 31 no. 1 article id 5611. https://doi.org/10.14214/sf.a8512

The purpose of this article was to collate the literature on fungal diseases that occur on seedlings in forest nurseries. It describes the symptoms of the diseases, the infection pattern of each fungus and the possibilities of controlling the diseases. As background a short introduction is given on forests and nursery practices in Finland.

  • Lilja, ORCID ID:E-mail:
  • Kurkela, ORCID ID:E-mail:
  • Lilja, ORCID ID:E-mail:
  • Rikala., ORCID ID:E-mail:
article id 5570, category Article
Anne Toppinen, Riitta Hänninen, Susanna Laaksonen. (1996). A dynamic forecasting model for the Finnish pulp export price. Silva Fennica vol. 30 no. 4 article id 5570. https://doi.org/10.14214/sf.a8505

This study investigates the relationship between Finnish sulphate pulp export prices and international pulp inventories using the Johansen cointegration method. Long-run equilibrium is found to exist between pulp price and NORSCAN inventory for the study period, 1980-94. Granger causality is found to exist from inventory to price but not vice versa. A simple short-run forecasting model for the Finnish pulp export price is formed. In preliminary analysis, the explanatory power of model is found to be acceptable but only under stable market conditions.

  • Toppinen, ORCID ID:E-mail:
  • Hänninen, ORCID ID:E-mail:
  • Laaksonen, ORCID ID:E-mail:
article id 5595, category Article
R.A. Fleming. (1996). A mechanistic perspective of possible influences of climate change on defoliating insects in North America's boreal forests. Silva Fennica vol. 30 no. 2–3 article id 5595. https://doi.org/10.14214/sf.a9240

There is no doubt that tree survival, growth, and reproduction in North America's boreal forests would be directly influenced by the projected changes in climate if they occur. The indirect effects of climate change may be of even greater importance, however, because of their potential for altering the intensity, frequency, and perhaps even the very nature of the disturbance regimes which drive boreal forest dynamics. Insect defoliator populations are one of the dominating disturbance factors in North America's boreal forests and during outbreaks trees are often killed over vast forest areas. If the predicted shifts in climate occur, the damage patterns caused by insects may be considerably changed, particularly those of insects whose temporal and spatial distributions are singularly dependent on climatic factors. The ensuing uncertainties directly affect depletion forecasts, pest hazard rating procedures, and long-term planning for pest control requirements. Because the potential for wildfire often increases in stands after insect attack, uncertainties in future insect damage patterns also lead to uncertainties in fire regimes. In addition, because the rates of processes key to biogeochemical and nutrient recycling are influenced by insect damage, potential changes in damage patterns can indirectly affect ecosystem resilience and the sustainability of the multiple uses of the forest resource.

In this paper, a mechanistic perspective is developed based on available information describing how defoliating forest insects might respond to climate warming. Because of its prevalence and long history of study, the spruce budworm, Choristoneura fumiferana Clem. (Lepidoptera: Tortricidae), is used for illustrative purposes in developing this perspective. The scenarios that follow outline the potential importance of threshold behaviour, historical conditions, phenological relationships, infrequent but extreme weather, complex feedbacks, and natural selection. The urgency of such considerations is emphasized by reference to research suggesting that climate warming may already be influencing some insect lifecycles.

  • Fleming, ORCID ID:E-mail:
article id 5594, category Article
Anssi Niskanen, Tapio Rantala, Olli Saastamoinen. (1996). Economic impacts of carbon sequestration in reforestation: examples from boreal and moist tropical conditions. Silva Fennica vol. 30 no. 2–3 article id 5594. https://doi.org/10.14214/sf.a9239

The impact of carbon sequestration on the financial profitability of four tree plantation cases in Finland and the Philippines were examined. On the basis of stem wood growth; the accumulation of carbon in forest biomass, the formation and decomposition of litter, and the carbon flow in wood-based products were assessed for each reforestation case representing boreal (Finland) and moist tropical conditions (the Philippines). Using different unit values for carbon sequestration the profitability of reforestation was estimated for a fixed 100-year period on a per hectare basis. The financial profitability of reforestation increased notably when the sequestered carbon had high positive values. For example, when the value of carbon sequestration was set to be Twenty-five United States Dollar per megagram of carbon (25 USO/Mg C), the internal rate of return (IRR) of a reforestation investment with Norway spruce (Picea abies (L.) H. Karst.) in Finland increased from 3.2% to 4.1 %. Equally, the IRR of reforestation with mahogany (Swietenia macrophylla King) in the Philippines increased from 12.8% to 15.5%. The present value of carbon sequestration ranged from 39–48% and from 77–101% of the present value of the reforestation cost in Finland and the Philippines, respectively when a 25 USO/Mg C shadow price and a 5% discount rate were applied. Sequestration of one mg of carbon in reforestation in Finland and the Philippines was estimated to cost from 10.5–20.0 and from 4.0–13.6 USO, respectively.

  • Niskanen, ORCID ID:E-mail:
  • Rantala, ORCID ID:E-mail:
  • Saastamoinen, ORCID ID:E-mail:
article id 5590, category Article
Heikki Hänninen, Seppo Kellomäki, Ilkka Leinonen, Tapani Repo. (1996). Overwintering and productivity of Scots pine in a changing climate. Silva Fennica vol. 30 no. 2–3 article id 5590. https://doi.org/10.14214/sf.a9235

The productivity of Scots pine (Pinus sylvestris L.) under changing climatic conditions in the southern part of Finland was studied by scenario analysis with a gap-type forest ecosystem model. Standard simulations with the model predicted an increased rate of growth and hence increased productivity as a result of climatic warming. The gap-type model was refined by introducing an overwintering sub-model describing the annual growth cycle, frost hardiness, and frost damage of the trees. Simulations with the refined gap-type model produced results conflicting with those of the standard simulation, i.e., drastically decreased productivity caused by mortality and growth-reducing damage due to premature dehardening in the changing climate. The overwintering sub-model was tested with frost hardiness data from Scots pine saplings growing at their natural site 1) under natural conditions and 2) under elevated temperature condition, both in open-top chambers. The model predicted the frost hardiness dynamics quite accurately for the natural conditions while underestimating the frost hardiness of the saplings for the elevated temperature conditions. These findings show that 1) the overwintering sub-model requires further development, and 2) the possible reduction of productivity caused by frost damage in a changing climate is less drastic than predicted in the scenario analysis. The results as a whole demonstrated the need to consider the overwintering of trees in scenario analysis carried out with ecosystem model for boreal conditions. More generally, the results revealed a problem that exists in scenario analysis with ecological models: the accuracy of a model in predicting the ecosystem functioning under present climatic condition does not guarantee the realism of the model, nor for this reason the accuracy for predicting the ecosystem functioning under changing climatic conditions. This finding calls for the continuous rigorous experimental testing of ecological models used for assessing the ecological implications of climatic change.

  • Hänninen, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
  • Leinonen, ORCID ID:E-mail:
  • Repo, ORCID ID:E-mail:
article id 5589, category Article
Jouko Silvola, Urpo Ahlholm. (1996). Effects of CO2 concentration on the nutrition of willows (Salix phylicifolia) grown at different nutrient levels in organic-rich soil. Silva Fennica vol. 30 no. 2–3 article id 5589. https://doi.org/10.14214/sf.a9234

Willows (Salix phylicifolia) were grown for four months in organic rich soil at four nutrient levels (fertilization with a micronutrient-macronutrient mixture of 0, 100, 500 and 1,000 kg ha-1 per month) and four CO2 concentrations (300, 500, 700 and 1,000 ppm). Nitrogen and phosphorus concentration of the willows were reduced at CO2 enhancement, the decrease being larger in the leave and roots than in the stems. Nitrogen content of the willows plus extractable nitrate-N in the soil coincided well with the doses of nitrogen supplied, but the corresponding sum of phosphorus in the plants and soil were smaller. The total nitrogen content of willows grown in unfertilized soil was nearly two times higher than the sum of the extractable nitrate-N in soil and N content of the cutting at the beginning of the experiment. The contents of nitrogen and phosphorus of the unfertilized willows were independent of CO2 concentration, suggesting that CO2 concentration did not affect through increased mineralization the availability of those nutrients to the willows.

  • Silvola, ORCID ID:E-mail:
  • Ahlholm, ORCID ID:E-mail:
article id 5586, category Article
Robert A. Monserud, Olga V. Denissenko, Tatyana P. Kolchugina, Nadja M. Tchebakova. (1996). Change in Siberian phytomass predicted for global warming. Silva Fennica vol. 30 no. 2–3 article id 5586. https://doi.org/10.14214/sf.a9231

An equilibrium model driven by climatic parameters, the Siberian Vegetation Model, was used to estimate changes in the phytomass of Siberian vegetation under climate change scenarios (CO2 doubling) from four general circulation models (GCM's) of the atmosphere. Ecosystems were classified using a three-dimensional climatic ordination of growing degree days (above a 5 °C threshold), Budyko's dryness index (based on radiation balance and annual precipitation), and Conrad's continentality index. Phytomass density was estimated using published data of Bazilevich covering all vegetation zones in Siberia. Under current climate, total phytomass of Siberia is estimated to be 74.1 ± 2.0 Pg (petagram = 1,015 g). Note that this estimate is based on the current forested percentage in each vegetation class compiled from forest inventory data.

Moderate warming associated with the GISS (Goddard Institute for Space Studies) and OSU (Oregon State Univ.) projections resulted in a 23–26 % increase in phytomass (to 91.3 ± 2.1 Pg and 93.6 ± 2.4 Pg, respectively), primarily due to an increase in the productive Southern Taiga and Sub-taiga classes. Greater warming associated with the GFDL (General Fluid Dynamics Laboratory) and UKMO (United Kingdom Meteorological Office) projections resulted in a small 3–7 % increase in phytomass (to 76.6 ± 1.3 Pg and 79.6 ± 1.2 Pg, respectively). A major component of predicted change using GFDL and UKMO is the introduction of a vast Temperate Forest-Steppe class covering nearly 40% of the area of Siberia, at the expense of Taiga; with current climate, this vegetation class is nearly non-existent in Siberia. In addition, Sub-boreal Forest-Steppe phytomass double with all GCM predictions. In all four climate change scenarios, the predicted phytomass stock of all colder, northern classes is reduced considerably (viz., Tundra, Fore Tundra, northern Taiga, and Middle Taiga). Phytomass in Sub-taiga increases greatly with all scenarios, from a doubling with GFDL to quadrupling with OSU and GISS. Overall, phytomass of the Taiga biome (Northern, Middle, Southern and Sub-taiga) increased 15% in the moderate OSU and GISS scenarios and decreased by a third in the warmer UKMO and GFDL projections. In addition, a sensitivity analysis found that the percentage of a vegetation class that is forested is a major factor determining phytomass distribution. From 25 to 50% more phytomass is predicted under climate change if the forested proportion corresponding to potential rather than current vegetation is assumed.

  • Monserud, ORCID ID:E-mail:
  • Denissenko, ORCID ID:E-mail:
  • Kolchugina, ORCID ID:E-mail:
  • Tchebakova, ORCID ID:E-mail:
article id 5583, category Article
Ilkka Leinonen, Heikki Hänninen, Tapani Repo. (1996). Testing of frost hardiness models for Pinus sylvestris in natural conditions and in elevated temperature. Silva Fennica vol. 30 no. 2–3 article id 5583. https://doi.org/10.14214/sf.a9228

Two dynamic models predicting the development of frost hardiness of Finnish Scots pine (Pinus sylvestris L.) were tested with frost hardiness data obtained from trees growing in the natural conditions of Finland and from an experiment simulating the predicted climatic warming. The input variables were temperature in the first model, and temperature and night length in the second. The model parameters were fixed on the basis of previous independent studies. The results suggested that the model which included temperature and photoperiod as input variables was more accurate than the model using temperature as the only input variable to predict the development of frost hardiness in different environmental conditions. Further requirements for developing the frost hardiness models are discussed.

  • Leinonen, ORCID ID:E-mail:
  • Hänninen, ORCID ID:E-mail:
  • Repo, ORCID ID:E-mail:
article id 5582, category Article
Jonathan J. Ruel, Matthew P. Ayres. (1996). Variation in temperature responses among populations of Betula papyrifera. Silva Fennica vol. 30 no. 2–3 article id 5582. https://doi.org/10.14214/sf.a9227

How will global warming affect southern populations of boreal trees? In paper birch, Betula papyrifera (Betulaceae), alpine trees with an evolutionary history of relatively cool summers may be more sensitive to climate warming than valley populations. We evaluated this scenario by growing seedlings from different populations in four temperature treatments (mountain field site, valley field site, and two greenhouse rooms).

Populations from low elevations germinated earlier and had higher germination success than population from high elevations (16.8 vs. 22.0 d; 72% vs. 11%). At the valley site, seedlings from native populations grew faster than seedlings from higher elevations (mean ± SE = 0.25 ± 0.02 vs. 0.09 ± 0.04 mm · cm-1 · d-1) while at the mountain site, all seedlings grew at similar rates. Seedling grown in cooler environments had higher root : shoot ratios, perhaps to compensate for temperature limitations in nutrient uptake by roots. Leaf area varied among populations but was not affected by environmental differences across the field sites. Net photosynthetic rates at valley temperatures were higher for seedlings grown in the valley than for seedling grown in the mountains or the warm greenhouse (12.0 vs. 10.3 and 5.8 μmoles · m-2 · s-1), perhaps due to adaptive phenotypic adjustments. Climatic warming could rapidly produce important phenotypic changes in birch trees (e.g. decreased root : shoot ratio, reduced growth in alpine populations). On a longer time-scale, warming could also result in genetic changes as natural selection favours valley genotypes in alpine sites where they are presently rare.

  • Ruel, ORCID ID:E-mail:
  • Ayres, ORCID ID:E-mail:
article id 5581, category Article
Oddvar Skre, Knut Nes. (1996). Combined effects of elevated winter temperatures and CO2 on Norway spruce seedlings. Silva Fennica vol. 30 no. 2–3 article id 5581. https://doi.org/10.14214/sf.a9226

A total of 1,800 3-year old seedlings of Norway spruce (Picea abies (L.) H. Karst.) from two Norwegian and one German provenance were treated with two different nitrogen levels during the 1992 growth season. The plants were kept during the following winter at two different temperature levels. In the spring of 1993, the nutrient application was resumed, and the plants were divided between three different treatments, 350 and 650 p.p.m. in open top chamber and a control plot outside the chambers. This treatment was repeated also during the following 1994 growth season.

The growth and primary production were studied by photosynthesis experiments and by non-destructive growth measurements. The result indicate that raised winter temperature may lead to increased needle loss and reduced growth the following season, particularly in northern provenances. Carbon dioxide significantly influenced growth in addition to nutrient level and winter temperature. High CO2 also seemed to cause increased photosynthesis at early season, and earlier budbreak and growth cessation than in control plants.

  • Skre, ORCID ID:E-mail:
  • Nes, ORCID ID:E-mail:
article id 5561, category Article
Jari Liski. (1995). Variation in soil organic carbon and thickness of soil horizons within a boreal forest stand – effect of trees and implications for sampling. Silva Fennica vol. 29 no. 4 article id 5561. https://doi.org/10.14214/sf.a9212

Spatial variation in the density of soil organic carbon (kg/m2) and the thickness of soil horizons (F/H, E) were investigated in a 6 m x 8 m area in Scots pine (Pinus sylvestris L.) stand in Southern Finland for designing an effective sampling for the C density and studying the effect of trees on the variation. The horizon thickness of the podzolized soil were measured on a total of 126 soil cores (50 cm deep) and the C density of the organic F/H and 0–10 cm, 10–20 cm and 20–40 cm mineral soil layers was analysed.

The C density varied 3–5 fold within the layers and the coefficients of variation ranged from 22 % to 40%. Considering the gain in confidence per sample, 8–10 samples were suggested for estimating the mean C density in the F/H and 0–40 cm layers, although about 30 samples are needed for 10% confidence in the mean. The C densities and horizon thicknesses were spatially dependent within the distances of 1–8 m, the spatial dependence accounting for 43–86% of the total variance. The F/H layer was thicker and contained more C within 1–3 m radius from trees. In the 10–20 cm and 20–40 cm layers (B horizon) the C density also increased towards the trees, but more pronouncedly in the immediate vicinity of the stems. Because the spatial patterning of the E horizon thickness was similar, the increase was attributed to stemflow and precipitation of organic compounds in the podzol B horizon.

  • Liski, ORCID ID:E-mail:
article id 5551, category Article
Jyrki Hytönen, Pekka Rossi, Anna Saarsalmi. (1995). Biomass production and nutrient uptake of short-rotation plantations. Silva Fennica vol. 29 no. 2 article id 5551. https://doi.org/10.14214/sf.a9202

The biomass production and nutrient uptake of silver birch (Betula pendula Roth), downy birch (Betula pubescens Erhr.), grey alder (Alnus incana (L.) Moench), native willows Salix triandra L. and S. phylicifolia L. and exotic willows S. x dasyclados and S. ’Aquatica’ growing on a clay mineral soil field (Sukeva) and on two cut-away peatland areas (Piipsanneva, Valkeasuo) were investigated.

Biomass production of downy birch was greater than that of silver birch, and the biomass production of the native willows greater than that of the exotic ones. The performance of S. phylicifolia was the best of the studied willow species. Exotic willows were susceptible to frost damage and their winter hardiness was poor. The production of all species was lower on the clay mineral soil field than on the cut-away peatland areas. Fertilization of birches and alder – on the double dose given to the willows – increased biomass production. After 6 growing seasons the leafless biomass production of fertilized silver birch at Piipsanneca was 21 t ha-1 (at Valkeasuo 34 t ha-1) and of grey alder 24 t ha-1, and that of S. triandra after five growing seasons 31 t ha-1, S. phylicifolia 38 t ha-1 and of S. x dasyclados 16 t ha-1.

6-year-old stands of silver birch bound more nutrients per unit biomass than downy birch stands. Grey alder bound more N, Ca and Co but less Mn and Zn per unit biomass than silver and downy birch. On the field more P was bound in grey alder per unit biomass compared to downy birch. The willows had more K per unit biomass than the other tree species, and the exotic willow species more N than the native ones. Less N, K and Mg were bound per unit biomass of S. phylicifolia compared to the other tree species.

  • Hytönen, ORCID ID:E-mail:
  • Rossi, ORCID ID:E-mail:
  • Saarsalmi, ORCID ID:E-mail:
article id 5545, category Article
Jouni Siipilehto, Olavi Lyly. (1995). Weed control trials with fibre mulch, glyphosate and terbuthylazine in Scots pine plantations. Silva Fennica vol. 29 no. 1 article id 5545. https://doi.org/10.14214/sf.a9196

The following treatments were compared in three Scots pine (Pinus sylvestris L.) reforestation areas on a scarified moist mineral-soil site in southern Finland, planted with 1+1 bareroot stock in spring 1987: (a) no weed control treatment; (b) mulching with a fibre slurry produced by mixing wastepaper with water and applied 1 cm deep to an area of 60 cm in diameter around the seedling soon after planting; (c) glyphosate (at 2 kg ha-1) sprayed on a 1 m2 spot around the seedling in early August 1987; (d) terbuthylazine (at 10 kg ha-1) applied as (c). Monitoring of the trials over a 4-year period between 1987–90 showed that none of the treatments reduced surface vegetation to an extent that would have benefited pine. The percentage cover development of the vegetation, dominated by Agrostis capillaris, Calamagrostis arundinaceae, Deschampsia flexuosa, Festuca ovina, Epilobioum angustifolium and Pteridium aquillinum, followed much the same pattern in all treatments, with (c) slightly favouring forbs. Survival of pine at the end of the study period was about 90%, with non-significant differences between treatments. Mulching and terbuthylazine treatment slightly reduced seedling height growth in the second year. Growth was better in glyphosate treatment than in terbuthylazine treatment in the lowest (<30%) and the highest (>60%) pre-treatment weed cover classes, and in the latter also better than in untreated control. Mulching gave variable results; at its best it provided also good control of weeds for several years, without, however, improving the initial development of pine in these trials.

  • Siipilehto, ORCID ID:E-mail:
  • Lyly, ORCID ID:E-mail:
article id 5534, category Article
Hyun Kang, Inger Ekberg, Gösta Eriksson, Johan Ununger. (1994). Second and third growth period responses of Picea abies families to first growth period photoperiodic, light intensity and temperature treatments. Silva Fennica vol. 28 no. 4 article id 5534. https://doi.org/10.14214/sf.a9174

Seedlings of Picea abies (L.) H. Karst. full-sib families of contrasting origins were cultivated in a phytotron under different photoperiodic, light-intensity and temperature treatments during their first growth period. The effects of the treatments on juvenile growth traits – whether enhanced or delayed maturation was induces – were observed during the two subsequent growth periods. The following hypotheses were tested: (A) Enhanced maturation can be induced in the first growth period from sowing with (i) a long period of continuous light during active growth (24 weeks vs. 8 weeks); (ii) a shorter night during bud maturation (12 h vs. 16 h); high temperature (25°C vs. 20°C) during (iii) active growth, growth cessation and bud maturation; and during (iv) the latter part of growth cessation and bud maturation only. (B) Delayed maturation can be induced after (i) low light intensity during growth cessation and bud maturation (114 μmol m-2 s-1 vs. 340 μmol m-2 s-1); low temperature (15°C vs. 20°C) during (ii) active growth, growth cessation and bud maturation; and during (iii) the latter part of growth cessation and bud maturation only.

The most dramatic effect was observed after 24 weeks of continuous light during active growth. All traits showed a significantly more mature performance in the second growth period compared with the control. The effect for all but one trait was carried over to the third growth period. This is in accordance with the hypothesis that the activity of apical shoot meristems controls the maturation process. For the other treatments there was only weak or no support for the hypothesis of induction of enhanced or delayed maturation. Strong family effects were observed for all traits. Differential responses of the various latitudinal families were observed, suggesting that family effects must be considered to predict and interpret correctly how plants will respond to environmental effects.

  • Kang, ORCID ID:E-mail:
  • Ekberg, ORCID ID:E-mail:
  • Eriksson, ORCID ID:E-mail:
  • Ununger, ORCID ID:E-mail:
article id 5532, category Article
Anu Honkanen. (1994). Selection of Salix myrsinifolia clones for biomass forestry in Finland. Silva Fennica vol. 28 no. 3 article id 5532. https://doi.org/10.14214/sf.a9172

For biomass forestry in the inland parts of Southern and Central Finland, the obvious choice of willow species is Salix myrsinifolia. However, selection of clones of indigenous species has not yet been completed and more research and selection is needed. In the Piipsanneva old peatland trial, indigenous species of willow, mostly clones of S. myrsinifolia and S. phylicifolia, were compared in terms of biomass production, coppicing, height growth and diameter distributions. In this trial, the mean annual biomass production was not particularly high; more important results were attained in the ranking of clones. The trial strengthens the hypothesis that, over the long-term, the biomass production of S. myrsinifolia is higher than that of S. phylicifolia. It was supposed that behind the highest yield there was a clone with uniform quality, one whose diameter distribution would be narrow and positively skewed. Comparisons of parameters of Weibull functions showed that the distributions of the best clones were wide, indicating that those clones use the whole growth space better than those with narrow distribution.

  • Honkanen, ORCID ID:E-mail:
article id 5529, category Article
Jukka Lippu. (1994). Patterns of dry matter partitioning and 14C-photosynthate allocation in 1.5-year-old Scots pine seedlings. Silva Fennica vol. 28 no. 3 article id 5529. https://doi.org/10.14214/sf.a9169

Change in dry matter partitioning, 14C-incorporation, and sink 14C-activity of 1.5-year-old Scots pine (Pinus sylvestris L.) seedlings grown in growth chamber conditions were studied during a 91-day experiment. On five sampling dates, seedlings were labelled with 14CO2 and whole-plant allocation patterns were determined. Intensively growing shoots modified the dry matter partitioning: during shoot growth the proportion of roots decreased but after that it increased. Based on their large proportion of dry matter, the needles (excluding current needles) were the strongest sink of carbon containing 40% of the incorporated 14C. Despite their small initial sink size, the elongating shoots (current main shoot + current branch) and their needles were the second strongest sink (30–40% of the total 14C) which reflects their high physiological activity. The proportion of 14C in the current year’s main shoot increased during shoot growth but decreased as the growth began to decline after 70 days. 10–20% of the total assimilated 14C was translocated to the roots. Laterals above 2nd order were the strongest sink in the root system, containing twice as much 14C as the other roots together. Alternation between shoot and root growth can be seen clearly: carbon allocation to roots was relatively high before and after the period of intensive shoot growth. Changes in root sink strength resulted primarily from changes in root sink activity rather than sink size.

  • Lippu, ORCID ID:E-mail:
article id 5528, category Article
Pekka Tamminen, Michael Starr. (1994). Bulk density of forested mineral soils. Silva Fennica vol. 28 no. 1 article id 5528. https://doi.org/10.14214/sf.a9162

Relationships between bulk density and organic matter (OM) content, textural properties and depth are described for forested mineral soils from Central and Northern Finland. Core samples were taken of 0–5, 30–35 and 60–65 cm layers at 75 plots. Three measures of bulk density were calculated: the bulk density of the < 20 mm fraction (BD20), the bulk density of the < 2 mm fraction (BD2), and laboratory bulk density (BDl). BDl was determined from the mass of a fixed volume of < 2 mm soil taken in the laboratory. All three measures of bulk densities were strongly correlated with organic matter content (r ≥ -0.63). Depth and gravel (2–20 mm) content (in the case of BD2) were also important variables. BDl was sensitive to clay contents > 7% but did significantly improve the prediction of both BD2 and BD20 in coarse soils (clay contents ≤ 7%). Predictive models were derived for coarse soils.

  • Tamminen, ORCID ID:E-mail:
  • Starr, ORCID ID:E-mail:
article id 5526, category Article
Pertti. Hari, Pasi Aalto, Kaarle Hämeri, Markku. Kulmala, Tapani. Lahti, Sari. Luoma, Lauri Palva, Toivo Pohja, Erkki. Pulliainen, Erkki. Siivola, Timo Vesala. (1994). Air pollution in eastern Lapland : challenge for an environmental measurement station. Silva Fennica vol. 28 no. 1 article id 5526. https://doi.org/10.14214/sf.a9160

The Värriö environmental measurement station has been designed and constructed during 1991 and 1992. The measurement system consists of measurement units for gases (sulphur dioxide, ozone, carbon dioxide), particles, photosynthesis and irradiation. A meteorological station is also included. The preliminary measurement period was started on August, 1991. During the first year (1991–1992) some parts of the system were redeveloped and rebuilt. Full, continuous measurement started in August 1992. The system has been working quite reliably, with good accuracy. The preliminary results show that pollution episodes are observed when the wind direction is from Monchegorsk or Nikel, the main emission sources in Kola Peninsula.

  • Hari, ORCID ID:E-mail:
  • Aalto, ORCID ID:E-mail:
  • Hämeri, ORCID ID:E-mail:
  • Kulmala, ORCID ID:E-mail:
  • Lahti, ORCID ID:E-mail:
  • Luoma, ORCID ID:E-mail:
  • Palva, ORCID ID:E-mail:
  • Pohja, ORCID ID:E-mail:
  • Pulliainen, ORCID ID:E-mail:
  • Siivola, ORCID ID:E-mail:
  • Vesala, ORCID ID:E-mail:
article id 5526, category Article
Pertti. Hari, Pasi Aalto, Kaarle Hämeri, Markku. Kulmala, Tapani. Lahti, Sari. Luoma, Lauri Palva, Toivo Pohja, Erkki. Pulliainen, Erkki. Siivola, Timo Vesala. (1994). Air pollution in eastern Lapland : challenge for an environmental measurement station. Silva Fennica vol. 28 no. 1 article id 5526. https://doi.org/10.14214/sf.a9160

The Värriö environmental measurement station has been designed and constructed during 1991 and 1992. The measurement system consists of measurement units for gases (sulphur dioxide, ozone, carbon dioxide), particles, photosynthesis and irradiation. A meteorological station is also included. The preliminary measurement period was started on August, 1991. During the first year (1991–1992) some parts of the system were redeveloped and rebuilt. Full, continuous measurement started in August 1992. The system has been working quite reliably, with good accuracy. The preliminary results show that pollution episodes are observed when the wind direction is from Monchegorsk or Nikel, the main emission sources in Kola Peninsula.

  • Hari, ORCID ID:E-mail:
  • Aalto, ORCID ID:E-mail:
  • Hämeri, ORCID ID:E-mail:
  • Kulmala, ORCID ID:E-mail:
  • Lahti, ORCID ID:E-mail:
  • Luoma, ORCID ID:E-mail:
  • Palva, ORCID ID:E-mail:
  • Pohja, ORCID ID:E-mail:
  • Pulliainen, ORCID ID:E-mail:
  • Siivola, ORCID ID:E-mail:
  • Vesala, ORCID ID:E-mail:
article id 5513, category Article
Tapani Pöykkö, Pirkko Velling. (1993). Inheritance of the narrow-crowned Scots pine E 1101, "Kanerva pine". Silva Fennica vol. 27 no. 3 article id 5513. https://doi.org/10.14214/sf.a15674

There is some evidence to support the hypothesis that crown form of Scots pine (Pinus sylvestris L.) can be inherited either mono- or polygenically. In Finland, a narrow, horizontal whorl-layer structure is striking in about one half of the offspring of a genotype E 1101, ”Kanerva pine”. The offspring are characterized by a narrow crown, short and thin branches at an angle of 90° to the stem, minimal tapering and by numerous long, lateral shoots, long needles and the common occurrence of three-needled fascicles among the dwarf shoots. These features are connected to a high growth rate, a high harvest index and to tortuosity of the stem. It is suggested that this complex of characters is determined by a single dominant gene.

In this study, several offspring of the E 1101 were classified into three form types in seven sets of progeny test data, including progenies of various ages having E 1101 as either maternal or paternal parent as well as open pollinated progenies of second-generation offspring. A segregation close to 1:1 was found both in the first and in the second-generation progenies when wilds and intermediates were combined and compared with Kanervas. The result indicates that the three types of Kanerva form can be due to a single dominant allele (K). Kanervas are heterozygous (Kk) for the allele and wilds are recessive homozygotes (kk) resulting 1:1 segregation in their progenies. However, there were also remarkable deviations from the expected distribution. The differences as well as the inheritance pattern are discussed.

The PDF includes an abstract in Finnish.

  • Pöykkö, ORCID ID:E-mail:
  • Velling, ORCID ID:E-mail:
article id 5503, category Article
Juha Heiskanen. (1993). Variation in water retention characteristics of peat growth media used in tree nurseries. Silva Fennica vol. 27 no. 2 article id 5503. https://doi.org/10.14214/sf.a15664

The water retention characteristics and their variation in tree nurseries and related physical properties were determined for commercially produced growth media made of light slightly humified Sphagnum peat. A total of 100 samples of peat media were collected from filled seedling trays in the greenhouses of four Finnish nurseries in 1990. In addition, the physical properties were determined for two growth media made of compressed peat sheets and chips. The variation in water retention characteristics in nurseries was described using linear models with fixed and random effects. The sources of variation in the mixed linear models were producer, grade, batch (greenhouse) and sample (tray).

The water retention of the peat media at different matric potentials was comparable to that given in the literature. The media shrank an average of 0–16% during desorption. The peat grades were finer than the Nordic quality standards for peat growth media. Particles < 1 mm increased and particles 1–5 mm decreased the water retention characteristics measured. The greatest total variation in water retention was at -1 kPa. The water retention of the peat media differed least at -5 and -10 kPa. The water retention characteristics of media from different producers usually differed significantly. The grades, on the other hand, did not differ from each other in their water retention characteristics nor were there significant interactions between producer and grade. The batch effect was marked but was lower than the effect within batches, where the sample (tray) effect was greater than the effect due to random measurement error. At -10 kPa, the measurement error was, however, clearly greater than the sample effect. The random measurement error was comparable to the batch effect. Aeration of the growth media is dependent on the water content retained between saturation and -1 kPa. The water availability to seedlings at the nursery phase is affected mainly by water retention between -1 and -10 kPa.
The PDF includes an abstract in Finnish.

  • Heiskanen, ORCID ID:E-mail:
article id 5503, category Article
Juha Heiskanen. (1993). Variation in water retention characteristics of peat growth media used in tree nurseries. Silva Fennica vol. 27 no. 2 article id 5503. https://doi.org/10.14214/sf.a15664

The water retention characteristics and their variation in tree nurseries and related physical properties were determined for commercially produced growth media made of light slightly humified Sphagnum peat. A total of 100 samples of peat media were collected from filled seedling trays in the greenhouses of four Finnish nurseries in 1990. In addition, the physical properties were determined for two growth media made of compressed peat sheets and chips. The variation in water retention characteristics in nurseries was described using linear models with fixed and random effects. The sources of variation in the mixed linear models were producer, grade, batch (greenhouse) and sample (tray).

The water retention of the peat media at different matric potentials was comparable to that given in the literature. The media shrank an average of 0–16% during desorption. The peat grades were finer than the Nordic quality standards for peat growth media. Particles < 1 mm increased and particles 1–5 mm decreased the water retention characteristics measured. The greatest total variation in water retention was at -1 kPa. The water retention of the peat media differed least at -5 and -10 kPa. The water retention characteristics of media from different producers usually differed significantly. The grades, on the other hand, did not differ from each other in their water retention characteristics nor were there significant interactions between producer and grade. The batch effect was marked but was lower than the effect within batches, where the sample (tray) effect was greater than the effect due to random measurement error. At -10 kPa, the measurement error was, however, clearly greater than the sample effect. The random measurement error was comparable to the batch effect. Aeration of the growth media is dependent on the water content retained between saturation and -1 kPa. The water availability to seedlings at the nursery phase is affected mainly by water retention between -1 and -10 kPa.
The PDF includes an abstract in Finnish.

  • Heiskanen, ORCID ID:E-mail:
article id 5481, category Article
Pekka Nygren, Pertti Hari. (1992). Effect of foliar application with acid mist on the photosynthesis of potassium-deficient Scots pine seedlings. Silva Fennica vol. 26 no. 3 article id 5481. https://doi.org/10.14214/sf.a15642

The interactive effects of potassium deficit and foliar application with acid water (pH 5.5, 4.5, 4.0 and 3.0 given consecutively) on CO2 exchange rate of Pinus sylvestris L. seedlings was investigated in field conditions. No reduction of the CO2 exchange rate was observed in the seedlings supplied with sufficient potassium. Only the seedlings having the lowest needle K concentration (2.4 mgg-1) had an apparently low CO2 exchange rate before the applications with acid water. The CO2 exchange rate of most of the seedlings with low needle K concentration (3.9–6.0 mgg-1) decreased after the acid water application. The threshold acidity for the reduction varied between pH 4,0 and 3.0 depending on the needle K concentration. The reduction was more apparent at high irradiance. It was concluded that acid precipitation disturbs the CO2 exchange only in conditions of mineral nutrient deficit.

The PDF includes an abstract in Finnish.

  • Nygren, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
article id 5471, category Article
Hannu Fritze. (1992). Effects of environmental pollution on forest soil microflora - a review. Silva Fennica vol. 26 no. 1 article id 5471. https://doi.org/10.14214/sf.a15632

The article is a literature review focusing on the reaction of soil respiration, litter decomposition and microflora of forest soils to various pollutants like acidic deposition, heavy metals and unusual high amounts of basic cations. There is a great deal of evidence indicating that environmental pollution affects soil microbial activity and community structure. Much of the data originates from experimental designs where high levels of pollutants were applied to the soil under field or laboratory conditions. Furthermore, many were short-term experiments designed to look for large effects. These experiments have an indicative value, but it has to be kept in mind that environmental pollution is a combination of many pollutants, mostly at low concentrations, acting over long periods of time. There is therefore consequently a demand for research performed in natural forest environments polluted with anthropogenic compounds. 

  • Fritze, ORCID ID:E-mail:
article id 5465, category Article
Gösta Eriksson. (1991). Challenges for forest geneticists. Silva Fennica vol. 25 no. 4 article id 5465. https://doi.org/10.14214/sf.a15623

Studies of phenotypic as well as mixed population plasticities are urgently needed in a world that supposedly experiences a gradual change of its environment. It is important to understand that man creates his environment and silviculture. This is one of the reasons why for breeding it cannot be expected to find optimal phenotypes in nature. Other reasons are the phylogenetic constraints and migration of pollen and seeds.

Forest genetics up to now is characterized by the study of one trait at a time. There is an urgent need for simultaneous analysis of several traits by the aid of genetic correlations or multivariate analysis. Generally there is a need for inclusion of larger numbers of genetic entries in forest genetic investigations.

For the long-rotation-time species there is a need to determine the curves for degree of dormancy and hardiness during the annual cycle. Information of plasticity in two-dimensional environments like water availability and temperature is needed. Studies on nutrient utilization and acquisition will tell us whether or not we must have different breeding populations for different soil fertilities. An understanding of the phase changes between juvenile and adult opens up possible applications such as faster generation turn-over in the breeding population via early flowering and early testing as well as better plants for frost-prone and weedy sites.

  • Eriksson, ORCID ID:E-mail:
article id 5464, category Article
Donald I. Dickmann. (1991). Role of physiology in forest tree improvement. Silva Fennica vol. 25 no. 4 article id 5464. https://doi.org/10.14214/sf.a15622

The paper introduces different ways plant physiology research can avail the process of tree improvement. The breeding of tree cultivars that efficiently produce a particular wood product or amenity will be an important aspect of forest management. What physiologist can provide to breeders and genetic engineers is the opportunity to move their work from empirical level towards a more theoretical level, and help to make breeding more predictable and more precise in its objectives. The areas of research discussed in the paper are biotechnology, flowering, selection criteria, adaptability and application of ideotypes.

  • Dickmann, ORCID ID:E-mail:
article id 5461, category Article
Run-Peng Wei, Dag Lindgren. (1991). Selection effects on diversity and genetic gain. Silva Fennica vol. 25 no. 4 article id 5461. https://doi.org/10.14214/sf.a15619

Four different methods of truncation selection were studied in a population consisting of a large number of unrelated full sib families of equal size: phenotype selection, family selection, within-family selection and combined index selection (optimal weighting of individual and family performance to get the best prediction of breeding value). Methods were developed for calculating diversity (”relative effective family number”) for the different selection methods. Numerical calculations were made for genetic gain and diversity. Model assumptions are additive gene control and normal distribution. Phenotypic was good at high heritabilities and between family at low heritabilities. Loss of diversity was strongly dependent on selection method and selection strength. Compared at the same diversity, genetic gain was lower for combined index compared to phenotypic. There is a need for methods combining the goals gain and diversity.

The PDF includes an abstract in Finnish.

  • Wei, ORCID ID:E-mail:
  • Lindgren, ORCID ID:E-mail:
article id 5447, category Article
Jyrki Tomminen. (1991). Pinewood nematode, Bursaphelenchus xylophilus, found in packing case wood. Silva Fennica vol. 25 no. 2 article id 5447. https://doi.org/10.14214/sf.a15601

Living third dispersal stage juveniles of pinewood nematode, Bursaphelenchus xylophilus, were found infesting pine boards in Finland. The boards had been used as building material in a packing case to hold imported machinery. Total numbers of nematodes extracted from the boards did not exceed 4 grams of dry wood. When cultured on Botrytis cinerea the nematode reproduction resumed rapidly.

The PDF includes an abstract in Finnish.

  • Tomminen, ORCID ID:E-mail:
article id 5443, category Article
Raimo Silvennoinen, Rauno Hämäläinen, Kaarlo Nygrén, Kim von Weissenberg. (1991). Spectroradiometric characteristics of Scots pine and intensity of moose browsing. Silva Fennica vol. 25 no. 2 article id 5443. https://doi.org/10.14214/sf.a15597

The light reflected from the crowns of Scots pine (Pinus sylvestris L.) clones was measured spectroradiometrically during and after growing season. Standard deviations of the spectra of pine clones showing differences in moose browsing intensity were compared. A new algorithm was developed for predicting the browsing intensity of moose (Alces alces).

The PDF includes an abstract in Finnish.

  • Silvennoinen, ORCID ID:E-mail:
  • Hämäläinen, ORCID ID:E-mail:
  • Nygrén, ORCID ID:E-mail:
  • Weissenberg, ORCID ID:E-mail:
article id 5443, category Article
Raimo Silvennoinen, Rauno Hämäläinen, Kaarlo Nygrén, Kim von Weissenberg. (1991). Spectroradiometric characteristics of Scots pine and intensity of moose browsing. Silva Fennica vol. 25 no. 2 article id 5443. https://doi.org/10.14214/sf.a15597

The light reflected from the crowns of Scots pine (Pinus sylvestris L.) clones was measured spectroradiometrically during and after growing season. Standard deviations of the spectra of pine clones showing differences in moose browsing intensity were compared. A new algorithm was developed for predicting the browsing intensity of moose (Alces alces).

The PDF includes an abstract in Finnish.

  • Silvennoinen, ORCID ID:E-mail:
  • Hämäläinen, ORCID ID:E-mail:
  • Nygrén, ORCID ID:E-mail:
  • Weissenberg, ORCID ID:E-mail:
article id 5432, category Article
Risto Rikala, Helen J. Jozefek. (1990). Effect of dolomite lime and wood ash on peat substrate and development of tree seedlings. Silva Fennica vol. 24 no. 4 article id 5432. https://doi.org/10.14214/sf.a15586

Effect of dolomite lime and wood ash (0, 0.5, 1, 2, 4, 8 and 16 kg m-3) on the chemical composition of low humified Sphagnum peat was studied. Germination of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.) and silver birch (Betula pendula Roth) and the subsequent growth of these seedlings were investigated in a greenhouse experiment. Nutrient concentrations in shoots and roots of pine seedlings were also analysed. The pH of peat increased asymptotically from 3.8 to about 7.0 with increasing lime regimen and to about 8.0 with increasing ash regimen. Wood ash linearly increased electrical conductivity and P, K, and Ca concentrations of peat. Rate of germination, within 7 days, of pine and spruce was best at low pH (<5) while birch seeds had a slightly higher pH optimum (4–6). Germination capacity, within 21 days, was not affected by pH or application regimen of either lime or ash. Pine and spruce seedlings grew best with lime and ash doses of 0.5–2.0 kg m-3, the pH of peat being 4–5. Lime and ash treatments did not affect the growth of birch seedlings, but wood ash increased nutrient concentration of pine seedlings.

The PDF includes an abstract in Finnish.

  • Rikala, ORCID ID:E-mail:
  • Jozefek, ORCID ID:E-mail:
article id 5432, category Article
Risto Rikala, Helen J. Jozefek. (1990). Effect of dolomite lime and wood ash on peat substrate and development of tree seedlings. Silva Fennica vol. 24 no. 4 article id 5432. https://doi.org/10.14214/sf.a15586

Effect of dolomite lime and wood ash (0, 0.5, 1, 2, 4, 8 and 16 kg m-3) on the chemical composition of low humified Sphagnum peat was studied. Germination of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.) and silver birch (Betula pendula Roth) and the subsequent growth of these seedlings were investigated in a greenhouse experiment. Nutrient concentrations in shoots and roots of pine seedlings were also analysed. The pH of peat increased asymptotically from 3.8 to about 7.0 with increasing lime regimen and to about 8.0 with increasing ash regimen. Wood ash linearly increased electrical conductivity and P, K, and Ca concentrations of peat. Rate of germination, within 7 days, of pine and spruce was best at low pH (<5) while birch seeds had a slightly higher pH optimum (4–6). Germination capacity, within 21 days, was not affected by pH or application regimen of either lime or ash. Pine and spruce seedlings grew best with lime and ash doses of 0.5–2.0 kg m-3, the pH of peat being 4–5. Lime and ash treatments did not affect the growth of birch seedlings, but wood ash increased nutrient concentration of pine seedlings.

The PDF includes an abstract in Finnish.

  • Rikala, ORCID ID:E-mail:
  • Jozefek, ORCID ID:E-mail:
article id 5430, category Article
Winai Sirikul, Markku Kanninen. (1990). Shoot growth and its clonal variation in Pinus kesiya. Silva Fennica vol. 24 no. 3 article id 5430. https://doi.org/10.14214/sf.a15584

Shoot elongation of Pinus kesiya Royle ex Gordon was studied using 2-year old grafts in a clonal seed orchard of the Pine Improvement Centre, located at the Huey Bong Experimental Station near Chiangmai, Thailand (19° 17’ N, 99° 15’ E, 900 m a.s.l.).

The seed orchard had a completely randomized block design with 30 blocks and 80 single-tree plots (clones) in each block. Eleven clones in four blocks were selected out of the total of 80 grafts (clones). From each graft, three lateral branches at the height of 1.6 m from the ground level were selected. Thus, total of 109 branches were measured. Shoot length of branches was measured between July 3, 1983 and March 11, 1984 at approximately bi-weekly intervals. Method of classical growth analysis were used in describing the shoot growth.

The annual shoot growth pattern of P. kesiya exhibited two consecutive sigmoid growth curves, i.e. it consisted of two flushes of shoot elongation, both formed by free growth. Thus, the pattern of shoot growth resembled the caribaea pattern. However, the annual shoot was composed of summer and winter shoots. These could be distinguished from each other by the reproductive organs, which always occur on winter shoot. The shoot contributed 61% of the total annual shoot length.

There were significant differences in the pattern of shoot elongation between the studied clones, which may reflect differences in the adaptation to different environmental conditions.

The PDF includes an abstract in Finnish.

  • Sirikul, ORCID ID:E-mail:
  • Kanninen, ORCID ID:E-mail:
article id 5428, category Article
Jyrki Tomminen. (1990). Presence of Bursaphelenchus mucronatus (Nematoda: Aphelenchoididae) fourth dispersal stages in selected conifer beetles in Finland. Silva Fennica vol. 24 no. 3 article id 5428. https://doi.org/10.14214/sf.a15582

Four dispersal stages of the nematode Bursaphelenchus mucronatus (Nematoda: Aphelenchoididae) were surveyed in Finland during the summers 1989 and 1990 examining field collected conifer beetle (Coleopterea) adults of the following species: Monochamus sutor, M. galloprovincialis, Acanthocinus aedilis, Rhagium inquisitor, Asemum striatum, Spondylis buprestoides and Hylobius abietis. All but the last one (Curculionidae) belong to genus Cerambycidae. The two Monochamus species were the only ones carrying B. mucronatus fourth dispersal stages, total number of nematode larvae per beetle being higher in M. galloprovincialis. The frequency of infestation was 24% in M. galloprovincialis and 14% in M. sutor but the difference eas not statistically significant.

The PDF includes an abstract in Finnish.

  • Tomminen, ORCID ID:E-mail:
article id 5420, category Article
Toyohiro Miyazava, Jukka Laine. (1990). Effect of macroclimate on the development of Scots pine seedling stands on drained oligotrophic pine mires. Silva Fennica vol. 24 no. 2 article id 5420. https://doi.org/10.14214/sf.a15574

The influence of different fertilization treatments and ditch spacings on the height growth of young Scots pine (Pinus sylvestris L.) seedling stands growing under various climatic regimes were determined. Comparisons were made between naturally regenerated and planted seedling stands. The effective temperature sum had a stronger effect on the height growth of planted seedlings, and in Northern Finland the planted seedlings seemed to be influenced to a greater degree by the adverse climatic conditions. The heavier the dose of fertilizer that had been applied, the greater the difference in growth caused by macroclimate. A considerably larger proportion of natural seedlings were located on hummocks compared with that of planted seedlings, irrespective of the region. On plots with wider ditch spacings, seedlings growing on hummocks were superior in height growth to those on flat surfaces.

The PDF includes an abstract in Finnish.

  • Miyazava, ORCID ID:E-mail:
  • Laine, ORCID ID:E-mail:
article id 5416, category Article
Carl Johan Westman. (1990). Metsämaan fysikaaliset ja fysikaalis-kemialliset ominaisuudet CT-OMaT kasvupaikkasarjassa. Silva Fennica vol. 24 no. 1 article id 5416. https://doi.org/10.14214/sf.a15568
English title: Soil physical and physio-chemical properties of Finnish upland forest sites.
English keywords: site factors; fertility; podzols; porosity; CEC; pH

In soil profiles from a series of uplands of different site types bulk density, density of solids and porosity of soil were clearly related to soil organic matter content and its distribution in the soil profile. Soil organic matter contents were also strongly correlated to effective cation exchange capacity (CEC) and soil acidity. Site fertility was primarily related to the fine fraction (ø<0.06 mm) content in the C horizon and related properties (i.e. CEC). In the humus layer, the content of exchangeable bases and base saturation most strongly related to site fertility.

The PDF includes an abstract in English.

  • Westman, ORCID ID:E-mail:
article id 5415, category Article
Kim von Weissenberg. (1990). Värd-parasitförhållanden i skogliga ekosystem. Silva Fennica vol. 24 no. 1 article id 5415. https://doi.org/10.14214/sf.a15567
English title: Host-parasite relationships in forest ecosystems: A review.

Based on a survey of world literature it is concluded that 1) the better -researched epidemic forest pathosystems are caused by anthropogenic factors, 2) the systems most likely have a polygenic background, and 3) resistance breeding should maintain polygenic resistance with restrictive incorporation of oligogenic resistance. Corresponding objectives are valid in breeding programs of presently balanced pathosystems, which may turn epidemic if man causes changes in the gene pool and alters critical environmental conditions.

The PDF includes an abstract in English.

  • Weissenberg, ORCID ID:E-mail:
article id 5415, category Article
Kim von Weissenberg. (1990). Värd-parasitförhållanden i skogliga ekosystem. Silva Fennica vol. 24 no. 1 article id 5415. https://doi.org/10.14214/sf.a15567
English title: Host-parasite relationships in forest ecosystems: A review.

Based on a survey of world literature it is concluded that 1) the better -researched epidemic forest pathosystems are caused by anthropogenic factors, 2) the systems most likely have a polygenic background, and 3) resistance breeding should maintain polygenic resistance with restrictive incorporation of oligogenic resistance. Corresponding objectives are valid in breeding programs of presently balanced pathosystems, which may turn epidemic if man causes changes in the gene pool and alters critical environmental conditions.

The PDF includes an abstract in English.

  • Weissenberg, ORCID ID:E-mail:
article id 5414, category Article
Heikki Smolander, Seppo Kellomäki, Pauline Oker-Blom. (1990). Typpipitoisuuden vaikutus männyn neulasten fotosynteesiin ja verson itsevarjostukseen. Silva Fennica vol. 24 no. 1 article id 5414. https://doi.org/10.14214/sf.a15566
English title: The effect of nitrogen concentration on needle photosynthesis and within shoot shading in Scots pine.

A close relationship between photosynthetic capacity and nitrogen concentration of leaves is known to exist. In conifers, nitrogen also affects the pattern of mutual shading within a shoot, which is a basic unit used in studying photosynthesis of coniferous trees. These effects of needle nitrogen concentration on photosynthetic capacity and mutual shading of needles were analysed for Scots pine (Pinus sylvestris L.) shoots taken from five young stands growing on sites of different fertility. The effect of nitrogen concentration on needle photosynthesis was studied based on measurements of the photosynthetic radiation response of shoots from which two thirds of the needles were removed in order to eliminate the effect of within shading.

An increase of one percentage unit in nitrogen concentration of needles increased the photosynthetic capacity of needles by 25 mg CO2 dm-2h-1. The effect of nitrogen on within-shoot shading was quantified in terms of the silhouette area to total needle area ratio of a shoot (STAR), which determines the relative interception rate per unit of needle area on the shoot. Although nitrogen promoted needle growth, an increase in nitrogen concentration decreased the within-shoot shading. This effect resulted from a decrease in needle density on the shoot and an increased needle angle with increasing nitrogen content.

The PDF includes an abstract in Finnish.

  • Smolander, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
  • Oker-Blom, ORCID ID:E-mail:
article id 5409, category Article
Jukka Lippu, Pasi Puttonen. (1990). Istutustaimen juuriston alkukehitys kasvupaikalla. Silva Fennica vol. 24 no. 1 article id 5409. https://doi.org/10.14214/sf.a15561
English title: The early development of seedling roots at the planting site: A literature review.

The structure and functional responses of roots in planted seedlings when acclimatizing at the planting site are reviewed. A wide range of methods for classifying roots has been employed, and the terminology used is not uniform. Roots can be classified by their morphology, origin, and function. The temporal and spatial variation of soil temperature, moisture, structure, and concentration of nutrients are among the most important properties to which root systems acclimatize. In order to reliably describe the function of the root system, several parameters usually have to be measured. Studies on the root-soil interface have indicated that roots are not necessarily in continuous contact with soil. The control mechanism of root growth is inadequately known and theoretically formulated. Generally, only the mass needed for water and nutrient uptake has been allocated to the roots. However, the amount of photosynthates allocated to the roots is high. Acclimatization of seedlings out at the planting site is a complicated process which is influenced by the growing conditions at both the nursery and at the site. The function, distribution and structure of roots are controlled by the environment in a way similar to the shoot, but the control mechanism is imperfectly known.

The PDF includes an abstract in English.

  • Lippu, ORCID ID:E-mail:
  • Puttonen, ORCID ID:E-mail:
article id 5405, category Article
Pertti Hari, Eeva Korpilahti, Toivo Pohja, Pentti K. Räsänen. (1990). A field system for measuring the gas exchange of forest trees. Silva Fennica vol. 24 no. 1 article id 5405. https://doi.org/10.14214/sf.a15557

A third generation of forest tree gas exchange measuring system design for the use in the field is described. The system is designed to produce data for determining the dependence of the rate of tree photosynthesis, respiration and transpiration on environmental factors. The system consists of eight cuvettes, a tubing system, two infrared gas analysers, an air flow controller, a data logger, and a computer. The measuring cuvette is a clap type, i.e. it is mostly open, only closing during measurement. CO2 exchange is measured as the change in the cuvette concentration of CO2, and, transpiration is measured as the increase in water vapour concentration while the cuvette is closed. The environmental factors measured are temperature, irradiance and air pressure. The system was planned in 1987 and constructed in 1988. It worked reliably in late summer 1988 and the quality of data seems to be satisfactory. 

The PDF includes an abstract in Finnish.

  • Hari, ORCID ID:E-mail:
  • Korpilahti, ORCID ID:E-mail: eeva.korpilahti@luke.fi
  • Pohja, ORCID ID:E-mail:
  • Räsänen, ORCID ID:E-mail:
article id 7109, category Article
Aimo Kaarlo Cajander. (1923). Einige Hauptzüge der pflanzentopographischen Forschungsarbeit in Finnland. Acta Forestalia Fennica vol. 23 no. 10 article id 7109. https://doi.org/10.14214/aff.7109
English title: Some outlines of plant topographical studies in Finland.

The text is a presentation given on the occasion of the yearly meeting of the Finnish Academy of Science and Letters on April 10th 1922. It presents the development of the plant topographic research in Finland with the most influential research and authors and their principal work.

The retrospect covers the publications between 1673 and 1917
  • Cajander, ORCID ID:E-mail:
article id 7107, category Article
J. P. Norrlin. (1923). Adnotationes de Pilosellis Fennicis. I. Aufzeichnungen über die Pilosellae Finnlands. I. Acta Forestalia Fennica vol. 23 no. 8 article id 7107. https://doi.org/10.14214/aff.7107
English title: Adnotationes de Pilosellis Fennicis. I Notices on Pilosellae (Hieracia sp.) (hawkweed) in Finland.

The article begins on the page 105/122 of the PDF file.

The article deals with the morphology of Hieracia sp. and their research, especially with Pilosella officinarum, also Hieracium pilosella. The article gives an overview of the most common, wide spread or otherwise remarkable forms of the genus of the Pilosella and reports, starting from the smallest areas, about the formula, distribution, abundance and occurrence of them.

The great amount of forms, their high variability and the tendency to hybridize make the definition of the varieties difficult.  However, the number of varieties in Finland is estimated to be between 150 and 200. The phenotype of the plant is also to some extent dependent on the site. The numerous forms that belong to the group of Piloselloideae can be divided in to groups: main species and intermediate forms. 

  • Norrlin, ORCID ID:E-mail:
article id 7107, category Article
J. P. Norrlin. (1923). Adnotationes de Pilosellis Fennicis. I. Aufzeichnungen über die Pilosellae Finnlands. I. Acta Forestalia Fennica vol. 23 no. 8 article id 7107. https://doi.org/10.14214/aff.7107
English title: Adnotationes de Pilosellis Fennicis. I Notices on Pilosellae (Hieracia sp.) (hawkweed) in Finland.

The article begins on the page 105/122 of the PDF file.

The article deals with the morphology of Hieracia sp. and their research, especially with Pilosella officinarum, also Hieracium pilosella. The article gives an overview of the most common, wide spread or otherwise remarkable forms of the genus of the Pilosella and reports, starting from the smallest areas, about the formula, distribution, abundance and occurrence of them.

The great amount of forms, their high variability and the tendency to hybridize make the definition of the varieties difficult.  However, the number of varieties in Finland is estimated to be between 150 and 200. The phenotype of the plant is also to some extent dependent on the site. The numerous forms that belong to the group of Piloselloideae can be divided in to groups: main species and intermediate forms. 

  • Norrlin, ORCID ID:E-mail:
article id 7105, category Article
J. P. Norrlin. (1923). Übersicht der Moose und Flechten von Torneå- (Muonio-) und den angrenzenden Teilen von Kemi-Lappmark. Acta Forestalia Fennica vol. 23 no. 6 article id 7105. https://doi.org/10.14214/aff.7105
English title: Overview of moos and lichen in Tornio-Muonio and the bordering parts of Kemi-Lappmark in Finnish Lapland.

The article begins on the page 91/122 of the PDF file.

The data has been collected during summer 1867. It examines the moos and lichen species in for regions of Lapland: spruce region, pine region, birch region and fjeld region. The division of the regions is related to the climatic and biological conditions of areas, the first mentioned being the most southern and still suitable e.g. for many grasses. Respective regions have been presented with their general characters and list of species. Finally the findings of different regions are compared.   

  • Norrlin, ORCID ID:E-mail:
article id 7105, category Article
J. P. Norrlin. (1923). Übersicht der Moose und Flechten von Torneå- (Muonio-) und den angrenzenden Teilen von Kemi-Lappmark. Acta Forestalia Fennica vol. 23 no. 6 article id 7105. https://doi.org/10.14214/aff.7105
English title: Overview of moos and lichen in Tornio-Muonio and the bordering parts of Kemi-Lappmark in Finnish Lapland.

The article begins on the page 91/122 of the PDF file.

The data has been collected during summer 1867. It examines the moos and lichen species in for regions of Lapland: spruce region, pine region, birch region and fjeld region. The division of the regions is related to the climatic and biological conditions of areas, the first mentioned being the most southern and still suitable e.g. for many grasses. Respective regions have been presented with their general characters and list of species. Finally the findings of different regions are compared.   

  • Norrlin, ORCID ID:E-mail:
article id 7105, category Article
J. P. Norrlin. (1923). Übersicht der Moose und Flechten von Torneå- (Muonio-) und den angrenzenden Teilen von Kemi-Lappmark. Acta Forestalia Fennica vol. 23 no. 6 article id 7105. https://doi.org/10.14214/aff.7105
English title: Overview of moos and lichen in Tornio-Muonio and the bordering parts of Kemi-Lappmark in Finnish Lapland.

The article begins on the page 91/122 of the PDF file.

The data has been collected during summer 1867. It examines the moos and lichen species in for regions of Lapland: spruce region, pine region, birch region and fjeld region. The division of the regions is related to the climatic and biological conditions of areas, the first mentioned being the most southern and still suitable e.g. for many grasses. Respective regions have been presented with their general characters and list of species. Finally the findings of different regions are compared.   

  • Norrlin, ORCID ID:E-mail:
article id 5389, category Article
Jyrki Tomminen, Matti Nuorteva, Markku Pulkkinen, Jouni Väkevä. (1989). Occurrence of the nematode Bursaphelenchus mucronatus Mamiya & Enda 1979 (Nematoda: Aphelenchoididae) in Finland. Silva Fennica vol. 23 no. 4 article id 5389. https://doi.org/10.14214/sf.a15547

A survey was conducted in Finland in 1988 to determine whether the pine wood nematode Bursaphelenchus mucronatus Mamiya & Enda 1979 (Nematoda: Aphelenchoididae) or the closely related species B. mucronatus would occur in Finnish forests. Dead or dying standing trees and timber of two conicer species, Pinus sylvestris L. (Scots pine) and Picea abies (L.) H. Karst. (Norway spruce) were analysed for the presence of these nematodes. Monochamus spp. pine sawyers (Coleoptera: Cerambycidae) were also collected and inspected for the presence of dispersal fourth juvenile stages (dauerlarva) of the nematodes. The species B. xylophilus was not found, but B. mucronatus appeared to be widespread in the country. Individuals of this nematode were found both from Scots pine and Norway spruce. Adults of two Monochamus species were found, M. galloprovincialis and M. sutor. Only two of the examined beetles of the former species had dauerlarvae in their body.

The PDF includes an abstract in Finnish.

  • Tomminen, ORCID ID:E-mail:
  • Nuorteva, ORCID ID:E-mail:
  • Pulkkinen, ORCID ID:E-mail:
  • Väkevä, ORCID ID:E-mail:
article id 5389, category Article
Jyrki Tomminen, Matti Nuorteva, Markku Pulkkinen, Jouni Väkevä. (1989). Occurrence of the nematode Bursaphelenchus mucronatus Mamiya & Enda 1979 (Nematoda: Aphelenchoididae) in Finland. Silva Fennica vol. 23 no. 4 article id 5389. https://doi.org/10.14214/sf.a15547

A survey was conducted in Finland in 1988 to determine whether the pine wood nematode Bursaphelenchus mucronatus Mamiya & Enda 1979 (Nematoda: Aphelenchoididae) or the closely related species B. mucronatus would occur in Finnish forests. Dead or dying standing trees and timber of two conicer species, Pinus sylvestris L. (Scots pine) and Picea abies (L.) H. Karst. (Norway spruce) were analysed for the presence of these nematodes. Monochamus spp. pine sawyers (Coleoptera: Cerambycidae) were also collected and inspected for the presence of dispersal fourth juvenile stages (dauerlarva) of the nematodes. The species B. xylophilus was not found, but B. mucronatus appeared to be widespread in the country. Individuals of this nematode were found both from Scots pine and Norway spruce. Adults of two Monochamus species were found, M. galloprovincialis and M. sutor. Only two of the examined beetles of the former species had dauerlarvae in their body.

The PDF includes an abstract in Finnish.

  • Tomminen, ORCID ID:E-mail:
  • Nuorteva, ORCID ID:E-mail:
  • Pulkkinen, ORCID ID:E-mail:
  • Väkevä, ORCID ID:E-mail:
article id 7102, category Article
J. P. Norrlin. (1923). Beiträge zur Flora des südöstlichen Tavastlands. Acta Forestalia Fennica vol. 23 no. 3 article id 7102. https://doi.org/10.14214/aff.7102
English title: Writings on the flora of south-eastern Tavastia province.
Original keywords: Tavastland; Flora; Vegetation; Phanerogamen

The article begins on the page 8/122 of the PDF file.

Data for this paper have been collected during years between 1859 and 1862 in the communes of Asikkala, Hollola, Padasjoki, Lammi and Koski. 

The first part of the text deals with a general presentation of the geographical, biological and cultural conditions of the studied areas. The second part presents the vegetation according their habitats; they are classified by the degree of moisture. The last is further classified as forested areas or open lands. The examination concentrates on phanerogams (seed plants).   

The characteristics of vegetation of forests, open lands and paludified places (swampy or swamp forming places) are presented with the most influential characters and lists of species.   

  • Norrlin, ORCID ID:E-mail:
article id 7102, category Article
J. P. Norrlin. (1923). Beiträge zur Flora des südöstlichen Tavastlands. Acta Forestalia Fennica vol. 23 no. 3 article id 7102. https://doi.org/10.14214/aff.7102
English title: Writings on the flora of south-eastern Tavastia province.
Original keywords: Tavastland; Flora; Vegetation; Phanerogamen

The article begins on the page 8/122 of the PDF file.

Data for this paper have been collected during years between 1859 and 1862 in the communes of Asikkala, Hollola, Padasjoki, Lammi and Koski. 

The first part of the text deals with a general presentation of the geographical, biological and cultural conditions of the studied areas. The second part presents the vegetation according their habitats; they are classified by the degree of moisture. The last is further classified as forested areas or open lands. The examination concentrates on phanerogams (seed plants).   

The characteristics of vegetation of forests, open lands and paludified places (swampy or swamp forming places) are presented with the most influential characters and lists of species.   

  • Norrlin, ORCID ID:E-mail:
article id 7102, category Article
J. P. Norrlin. (1923). Beiträge zur Flora des südöstlichen Tavastlands. Acta Forestalia Fennica vol. 23 no. 3 article id 7102. https://doi.org/10.14214/aff.7102
English title: Writings on the flora of south-eastern Tavastia province.
Original keywords: Tavastland; Flora; Vegetation; Phanerogamen

The article begins on the page 8/122 of the PDF file.

Data for this paper have been collected during years between 1859 and 1862 in the communes of Asikkala, Hollola, Padasjoki, Lammi and Koski. 

The first part of the text deals with a general presentation of the geographical, biological and cultural conditions of the studied areas. The second part presents the vegetation according their habitats; they are classified by the degree of moisture. The last is further classified as forested areas or open lands. The examination concentrates on phanerogams (seed plants).   

The characteristics of vegetation of forests, open lands and paludified places (swampy or swamp forming places) are presented with the most influential characters and lists of species.   

  • Norrlin, ORCID ID:E-mail:
article id 5385, category Article
Timo Kuuluvainen. (1989). Branching dynamics in young Scots pine. Silva Fennica vol. 23 no. 3 article id 5385. https://doi.org/10.14214/sf.a15542

The development of shoot number and shoot properties was examined in successive shoot cohorts of young widely-spaced Scots pine trees (Pinus sylvestris L.) growing in a progeny trial. This was accomplished by reconstructing the branching process of the trees over a period of five years, from tree age 4 to 8. During this time the number of shoots in successive shoot cohorts increased rapidly, while at the same time the mean shoot length decreased. The decrease in shoot lengths from older to younger shoots was accompanied by a decline in the bifuraction frequency of the shoots. In general, rapid changes occurred in the branching characteristics during the yearly development of the trees. The variation in the branching characteristics was reflected in the development of the architecture and biomass production of the trees.

The PDF includes an abstract in Finnish.

  • Kuuluvainen, ORCID ID:E-mail:
article id 7101, category Article
J. P. Norrlin. (1923). Lectio praecursoria, gehalten von J. P. Norrlin bei seiner Disputation am 13. Mai 1871. Acta Forestalia Fennica vol. 23 no. 2 article id 7101. https://doi.org/10.14214/aff.7101
English title: Lectio praecursoria (the opening presentation) of J. P. Norrlin at his public defence of a doctoral thesis on may 13th 1871.

The text is the opening presentation by the author at his public defence of his doctoral thesis on plant geography of Finland. The text discusses the principles that apply on plant geographical classification of earth with respect to characteristics of vegetation and gives an oversight on the plant geographical work conducted in Scandinavia. 

  • Norrlin, ORCID ID:E-mail:
article id 7101, category Article
J. P. Norrlin. (1923). Lectio praecursoria, gehalten von J. P. Norrlin bei seiner Disputation am 13. Mai 1871. Acta Forestalia Fennica vol. 23 no. 2 article id 7101. https://doi.org/10.14214/aff.7101
English title: Lectio praecursoria (the opening presentation) of J. P. Norrlin at his public defence of a doctoral thesis on may 13th 1871.

The text is the opening presentation by the author at his public defence of his doctoral thesis on plant geography of Finland. The text discusses the principles that apply on plant geographical classification of earth with respect to characteristics of vegetation and gives an oversight on the plant geographical work conducted in Scandinavia. 

  • Norrlin, ORCID ID:E-mail:
article id 5377, category Article
Maija Jarva, Arja Tervahauta. (1989). Neulasten rikkianalyysi. Silva Fennica vol. 23 no. 2 article id 5377. https://doi.org/10.14214/sf.a15534
English title: A comparison of sulphur analysis of conifer needle samples.

The results of an intercalibration of sulphur analysis by 24 laboratories are evaluated. The analysis was made by one or more of six methods. The following three methods were found to be satisfactory as regards relative speed and reliability: Leco S analysis, X-ray fluorescence, and vacuum ICO emission spectroscopy.

The PDF includes an abstract in English.

  • Jarva, ORCID ID:E-mail:
  • Tervahauta, ORCID ID:E-mail:
article id 7100, category Article
Aimo Kaarlo Cajander. (1923). Gedächtnisrede für Johan Petter Norrlin, gehalten in der Versammlung der Finnischen Wissenschaftsozietät am 10 Mai 1918. Acta Forestalia Fennica vol. 23 no. 1 article id 7100. https://doi.org/10.14214/aff.7100
English title: Commemorative speech in honor of Johan Peter Norrlin, given in the meeting of the “Finnish Society of Sciences and Letters” on May 10th 1918.

The here published speech of Cajander presents the academic career of J. P. Norrlin as a researcher, teacher and influential person in the Finnish scientific society. It also sheds light on Norrlin’s person and thoughts. The highlights of his scientific merits are presented. There are many extracts of his correspondence included in the article that describe Norrlin’s thoughts and interest. 

  • Cajander, ORCID ID:E-mail:
article id 5368, category Article
Kari Heliövaara, Rauno Väisänen. (1989). Invertebrates of young Scots pine stands near the industrial town of Harjavalta, Finland. Silva Fennica vol. 23 no. 1 article id 5368. https://doi.org/10.14214/sf.a15527

Invertebrates of young Scots pine (Pinus sylvestris L.) stands were preliminarily studied along a gradient of industrial air pollutants in Harjavalta, south-western Finland. Bark samples and net samples on pine branches and needles were taken in May–June, 1987. The number of aphids on needles was highest near the industrial plants. The number of mites in bark was positively correlated with the increasing distance from the pollutant source. Detrended correspondence analysis ordination calculated according to the bark invertebrates showed that the sampling sites of the zones far from the emission source formed a distinct group while those of the zones near the source were relatively widely dispersed indicating disturbances in faunal structure.

The PDF includes an abstract in Finnish.

  • Heliövaara, ORCID ID:E-mail:
  • Väisänen, ORCID ID:E-mail:
article id 5355, category Article
Halvor Rostad. (1988). Frost resistance during shoot elongation in Picea abies seedlings in relation to the growth environment of the previous growing period. Silva Fennica vol. 22 no. 3 article id 5355. https://doi.org/10.14214/sf.a15512

Frost resistance during shoot elongation in seedlings of Norway spruce (Picea abies (L.) H. Karst.) was studied in two experiments. The aim of the first study was to evaluate the effect of varying mineral nutrition. Except for potassium, only minor differences in mineral elements concentrations were established, presumably due to low levels of irradiance and thus a low rate of dry matter production. No significant differences in frost injuries were found between the treatments in the experimental series, but the control seedlings were significantly less injured. It is assumed that poor hardiness development at the end of one growth period resulting from low levels of irradiance may decrease the frost resistance during the next shoot elongation phase. Observations from the second experiment with Norway spruce nursery stocks representing different seedling ages and production systems, support this assumption.

The PDF includes an abstract in Finnish.

  • Rostad, ORCID ID:E-mail:
article id 5352, category Article
Lars Christersson, Heinrich A. von Fircks. (1988). Injuries to conifer seedlings caused by simulated summer frost and winter desiccation. Silva Fennica vol. 22 no. 3 article id 5352. https://doi.org/10.14214/sf.a15509

Visible frost damage to forest trees in Sweden seldom occurs in winter but is frequent in late spring, summer and early autumn. Frosts are frequent in all seasons in various parts of Sweden, even in the southernmost part (lat. 56°, N) and temperatures may be as low as -10°C even around mid-summer. Ice crystal formation within the tissues, which in most seedlings takes place at around -2°C, causes injury, not the sub-zero temperatures themselves.

The apical meristem, the elongated zone, and the needles of seedlings of Picea abies (L.) H. Karst. in a growing phase were damaged at about -3°C and those of Pinus sylvestris L. at about -6°C. Other species of the genus Pinus were tested and most were found to be damaged at about -6°C, with some variations. Picea species tested were damaged at about -3°C to -4°C.

A method has been designed to compare the response of different species to winter desiccation, which occurs under conditions of (1) low night temperature, (2) very high irradiation and increase in needle temperature during the photoperiod, (3) frozen soil, and (4) low wind speed. There were differences in response to winter desiccation between pine and spruce species. Seedlings of Pinus contorta tolerated these winter desiccation conditions much better than those of P. sylvestris or Picea abies. Picea mariana was the least tolerant of the species tested.

The PDF includes an abstract in Finnish.

  • Christersson, ORCID ID:E-mail:
  • Fircks, ORCID ID:E-mail:
article id 5351, category Article
Tapani Repo. (1988). Physical and physiological aspects of impedance measurements in plants. Silva Fennica vol. 22 no. 3 article id 5351. https://doi.org/10.14214/sf.a15508

Electrical impedance characteristics of plant cells are dependent on such physiological factors as physiological condition, developmental stage, cell structure, nutrient status, water balance and temperature acclimation. In the measurements also such technical and physical factors as type of electrodes, frequency, geometry of the object, inter-electrode distance and temperature have an effect. These factors are discussed especially with respect to the impedance method in frost resistance studies of plants.

The PDF includes an abstract in Finnish.

  • Repo, ORCID ID:E-mail:
article id 5348, category Article
Risto Häkkinen, Pertti Hari. (1988). The efficiency of time and temperature driven regulation principles in plants at the beginning of the active period. Silva Fennica vol. 22 no. 2 article id 5348. https://doi.org/10.14214/sf.a15505

The distribution of the minimum temperatures after the beginning of the active period (one temperature for each spring) have been calculated for each principle using daily meteorological data collected during the years 1883–1980. The efficiency criterion is the variance of the minimum temperature distributions and the length of the active period. The most efficient regulation principle is found to be based on the temperature sum which includes a feedback component.

The PDF includes a summary in Finnish.

  • Häkkinen, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
article id 5308, category Article
Martti Saarilahti, R. E. L. Ole-Meiludie. (1987). Production rate and work strain on workers in cutting of pines in Tanzania. Silva Fennica vol. 21 no. 1 article id 5308. https://doi.org/10.14214/sf.a15465

A team of 2 experienced workers was time-studied and their heart rate recorded under 4 days in clearcutting of a highly self-pruned Pinus patula Schltdl. & Cham. plantation. Task work and bonus payment systems were compared, but there was no difference in production rate, only the workplace time was extended from 2.3 h/d in task work to 3.9 h/d in bonus payment. The heart rate was 115–116 P/min in felling, 105–109 P/min in debranching and 109–114 P/min in bucking. The average heart rate in timber cutting was 108–109 P/min. Work load index was 34–37%, and the workers did not show any symptoms of accumulated stress. The production rate was 3.2 m3/h, (WPT, crew), which corresponds average piecework rate, the comparable walking speed being about 6.0 km/h. There are possibilities to increase the daily task by ergonomic grounds.

The PDF includes an abstract in Finnish.

  • Saarilahti, ORCID ID:E-mail:
  • Ole-Meiludie, ORCID ID:E-mail:
article id 5307, category Article
Simo Poso, Raito Paananen, Markku Similä. (1987). Forest inventory by compartments using satellite imagery. Silva Fennica vol. 21 no. 1 article id 5307. https://doi.org/10.14214/sf.a15464

A method for using satellite data in forest inventories and updating is described and tested. The stand characteristics estimated by the method showed high correlation with the same characteristics measured in the field. The correlation coefficients for volume, age and mean height were about 0.85. It seems that the method is applicable to practical forestry. Extensive work in programming, however, is required.

The PDF includes an abstract in Finnish.

  • Poso, ORCID ID:E-mail:
  • Paananen, ORCID ID:E-mail:
  • Similä, ORCID ID:E-mail:
article id 5303, category Article
Hannu Raitio. (1987). Neulasvuosikertojen merkitys neulasanalyysin tulkinnassa. Silva Fennica vol. 21 no. 1 article id 5303. https://doi.org/10.14214/sf.a15460
English title: The significance of the number of needle year classes of Scots pine in interpreting needle analysis results.

This study deals with significance of the number of needle year classes in estimating the nitrogen, phosphorus, potassium and magnesium status of Scots pine (Pinus sylvestris L.) plants on the basis of needle analysis. Due to the nutrient retranslocation deficiencies in these nutrients are best determined by analysing separately the needles of the topmost branch whorls possessing one, two or three needle year classes. The concentrations of those nutrients which are not scarce will then increase as needle year classes decrease. In cases of deficiency, on the other hand, the content of the nutrient concerned will remain the same or decrease. Only severe deficiencies are revealed by the examination of the nutrient concentrations of only the youngest or the oldest needles.

The PDF includes an abstract in English.

  • Raitio, ORCID ID:E-mail:
article id 5275, category Article
Pirkko Velling, Gérard Nepveu. (1986). Männyn puuaineen laadun ja tuotoksen vaihtelu suomalaisessa provenienssikoesarjassa. Silva Fennica vol. 20 no. 3 article id 5275. https://doi.org/10.14214/sf.a15454
English title: Variation of wood quality and yield in a Finnish series of provenance trials on Scots pine.

The purpose of the study was to determine the effects of the origin of seeds and the location of cultivation of Scots pine (Pinus sylvestris L.) on certain properties particularly important to the pulp industry. The research material consisted of six parallel trials of the same 12 provenances. Increment cores were taken of a total of 1,267 sample trees, 19 years old. The location of the trial site generally affected the properties to a larger extent than the origin of the seed. The effect of the variation of wood density and fibre yield on the cultivation values of the provenances was only a few percentages on average, however, at most the effect was nearly 10%. Eastern Finnish provenances adapted well to western Finnish conditions.

The PDF includes an abstract in Finnish and French.

  • Velling, ORCID ID:E-mail:
  • Nepveu, ORCID ID:E-mail:
article id 7062, category Article
Aimo Kaarlo Cajander. (1922). Zur Begriffsbestimmung im Gebiet der Pflanzentopographie. Acta Forestalia Fennica vol. 20 no. 2 article id 7062. https://doi.org/10.14214/aff.7062
English title: Determining concepts for topography of plants.

The article presents definitions for central concepts that are commonly used in the research of plant topography. The discipline has close connections to defining and classifying forest types.

The concepts defined involve concrete and abstract concepts linked to vegetation conditions and to habitat. 

  • Cajander, ORCID ID:E-mail:
article id 5265, category Article
J. Ross, S. Kellomäki, P. Oker-Blom, V. Ross, L. Vilikainen. (1986). Architecture of Scots pine crown. Silva Fennica vol. 20 no. 2 article id 5265. https://doi.org/10.14214/sf.a15444

Dimensions (length, width and thickness) of needles in crowns of young Scots pine (Pinus sylvestris L.) were found to be related linearly to each other. Similarly, the needle area was linearly correlated with the needle biomass. In the lower crown, needle length was linearly correlated with the length of the shoot, but in the upper crown needle length did not vary according to any regular pattern. Needle density was negatively correlated with shoot length. In the lower crown the needle density varied 20–40 cm-1 and in the upper crown 15– 20 cm-1. The increasing angle of aging needles seemed to be characteristic for Scots pine shoots.

The PDF includes an abstract in Finnish.

  • Ross, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
  • Oker-Blom, ORCID ID:E-mail:
  • Ross, ORCID ID:E-mail:
  • Vilikainen, ORCID ID:E-mail:
article id 5257, category Article
Heikki Hänninen. (1986). Metsäpuiden vuosirytmitutkimuksen käsitteistä ja teorioista. Silva Fennica vol. 20 no. 1 article id 5257. https://doi.org/10.14214/sf.a15436
English title: Conceptual remarks about the study of the annual rhythm of forest trees.

Different approaches to the study of the annual rhythm of forest trees are described and compared by analysing the concepts and theories presented in the literature. The seasonality varying morphological and physiological state of forest trees is referred to as the annual rhythm s. lat., from which the annual ontogenetic rhythm is separated as a distinct type. The dormancy phenomena of the trees are grouped into four categories. Theories concerning the regulation of the annual rhythm are divided into two main types, the most common examples of which are the photoperiod theory and the temperature sum theory. Recent efforts towards a synthetic theory are described.

The PDF includes a summary in English.

  • Hänninen, ORCID ID:E-mail:
article id 5257, category Article
Heikki Hänninen. (1986). Metsäpuiden vuosirytmitutkimuksen käsitteistä ja teorioista. Silva Fennica vol. 20 no. 1 article id 5257. https://doi.org/10.14214/sf.a15436
English title: Conceptual remarks about the study of the annual rhythm of forest trees.

Different approaches to the study of the annual rhythm of forest trees are described and compared by analysing the concepts and theories presented in the literature. The seasonality varying morphological and physiological state of forest trees is referred to as the annual rhythm s. lat., from which the annual ontogenetic rhythm is separated as a distinct type. The dormancy phenomena of the trees are grouped into four categories. Theories concerning the regulation of the annual rhythm are divided into two main types, the most common examples of which are the photoperiod theory and the temperature sum theory. Recent efforts towards a synthetic theory are described.

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  • Hänninen, ORCID ID:E-mail:
article id 5256, category Article
Outi Muona, Raimo Hiltunen, Erkki Morén, D. V. Shaw. (1986). Analysis of monoterpene variation in natural stands and plustrees of Pinus sylvestris in Finland. Silva Fennica vol. 20 no. 1 article id 5256. https://doi.org/10.14214/sf.a15435

Variation of monoterpene composition of Pinus sylvestris L. was studied in Southern, Central and Northern Finland using data from both natural stands and plus trees. The natural stands were analysed using different techniques and for fewer terpenes than the plus trees.

There were large differences between areas in the proportion of 3-carene in trees from natural stands, as has been discussed by previous authors. The proportion of 3-carene is bimodally distributed and believed to be controlled by a single gene with large effect. For this reason, we stratified our samples into high carene (>10%) and low carene (<10%) groups. Univariate analysis did not reveal any additional differences between natural populations in different zones for components other than 3-carene. In plus trees, several components showed significant differences, but the proportion of 3-carene did not differ between areas. Multivariate discrimination analysis did not distinguish between areas for natural stands. However, for the plus trees discriminant analysis allowed us to discriminate between the zones relatively efficiently. The proportion of correct classification was greater than 64% using the best methods. The central zone was most distinct, and 80% of its trees were correctly classified. Broad generalizations are not possible due to the limitations imposed by our data. Our analysis of phenotypic variation does not support the suggestion that plus trees selected from the north represent a southern type.

The PDF includes an abstract in Finnish.

  • Muona, ORCID ID:E-mail:
  • Hiltunen, ORCID ID:E-mail:
  • Morén, ORCID ID:E-mail:
  • Shaw, ORCID ID:E-mail:
article id 5240, category Article
Pertti Harstela, Kimmo Piirainen. (1985). Effect of whole-body vibration and driving a forest machine simulator on some physiological variables of the operator. Silva Fennica vol. 19 no. 2 article id 5240. https://doi.org/10.14214/sf.a15419

The influence of horizontal whole-body vibration of fairly low intensity alone and combined with the mental load and motor action typical for the forest machine drive on heart rate variability (HRV), respiration rate (RR) and heart rate (HR) was studied by testing five subjects. Horizontal vibration had an influence on HR, HRV and RR. ’Control activities’ had the most influence on RR and HRV, but some influence on HR, too. ’Moving the control devices’ (motor action) gave the same response in HR as ’control activities’, but not in HRV and RR. ’Control activities’ together with ’vibration’ had a more effect on HRV and RR than these two factors singly, but not on HR. The possibilities of using these variables in field studies are discussed.

The PDF includes a summary in Finnish.

  • Harstela, ORCID ID:E-mail:
  • Piirainen, ORCID ID:E-mail:
article id 5234, category Article
Eino Mälkönen, Eero Paavilainen. (1985). Hydrological amelioration and forest practice on drained peatlands. Silva Fennica vol. 19 no. 2 article id 5234. https://doi.org/10.14214/sf.a15413

This bibliography consists of monographs, papers published in periodicals and journals and collections of scientific papers from research and educational institutes, and transactions from scientific congresses, seminars, symposia and meetings.

The publications have been divided into three basic sections. In each section the publications are listed in alphabetical order by the author(s) or title. The total number of the titles in this bibliography is 465.

  • Mälkönen, ORCID ID:E-mail:
  • Paavilainen, ORCID ID:E-mail:
article id 5210, category Article
Heikki Smolander, Juha Lappi. (1984). The interactive effect of water stress and temperature on the CO2 response of photosynthesis in Salix. Silva Fennica vol. 18 no. 2 article id 5210. https://doi.org/10.14214/sf.a15389

The interactive effects of water stress and temperature on the CO2 response of photosynthesis was studied in Salix sp. cv. Aquatica using the closed IRGA system. A semi-empirical model was used to describe the CO2 response of photosynthesis. The interactive effect of water stress and temperature was divided into two components: the change in CO2 conductance and the change in the photosynthetic capacity. The CO2 conductance was not dependent on the temperature when the willow plant was well watered, but during water stress it decreased as the temperature increased. The photosynthetic capacity of the willow plant increased along with an increase in temperature when well-watered, but during water stress temperature had quite opposite effect.

The PDF includes a summary in Finnish.

  • Smolander, ORCID ID:E-mail:
  • Lappi, ORCID ID:E-mail:
article id 5202, category Article
Kari Löyttyniemi. (1983). Flight periods of some birch timber insects. Silva Fennica vol. 17 no. 4 article id 5202. https://doi.org/10.14214/sf.a15185

Flight periods of insects breeding on birch (Betula sp.) timber were observed by means of window flight traps baited with freshly cut birch logs in five locations in Finland from 1972 to 1976. Only few species were caught during the study. In general, these species were on the wing during midsummer, although flight periods of some of them were relatively long. Scolytus ratzeburgi Jans. caused harmful staining of wood within a month from attack, but the damage by the wood-boring pests remained negligible throughout the first storage summer.

The PDF includes a summary in Finnish.

  • Löyttyniemi, ORCID ID:E-mail:
article id 5193, category Article
Juhani Jokinen, Antti Häkkinen, Reijo Karjalainen, Kari Markkanen, Tapani Säynätkari. (1983). Effects of air pollution on Scots pine needles. I. Silva Fennica vol. 17 no. 3 article id 5193. https://doi.org/10.14214/sf.a15176

The effect of meteorological factors, the total sulphur content of the needles, and SO2 concentration in the ambient air on total peroxidase activity of Scots pine (Pinus sylvestris L.) needles was investigated in material obtained from Southern Finland. The correlation between temperature and total peroxidase activity was highest during the most active growing period. Linear correlation between relative humidity and total peroxidase activity appears to be low. The correlation between atmospheric SO2 concentration and total peroxidase activity was also low and varied inconsistently. The detected low association between the sulphur dioxide pollutant and the total peroxidase activity was assumed to be related to the sensitivity of peroxidase activity, many eco-physiological factors and to the genetic variation in conifers. It is difficult to separate a response due to this pollutant from environmental and genetic factors in a complex coniferous forest. Using total peroxidase activity as a routine indicator of air pollution seems to be unsuitable because of the large sample size required in order to obtain a reliable measurement of the pollutant’s effect under low pollution levels.

The PDF includes a summary in Finnish.

  • Jokinen, ORCID ID:E-mail:
  • Häkkinen, ORCID ID:E-mail:
  • Karjalainen, ORCID ID:E-mail:
  • Markkanen, ORCID ID:E-mail:
  • Säynätkari, ORCID ID:E-mail:
article id 5184, category Article
Annikki Karjalainen, Lauri Hyväkkä, Sini Kärki-Folkersma. (1983). Metsätieteellisen kirjallisuuden haku atk-tiedostoista. Silva Fennica vol. 17 no. 2 article id 5184. https://doi.org/10.14214/sf.a15100
English title: Experiences of some bibliographic databases in forestry.

The usefulness of some international bibliographic databases for Finnish forest researchers was studied. In this study, 26 gratis online searches from one or more databases was made. The searches were carried out using mainly AGRICOLA, BIOSIS and CAB databases. The most used database was CAB, which includes Forestry Abstracts. The relevance of the references retrieved was evaluated by the users. Recall, precision, novelty and overlap of the references were measured. The users evaluated the results and costs of their search. Some previous comparable studies are reviewed.

The PDF includes a summary in English.

  • Karjalainen, ORCID ID:E-mail:
  • Hyväkkä, ORCID ID:E-mail:
  • Kärki-Folkersma, ORCID ID:E-mail:
article id 5169, category Article
Seppo Kellomäki, Pasi Puttonen, Heikki Tamminen, Carl Johan Westman. (1982). Effect of nitrogen fertilization on photosynthesis and growth in young Scots pines. Preliminary results. Silva Fennica vol. 16 no. 4 article id 5169. https://doi.org/10.14214/sf.a15084

Application of nitrogen at levels of 200, 400 and 600 kg ha-1 resulted in increases of 35, 18 and 12% in the photosynthetic rate in young Scots pine (Pinus sylvestris L.). The number of buds, degree of branching, and needle size were positively related to the amount of nitrogen applied. A 10–40% increase in the average needle area was found. A positive correlation was found between total photosynthesis and stem growth.

The PDF includes a summary in Finnish.

  • Kellomäki, ORCID ID:E-mail:
  • Puttonen, ORCID ID:E-mail:
  • Tamminen, ORCID ID:E-mail:
  • Westman, ORCID ID:E-mail:
article id 5164, category Article
Juhani Kangas, Tapio Klen. (1982). Raivaussahan kantokäsittelylaitteen käyttäjän altistuminen torjunta-aineille. Silva Fennica vol. 16 no. 3 article id 5164. https://doi.org/10.14214/sf.a15079
English title: Exposure of forest workers to herbicides.

The purpose of this study was to measure workers’ exposure to MCPA and glyphosate when sprayers connected to the brush saws was used. A non-pressurized sprayer with a pump and a pressurized sprayer where dosage was regulated with manual control were studied. Exposure was measured from the breathing zone and urine samples.

MCPA collected from the breathing zone gathered into alcohol was 0.05 mg/m3 for the pressurized sprayer, 0.02 mg/m3 for the non-pressurized sprayer, and 0.04 mg/m3 (average) for both types of sprayers together.

MCPA in the breathing zone, collected from splashes and fog into a glass fibre filter, was 0.18 mg/m3 for the pressurized sprayer, 0.09 mg/m3 for the non-pressurized sprayer, and 0.12 mg/m3 for both sprayers used together. Glyphosate in the breathing zone, collected into sodium hydroxide was below 0.05 mg/m3.

In five urine samples taken after the work day there was on the average 0.4 mg/l MCPA, while in 21 samples the MCPA contents were under the definition limit (0.2 mg/l).

The PDF includes a summary in Finnish.

  • Kangas, ORCID ID:E-mail:
  • Klen, ORCID ID:E-mail:
article id 5161, category Article
Juhani Päivänen. (1982). Physical properties of peat samples in relation to shrinkage upon drying. Silva Fennica vol. 16 no. 3 article id 5161. https://doi.org/10.14214/sf.a15076

The study discusses the amount of shrinkage of volumetric undisturbed peat samples when drying to an oven-dry (105°C) condition. The amount of shrinkage is related to various physical properties of peat. In addition, some observations were performed on the shrinkage phenomenon during the drying process. The study results may be used when predicting the shrinkage of peat samples with various peat properties. Knowledge of this kind is particularly important in connection with peat harvesting.

The PDF includes a summary in Finnish.

  • Päivänen, ORCID ID:E-mail:
article id 5154, category Article
Satu Huttunen, Sinikka Kallio, Marketta Karhu. (1981). The effect of air pollution on transplanted mosses. Silva Fennica vol. 15 no. 4 article id 5154. https://doi.org/10.14214/sf.a15381

The use of forest mosses as bioindicators was tested with transplanted experiments. One transplantation experiment was made to study effects of air pollutants on two forest moss species, Hylocomnium splendens (Hedw.) Schimp. and Pleurozium schreberi (Willd. ex Brid.) Mitt. Another transplantation was used to study the nitrogen fixation capacity of blue-green algae in the Hylocomnium and Pleurozium moss layers. The surface structure of the moss species was studied by scanning electron microscopy. The air pollution induced changes in the surface structure of moss cells were observable soon after the transplantation. In polluted industrial areas the fertilizing effect of air-borne nitrogen compounds increased the photosynthetic activity of mosses before their destruction. Stress respiration was also observable in polluted areas. The nitrogen fixing capacity decreased or was almost inhibited in all the air-polluted environments.

  • Huttunen, ORCID ID:E-mail:
  • Kallio, ORCID ID:E-mail:
  • Karhu, ORCID ID:E-mail:
article id 5153, category Article
T. Raunemaa, R. Erkinjuntti, M. Gerlander, A. Hautojärvi, K. Kaisla, H.-S. Katainen. (1981). Multielement analysis of treated pine seedlings. Silva Fennica vol. 15 no. 4 article id 5153. https://doi.org/10.14214/sf.a15380

A comparison study concerning the effects of acid rain on Scots pine (Pinus sylvestris L.) seedlings has been performed. Two different X-ray fluorescence methods, PIXE and IXRF, were employed to produce multielement analyses of the samples. Seedlings were treated for 3 months with watering of pH=7 or pH=3 liquids on the needles and on the roots. One year and two years old needles of the seedlings were inspected for changes in photosynthetic rate as well as for changes in elemental concentrations.

Twelve elements from Si to Zn were compared in the samples. The PIXE results show that the amounts of most of these elements in the needles of the seedlings grown in sand increase, when treated with acid water. This growth is clearer when the roots are treated with acid water. The elemental concentrations of the needles in the seedlings grown in soil on the other hand decrease slightly.

  • Raunemaa, ORCID ID:E-mail:
  • Erkinjuntti, ORCID ID:E-mail:
  • Gerlander, ORCID ID:E-mail:
  • Hautojärvi, ORCID ID:E-mail:
  • Kaisla, ORCID ID:E-mail:
  • Katainen, ORCID ID:E-mail:
article id 5151, category Article
A. Mäkelä, P. Hari, Seppo Kellomäki. (1981). A model for the effect of air pollutants on forest growth. Silva Fennica vol. 15 no. 4 article id 5151. https://doi.org/10.14214/sf.a15378

A model was constructed, the aim of which was to predict growth under conditions where air pollutants are present. The model is based on photosynthesis and on the allocation of photosynthetic products for growth. It is assumed that air pollutants released during energy production mainly affect photosynthesis in two ways: 1) directly by injuring the photosynthetic mechanism, and 2) indirectly by leaching nutrients. The two ways were studied empirically in order to identify a sub-model for the photosynthesis of a plant exposed to air pollutants. 

The stand model will be applied to two purposes. The present stage of forests in Finland is compared with the simulated state based on the assumption that no pollutants are present. In addition, the decrease in forest yield under different conditions derived from predictions about long-range pollutant transport in Europe is analysed.

  • Mäkelä, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5151, category Article
A. Mäkelä, P. Hari, Seppo Kellomäki. (1981). A model for the effect of air pollutants on forest growth. Silva Fennica vol. 15 no. 4 article id 5151. https://doi.org/10.14214/sf.a15378

A model was constructed, the aim of which was to predict growth under conditions where air pollutants are present. The model is based on photosynthesis and on the allocation of photosynthetic products for growth. It is assumed that air pollutants released during energy production mainly affect photosynthesis in two ways: 1) directly by injuring the photosynthetic mechanism, and 2) indirectly by leaching nutrients. The two ways were studied empirically in order to identify a sub-model for the photosynthesis of a plant exposed to air pollutants. 

The stand model will be applied to two purposes. The present stage of forests in Finland is compared with the simulated state based on the assumption that no pollutants are present. In addition, the decrease in forest yield under different conditions derived from predictions about long-range pollutant transport in Europe is analysed.

  • Mäkelä, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5149, category Article
Toini Holopainen. (1981). Alterations in the ultrastructure of epiphytic lichens Hypogymnia physodes and Alectoria capillaris caused by air pollution. Silva Fennica vol. 15 no. 4 article id 5149. https://doi.org/10.14214/sf.a15376

The ultrastructure of Hypogymnia physodes (L.) Nyl. and Alectoria capillaris (Bryoria capillaris (Ach.) Brodo & D. Hawksw.) grown or transplanted near a fertilizer plant and a pulp mill was compared to normal ultrastructure of these lichen species. The ultrastructural changes observed were highly similar in the symbionts of both species and near both the factories although the emissions are different. In the lichens grown near the factories the number of algae had clearly increased. The appearance of the chloroplasts was roundish compared to controls. The pyrenoglobuli and cytoplasmic storage bodies were smaller than normally and the number of polyphosphate bodies had increased. Also, in mycobionts storage droplets were very small or absent and many vacuoles and dark inclusions appeared to hyphae in contrast to controls. In transplanted lichen there existed mainly the same ultrastructural changes as in the lichen grown near factories. Near the fertilizer plant the damage was, however, more severe because all the lichens died during 6–7 months after transplantation. Near the pulp mill part of the lichens survived and seemed to adapt to air pollution.

  • Holopainen, ORCID ID:E-mail:
article id 5148, category Article
A. Hautojärvi, S. Ahonen, R. Erkinjuntti, H.-S. Katainen, T. Lappalainen, T. Raunemaa. (1981). Surface concentration of sulphur on Scots pine needles. Silva Fennica vol. 15 no. 4 article id 5148. https://doi.org/10.14214/sf.a15375

A method to determine sulphur as sulphate has been applied to search for surface concentration of sulphate sulphur on needle samples. The method is based on reducing sulphates as volatile hydrogen sulphide gas by using hydriodic acid. The hydrogen sulphide gas is swept with nitrogen into an absorbent solution. Sulphide ion concentration in solution is then measured using ion selective electrodes.

The method was applied on one to four years old needle samples collected from Scots pine (Pinus sylvestris L.) at 0.9 to 15.9 km distances from a 1,064 MW coal-fired power plant in Southern Finland. Surface sulphate values found in the samples closer than 4 km to the power plant were 50 to 100% higher than a nearly constant background level. No significant variation of values with needle age was found. The advantages of the method compares to other methods for sulphur determination are speed, reasonable sensitivity and low detection limit.

  • Hautojärvi, ORCID ID:E-mail:
  • Ahonen, ORCID ID:E-mail:
  • Erkinjuntti, ORCID ID:E-mail:
  • Katainen, ORCID ID:E-mail:
  • Lappalainen, ORCID ID:E-mail:
  • Raunemaa, ORCID ID:E-mail:
article id 5148, category Article
A. Hautojärvi, S. Ahonen, R. Erkinjuntti, H.-S. Katainen, T. Lappalainen, T. Raunemaa. (1981). Surface concentration of sulphur on Scots pine needles. Silva Fennica vol. 15 no. 4 article id 5148. https://doi.org/10.14214/sf.a15375

A method to determine sulphur as sulphate has been applied to search for surface concentration of sulphate sulphur on needle samples. The method is based on reducing sulphates as volatile hydrogen sulphide gas by using hydriodic acid. The hydrogen sulphide gas is swept with nitrogen into an absorbent solution. Sulphide ion concentration in solution is then measured using ion selective electrodes.

The method was applied on one to four years old needle samples collected from Scots pine (Pinus sylvestris L.) at 0.9 to 15.9 km distances from a 1,064 MW coal-fired power plant in Southern Finland. Surface sulphate values found in the samples closer than 4 km to the power plant were 50 to 100% higher than a nearly constant background level. No significant variation of values with needle age was found. The advantages of the method compares to other methods for sulphur determination are speed, reasonable sensitivity and low detection limit.

  • Hautojärvi, ORCID ID:E-mail:
  • Ahonen, ORCID ID:E-mail:
  • Erkinjuntti, ORCID ID:E-mail:
  • Katainen, ORCID ID:E-mail:
  • Lappalainen, ORCID ID:E-mail:
  • Raunemaa, ORCID ID:E-mail:
article id 5146, category Article
J. N. Cape, D. Fowler. (1981). Changes in epicuticular wax of Pinus sylvestris exposed to polluted air. Silva Fennica vol. 15 no. 4 article id 5146. https://doi.org/10.14214/sf.a15373

Scanning Electron Microscopy was used to study structural changes in epicuticular vax of Pinus sylvestris L. with time. Changes in the contact angle of water droplets and in cuticular transpiration were also measured. By using material from a polluted and an unpolluted site it was shown that the ageing process occurs faster on polluted air, leading to greater cuticular transpiration and smaller contact angles at polluted sites.

  • Cape, ORCID ID:E-mail:
  • Fowler, ORCID ID:E-mail:
article id 5144, category Article
Lennart Folkeson. (1981). Impact of air-borne copper and zinc pollution on lichen and bryophyte vegetation near a brass foundry. Silva Fennica vol. 15 no. 4 article id 5144. https://doi.org/10.14214/sf.a15371

Air-borne Cu and Zn from a brass foundry at Gusum, SE Sweden, have considerably disturbed the lichen and bryophyte vegetation in the coniferous forest environment. The occurrence of lichens on Norway spruce twigs decreased rapidly with increasing Cu concentrations in Hypogymnia physodes above 90 ppm (background value 10–15). The epiphytic vegetation is reduced within 2–3 km from the foundry. Only stunted individuals occur in the close vicinity of the pollution source.

The cover of one of the quantitatively most important mosses, Hylocomnium splendens, is greatly reduced by the heavy-metal deposition. Cover values of 20–50% are not uncommon in distant sites (Cu concentration 15–35 ppm). There is a significant negative correlation between Cu concentration in the moss and its cover. The moss cannot survive much more than ca. 130 ppm Cu (and 360 ppm Zn). Live individuals are no more found within 1.5 km from the foundry.

  • Folkeson, ORCID ID:E-mail:
article id 5144, category Article
Lennart Folkeson. (1981). Impact of air-borne copper and zinc pollution on lichen and bryophyte vegetation near a brass foundry. Silva Fennica vol. 15 no. 4 article id 5144. https://doi.org/10.14214/sf.a15371

Air-borne Cu and Zn from a brass foundry at Gusum, SE Sweden, have considerably disturbed the lichen and bryophyte vegetation in the coniferous forest environment. The occurrence of lichens on Norway spruce twigs decreased rapidly with increasing Cu concentrations in Hypogymnia physodes above 90 ppm (background value 10–15). The epiphytic vegetation is reduced within 2–3 km from the foundry. Only stunted individuals occur in the close vicinity of the pollution source.

The cover of one of the quantitatively most important mosses, Hylocomnium splendens, is greatly reduced by the heavy-metal deposition. Cover values of 20–50% are not uncommon in distant sites (Cu concentration 15–35 ppm). There is a significant negative correlation between Cu concentration in the moss and its cover. The moss cannot survive much more than ca. 130 ppm Cu (and 360 ppm Zn). Live individuals are no more found within 1.5 km from the foundry.

  • Folkeson, ORCID ID:E-mail:
article id 5142, category Article
Lars Moseholm. (1981). Responses of transplanted lichens to sulphur dioxide dosages - a new semi-statistical dosage/injury model. Silva Fennica vol. 15 no. 4 article id 5142. https://doi.org/10.14214/sf.a15369

A semi-statistical model is suggested for monitoring injuries of plants for long-time field exposures (months). The model is based on the following assumptions:

1. The concentrations of air pollutants in the atmosphere follow the Johnson SB distribution.

2. The degree of plant injury is proportional to the logarithm of air pollutant dose.

3. No injuries occur below a certain dose level.

4. A dose is defined as the air pollutant concentration multiplied by the duration of exposure raised to an exponent.

Based on the air pollutant frequency distribution a total dose for the exposure period is calculated by integration, and the total dose is related to the observed plant injury by non-linear regression. The model is tested for long-time exposures of sulphur dioxide to transplant lichen in natural environment.

  • Moseholm, ORCID ID:E-mail:
article id 5141, category Article
Lisbeth Mortensen, Knud V. Weisberg. (1981). A method for measurement of actue leaf injury on tobacco indicator plants. Silva Fennica vol. 15 no. 4 article id 5141. https://doi.org/10.14214/sf.a15368

A technique for instrumental scoring of damaged leaves on tobacco (Nicotiana tabacum) indicator plants caused by ozone in the lower atmosphere is being developed. The leaves are photographed in situ with an integrated unit, which illuminates the leaf from behind and keeps the camera in a well-defined position. By using microfilm and a minus green filter, it is possible to obtain negatives where the necrotic flecks appear as dark spots on a white leaf. The negatives are scanned in a TV-system and the size of the damaged fraction of the leaf is calculated by a microprosessor and is shown as a percentage of the leaf.

  • Mortensen, ORCID ID:E-mail:
  • Weisberg, ORCID ID:E-mail:
article id 5140, category Article
Lars Westman. (1981). Monitoring of coniferous forest ecosystems in Sweden. Silva Fennica vol. 15 no. 4 article id 5140. https://doi.org/10.14214/sf.a15367

A monitoring program is planned for the terrestrial environment around industries in Sweden, which emit acid compounds and heavy metals. Directions for the County Government Boards are being prepared. The paper deals with the present pollution situation in Sweden, based on recent scientific results, the justifications for local monitoring, and the organizing of the monitoring including the parameters suggested.

Four examples from a case study at an oil power station illustrate reporting of the data and the difficulties in interpreting the results. The examples are the distribution of a lichen indicator, heavy metal content and phosphatase activity in the moor layer, soil respiration and tree growth.

  • Westman, ORCID ID:E-mail:
article id 5139, category Article
Boguslaw Molski, Andrzej Bytnerowicz, Wojciech Dmuchowski. (1981). Content of sulphur and fluorine compounds in Scots pine needles as an indicator of air pollution in Poland. Silva Fennica vol. 15 no. 4 article id 5139. https://doi.org/10.14214/sf.a15366

Our preliminary findings indicate that the content of total sulphur and soluble fluorides in needles of the Scots pine (Pinus sylvestris L.) reflects the degree of air pollution with sulphur and fluorine compounds. A project for a map of air pollution in Poland, based on chemical analysis of Scots pine needles, is presented. Results of the total sulphur and soluble fluoride content in 2-year old needles from 15- to 25-year-old trees should yield a picture of air pollution with sulphur and fluorine compounds. The first stage will involve the preparation of a map of the area between the Warsaw and Plock agglomerations. This area will be divided into 10 squares with side dimension of 25 km each. Samples will be taken at 5 different sites in each square and also approximately every 5 km along a straight line between these towns.

  • Molski, ORCID ID:E-mail:
  • Bytnerowicz, ORCID ID:E-mail:
  • Dmuchowski, ORCID ID:E-mail:
article id 5138, category Article
K. Kvist, C. Jakobsson. (1981). Vegetation injury occurring after winter at a fertilizer factory. Silva Fennica vol. 15 no. 4 article id 5138. https://doi.org/10.14214/sf.a15365

Air pollution injury to vegetation often occurs near a fertilizer factory in Central Sweden. The causing incidence often occurs in the winter and the symptoms appear when metabolism starts in the spring. Deciduous and coniferous trees and bushes were injured in the spring of 1979. Samples of Scots pine (Pinus sylvestris L.) needles were analysed for sulphur, total fluorine and nitrogen content, some of them for nitrate and ammonium. All the compounds showed elevated levels, clearly connected with the degree of exposure of the sampling site. The levels were higher in the spring than later in the growing season, indicating involvement in metabolism or leaching. None of the compounds was significantly in excess, although, elevated to an extent to indicate the cause of injury. Most probably the nitrogen compounds were involved. The problems encountered in tracing the causing pollutant, when injury appeared long after the incidence, might be easier solved with regularly used technical monitoring and bioindicator technique.

  • Kvist, ORCID ID:E-mail:
  • Jakobsson, ORCID ID:E-mail:
article id 5137, category Article
V. C. Runeckles, K. T. Palmer, H. Trabelsi. (1981). Effects of field exposures to SO2 on Douglas fir, Agropyron spicatum and Lolium perenne. Silva Fennica vol. 15 no. 4 article id 5137. https://doi.org/10.14214/sf.a15364

Grasses Agropyron spicatum Pursh, Lolium perenne L. (S23) and 2-year old Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) were exposed to low SO2 concentrations under field conditions for approximately eleven weeks. SO2 was released continuously via manifold delivery systems, and provided treatment mean concentrations of 0.007 (ambient air), 0.042, 0.106 and 0.198 ppm. The concentrations in each treatment were approximately log-normally distributed, with standard geometric deviations ranging from 2.58 to 3.24. In both grass species, 0.198 ppm SO2 caused substantial reduction of total growth. In L. perenne, this was largely the result of impaired root growth, whereas both shoot and root growth of A. spicatum were reduced. 0.106 ppm SO2 had no significant effect on A. spicatum growth, but reduced root growth of L. perenne. Growth of Douglas fir was reduced in each of the tree highest concentrations, with root growth being markedly diminished, particularly on trees which showed chlorotic and necrotic injury. However, in these trees the shoot and total leaf weights tended to increase at the highest SO2 concentrations, suggesting that in these plants injury to leaves stimulated further shoot growth at the expense of root development.

  • Runeckles, ORCID ID:E-mail:
  • Palmer, ORCID ID:E-mail:
  • Trabelsi, ORCID ID:E-mail:
article id 5136, category Article
Sirkka Soikkeli. (1981). The types of ultrastructural injuries in conifer needles of northern industrial environments. Silva Fennica vol. 15 no. 4 article id 5136. https://doi.org/10.14214/sf.a15363

Ultrastructure of mesophyll of second-year green needles of Picea abies (L.) H. Karst. and Pinus sylvestris (L.) has been studied in several polluted areas in Finland since 1976 (Soikkeli and Tuovinen 1979, Soikkeli 1981a). Four different types of injuries have been found. The types differ with the origin of the material:

1) In needles collected from areas pollute by S-communds the types with reduced grana and/or the with lightening of plastogobuli with simultaneous accumulation of lipid-like material are observed.

2) In needles expose to fluorides (alone or in addition to other pollutants) the type with swollen and/or that with curled thylakoids are found. Both of the latter have also stretched envelopes. In each type of the injury three stages of cell disruption have been described: slight-medium, severe and very severe. On the slight-medium stage the injuries are usually found only in chloroplasts. On severe stage other organelles show injuries, too. In very severe injury all cell organelles are badly disorganized or they disappear completely. The most abundant injuries are usually in needles collected after their second winter. The severity of cell injury depends on the closeness of emission source or on the measured concentration of SO2.

  • Soikkeli, ORCID ID:E-mail:
article id 5135, category Article
L. Skärby, C. Bengtson, C.-Å. Boström, P. Grennfelt, E. Troeng. (1981). Uptake of NOx in Scots pine. Silva Fennica vol. 15 no. 4 article id 5135. https://doi.org/10.14214/sf.a15362

Information on input of acidifying compounds like SO2 and NOx is necessary to understand effects of acidification. The uptake on NO and NO2 respectively was studied on seedlings and shoots of Scots pine (Pinus sylvestris L.). Experiments were conducted both in laboratory (NO and NO2 respectively) and in the field (NO2) under light and dark conditions. In all three cases there was a linear relationship between the uptake rate and the NOx-concentration. The uptake follows a diurnal pattern i.e. the uptake rate was strongly correlated with the stomatal movements. Uptake rates were converted to deposition rate and the results showed that field exposure with NO2 gave the higher deposition rate.

  • Skärby, ORCID ID:E-mail:
  • Bengtson, ORCID ID:E-mail:
  • Boström, ORCID ID:E-mail:
  • Grennfelt, ORCID ID:E-mail:
  • Troeng, ORCID ID:E-mail:
article id 5131, category Article
Risto Jalkanen, Satu Huttunen, Teija Väisänen. (1981). The wax structure of the developing needles of Pinus sylvestris progenies infected by Lophodermella sulcigena. Silva Fennica vol. 15 no. 4 article id 5131. https://doi.org/10.14214/sf.a15188

The development of the stomatal area wax structure of Scots pine (Pinus sylvestris L.) needles was studied in flushing needles with a scanning electron microscope. The needles were obtained from eleven Finnish plus tree progenies. The needles were taken from trees that were either nearly uninfected or heavily infected by Lophodermella sulcigena (Rostr.) Höhn.

No difference in the early developmental stages of stomatal vax structure were observed between the southern Finnish, central Finnish and northern Finnish progenies. The general structure differed in the stomatal cavity chamber size. The stomatal openings were larger in heavily infected trees than in healthy trees. This might have an influence on the mechanical penetration of the fungal hyphae.

The PDF includes a summary in Finnish.

  • Jalkanen, ORCID ID:E-mail:
  • Huttunen, ORCID ID:E-mail:
  • Väisänen, ORCID ID:E-mail:
article id 5125, category Article
Ilppo Greis, Seppo Kellomäki. (1981). Crown structure and stem growth of Norway spruce undergrowth under varying shading. Silva Fennica vol. 15 no. 3 article id 5125. https://doi.org/10.14214/sf.a15066

The crown structure and stem growth of Norway spruce (Picea abies (L.) H. Karst.) undergrowth was studied in relation to the prevailing light conditions and potential photosynthesis. Shading decreased the stem height growth more than the length increment of laterals, producing a plate-shaped crown in deep shade. Needles responded to shading by adopting a horizontal inclination in deep shade. The needles were wide and thin respectively in shade. In the open the needle cross-section was almost square. Stem radial growth and height growth were both affected by shading exhibiting a linear response to the prevailing light conditions and the potential photosynthesis. Light conditions under dominating trees were closely correlated with the basal area of the dominating trees.

The PDF includes a summary in Finnish.

  • Greis, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5123, category Article
Heljä-Sisko Katainen, Seppo Kellomäki. (1981). Happaman veden vaikutus männyn taimiin. Silva Fennica vol. 15 no. 3 article id 5123. https://doi.org/10.14214/sf.a15064
English title: Effect of foliar application of dilute sulphuric acid on Scots pine seedlings.