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Silva Fennica vol. 53 no. 1 | 2019

Category: Editorial

article id 10164, category Editorial
Matti Maltamo. (2019). Silva Fennica in 2019. Silva Fennica vol. 53 no. 1 article id 10164. https://doi.org/10.14214/sf.10164
  • Maltamo, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail: matti.maltamo@uef.fi (email)

Category: Research article

article id 10076, category Research article
Tore Skrøppa, Arne Steffenrem. (2019). Genetic variation in phenology and growth among and within Norway spruce populations from two altitudinal transects in Mid-Norway. Silva Fennica vol. 53 no. 1 article id 10076. https://doi.org/10.14214/sf.10076
Highlights: Norway spruce populations distributed along each of two altitudinal transects showed strong clinal relationships between the annual mean temperatures of the sites of the populations and height and phenology traits in short term tests and height in field trials; Large variation was present among families within populations for height and phenology traits and with a wider range within than among populations; Correlation patterns among traits were different for provenances and families.

Progenies from open pollinated cones collected in natural populations of Norway spruce (Picea abies (L.) Karst.) distributed along two altitudinal transects in Mid-Norway were tested in the nursery, in short term tests and in long-term field trials. The populations showed clinal variation related to the mean annual temperatures of the populations, with the earliest bud flush and cessation of shoot elongation and lowest height at age nine years for the high altitude populations. Within population variation was considerable as the narrow sense heritability for these traits was 0.67, 0.31 and 0.09 in one transect and 0.55, 0.18 and 0.14 in the other transect, respectively. Lammas shoots occurred in the short term trials with large variation in frequency between years. There was significant family variation for this trait, but also interactions between populations and year. The variance within populations was considerably larger in the populations from low altitude compared to the high-altitude populations. Significant genetic correlations between height and phenology traits and damage scores indicate that families flushing early and ceasing growth late were taller. Taller families also had higher frequencies of damages. Selection of the top 20% families for height growth in short term tests at age nine years gave a simulated gain of 11% increased height growth at age 18 years in long term trials at altitudes similar to those of origin of the populations. The gain was negative when high altitude populations were selected based on testing in the lowland.

  • Skrøppa, Norwegian Institute of Bioeconomy Research, P.O. Box 115, 1431 Ås, Norway ORCID ID:E-mail: tore.skroppa@nibio.no (email)
  • Steffenrem, ORCID ID:E-mail:
article id 10062, category Research article
Jouni Siipilehto, Miika Rajala. (2019). Model for diameter distribution from assortments volumes: theoretical formulation and a case application with a sample of timber trade data for clear-cut sections. Silva Fennica vol. 53 no. 1 article id 10062. https://doi.org/10.14214/sf.10062
Highlights: The Weibull distribution was solved successfully from assortment volumes using optimization; The solved distribution provided accurate assortment volume when the input variables were correct; Goodness-of-fit tests indicate the compatibility between the solved distribution and the cut trees, according to harvester data; Timber trade contracts showed overestimated average merchantable tree sizes, which resulted in an underestimation of the number of cut trees; The reason for underestimation seemed to be in the decreasing distributions.

This study examined a theoretical model for stand structures from the volumes of pulpwood and saw logs of clear-cut stands. The average stem size was used to estimate the number of cut trees. The distribution was solved using nonlinear derivative-free optimization. The truncated 2-parameter Weibull distribution was used to describe the stand structure of the commercial stems. This method was first tested with harvester data collected from seven clear-cut stands in southern Finland. Validation included reliability in the stand characteristics and goodness-of-fit of the species-specific distributions. The distributions provided unbiased estimates for the saw log volume, while the bias in the estimated pulpwood volume was 2%. The standard stand characteristics from the Weibull distributions corresponded notably well with the harvester data. A Kolmogorov-Smirnov (KS) test rejected two distributions out of 21 cases, when the accurate input variables were available for the theoretical model. The results of the study suggest that the presented method is a relevant option for predicting the stand structure. In practice, the reliability of the presented method was dependent on the quality of the information available from the stand prior to cutting. With a timber trade data set, the solution for the distribution for a clear-cut section was found. The goodness-of-fit was dependent on the accuracy of the visually assessed timber trade variables. Especially the average stem size proved difficult to assess due to high number of understorey pulpwood stems. Due to overestimated average stem sizes, the solved number of harvested trees was underestimated. Less than 50% of the distributions predicted for clear-cut sections passed the KS test.

  • Siipilehto, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, P.O. Box 2, FI-00790 Helsinki, Finland ORCID ID:E-mail: jouni.siipilehto@luke.fi (email)
  • Rajala, Metsä Group, Revontulenpuisto 2, P.O. Box 10, 02020 METSÄ, FI-02100 Espoo, Finland ORCID ID:E-mail: miika.rajala@metsagroup.com
article id 10052, category Research article
Pentti Niemistö, Harri Kilpeläinen, Henrik Heräjärvi. (2019). Effect of pruning season and tool on knot occlusion and stem discolouration in Betula pendula – situation five years after pruning. Silva Fennica vol. 53 no. 1 article id 10052. https://doi.org/10.14214/sf.10052
Highlights: The occlusion was the fastest in the case of small living branches of fast growing trees pruned in springtime; Occlusion was quicker after saw pruning than after secateurs pruning, due to shorter knot stubs; Branches that were pruned in living state occluded faster than the ones pruned as dead; Dead branches hit down with a stick occluded slowly.

This paper investigates and models the effects of pruning season and tool on wound occlusion with varying tree and branch characteristics of silver birch (Betula pendula Roth) stems at the pruning height of 0−4 metres. Dates of eight secateurs prunings, three saw prunings and two sticks prunings as well as unpruned control were tested in permanent plots on four sites. Knot occlusion and discolouration in stemwood were measured from about 1600 studied knots of 112 sample trees felled five to six years after pruning in 2010. Knot occlusion rate was modelled according to pruning tool, date, tree growth, and branch characteristics. The occlusion was the fastest in trees pruned in spring or early summer, and the slowest in trees pruned in autumn. Stubs of living branches occluded faster than the dead ones with the same diameter. Saw pruning resulted in clearly better occlusion rates than secateurs pruning, caused by the shorter knot stubs after saw pruning. Hitting dead branches away with a stick resulted in the worst occlusion status. The colour defects spread more often upward from the knot than downward. Discolouration in stemwood was detected more frequently near to the pruned branches than the unpruned ones, and more widely near to the stubs of dead branches than the living ones. Most saw and secateurs pruned branches were completely occluded during the experiment, so these prunings were suitable for all branches under 20 mm in diameter, and for living branches even up to 30 mm in fast-growing trees.

  • Niemistö, Natural Resources Institute Finland (Luke), Natural resources, Kampusranta 9 C, FI-60320 Seinäjoki, Finland ORCID ID:E-mail: pentti.niemisto@luke.fi (email)
  • Kilpeläinen, Natural Resources Institute Finland (Luke), Production systems, Yliopistokatu 6 B, FI-80100 Joensuu, Finland ORCID ID:E-mail: harri.kilpelainen@luke.fi
  • Heräjärvi, Natural Resources Institute Finland (Luke), Production systems, Yliopistokatu 6 B, FI-80100 Joensuu, Finland ORCID ID:E-mail: henrik.herajarvi@luke.fi
article id 10050, category Research article
Jori Uusitalo, Jari Ala-Ilomäki, Harri Lindeman, Jenny Toivio, Matti Siren. (2019). Modelling soil moisture – soil strength relationship of fine-grained upland forest soils. Silva Fennica vol. 53 no. 1 article id 10050. https://doi.org/10.14214/sf.10050
Highlights: Penetration resistance (PR) is best predicted with moisture content (MC), bulk density and clay content; In fully saturated silty or clayey soils PR range from 600 to 800 kPa; The models can be linked with mobility models predicting rutting of forest machines.

The strength of soil is known to be dependent on water content but the relationship is strongly affected by the type of soil. Accurate moisture content – soil strength models will provide forest managers with the improved ability to reduce soil disturbances and increase annual forest machine utilization rates. The aim of this study was to examine soil strength and how it is connected to the physical properties of fine-grained forest soils; and develop models that could be applied in practical forestry to make predictions on rutting induced by forest machines. Field studies were conducted on two separate forests in Southern Finland. The data consisted of parallel measurements of dry soil bulk density (BD), volumetric water content (VWC) and penetration resistance (PR). The model performance was logical, and the results were in harmony with earlier findings. The accuracy of the models created was tested with independent data. The models may be regarded rather trustworthy, since no significant bias was found. Mean absolute error of roughly 20% was found which may be regarded as acceptable taken into account the character of the penetrometer tool. The models can be linked with mobility models predicting either risks of rutting, compaction or rolling resistance.

  • Uusitalo, Natural Resources Institute Finland (Luke), Production systems, Korkeakoulunkatu 7, FI-33720 Tampere, Finland ORCID ID:E-mail: jori.uusitalo@luke.fi (email)
  • Ala-Ilomäki, Natural Resources Institute Finland (Luke), Production systems Maarintie 6, FI-02150 Espoo, Finland ORCID ID:E-mail: jari.ala-ilomaki@luke.fi
  • Lindeman, Natural Resources Institute Finland (Luke), Production systems, Korkeakoulunkatu 7, FI-33720 Tampere, Finland ORCID ID:E-mail: harri.lindeman@luke.fi
  • Toivio, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: toiviojenny@gmail.com
  • Siren, Natural Resources Institute Finland (Luke), Production systems Maarintie 6, FI-02150 Espoo, Finland ORCID ID:E-mail: matti.siren@luke.fi
article id 10019, category Research article
Junyan Liu, Junfeng Tang, Si-Chong Chen, Wenbao Ma, Zheng Zheng, Tingfa Dong. (2019). Do tree cavity density and characteristics vary across topographical habitats in the tropics? A case study from Xishuangbanna, southwest China. Silva Fennica vol. 53 no. 1 article id 10019. https://doi.org/10.14214/sf.10019
Highlights: Cavities were significantly more abundant in high- and low-slope than high-plateau habitats; There are more “butt hollow” cavities in high-slope habitat and they occurred at a lower height; More “crack” cavities in low-slope habitat and they had a narrower entrance diameter; Certain types of cavities are concentrated in specific habitats, which provide opportunities for forest management and biodiversity conservation.

Despite the influence of cavities on the survival and distribution of cavity-dependent fauna, the variation in the density and characteristics of tree cavities across different habitat types in tropical forests is unknown. In this study, we surveyed 26 312 living trees from 376 species and compared cavity density and characteristics (height, size, type, and orientation) across five habitat types (valley, low-slope, high-slope, high-gully, and high-plateau) in a 20-hectare tropical rainforest in southwest China. From a total of 2047 cavities, we found that cavity density was mainly driven by habitat rather than tree species richness or diameter at breast height (DBH), and the characteristics of cavities were not uniformly distributed across habitats. Cavities were significantly more abundant in high- and low-slope than high-plateau habitats. Compared with other habitats, more “butt hollow” cavity types were found in high-slope habitat and they occurred at a lower tree height, whereas more “crack” cavities were found in low-slope habitat and they had a narrower entrance diameter. Although the mean orientation of cavities faced towards the northeast, cavity orientation varied significantly across habitat types. Our results indicate that certain types of cavities are concentrated in specific habitat types, which can provide avenues for forest management and biodiversity conservation. We highlight the importance of habitat heterogeneity in providing resources for cavity nesters.

  • Liu, Key Laboratory of Southwest China Wildlife Resources Conservation of Ministry of Education, Key Laboratory of Environmental Science and Biodiversity Conservation (Sichuan Province) and Institute of Plant Adaptation and Utilization in Southwest Mountains, China West Normal University, Nanchong, Sichuan 637009, China; Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China ORCID ID:E-mail: liujunyan2300@163.com
  • Tang, Key Laboratory of Southwest China Wildlife Resources Conservation of Ministry of Education, Key Laboratory of Environmental Science and Biodiversity Conservation (Sichuan Province) and Institute of Plant Adaptation and Utilization in Southwest Mountains, China West Normal University, Nanchong, Sichuan 637009, China ORCID ID:E-mail:
  • Chen, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex RH17 6TN, UK; Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Beer-Sheva 8499000, Israel ORCID ID:E-mail: chensichong0528@gmail.com
  • Ma, Ecological Restoration and Conservation of Forests and Wetlands Key Laboratory of Sichuan Province, Sichuan Academy of Forestry, Chengdu 610081, China ORCID ID:E-mail: mawenbao_2000@126.com
  • Zheng, Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China ORCID ID:E-mail: dioeco@outlook.com
  • Dong, Key Laboratory of Southwest China Wildlife Resources Conservation of Ministry of Education, Key Laboratory of Environmental Science and Biodiversity Conservation (Sichuan Province) and Institute of Plant Adaptation and Utilization in Southwest Mountains, China West Normal University, Nanchong, Sichuan 637009, China ORCID ID:E-mail: dongtf@aliyun.com (email)
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 9918, category Research article
Ari Nikula, Vesa Nivala, Juho Matala, Kari Heliövaara. (2019). Modelling the effect of habitat composition and roads on the occurrence and number of moose damage at multiple scales. Silva Fennica vol. 53 no. 1 article id 9918. https://doi.org/10.14214/sf.9918
Highlights: The occurrence and number of moose damage were modelled with a zero-inflated count model; An admixture of mature forests within plantations increased the number of damage; Vicinity of inhabited areas and roads reduced damage; Plantations in landscapes with a large amount of pine-dominated thinning forests had less damage in Lapland; Damage risk assessment should include characteristics specific to each region.

We modelled the effect of habitat composition and roads on the number and occurrence of moose (Alces alces L.) damage in Ostrobothnia and Lapland using a zero-inflated count model. Models were developed for 1 km2, 25 km2 and 100 km2 landscapes consisting of equilateral rectangular grid cells. Count models predict the number of damage, i.e. the number of plantations and zero models the probability of a landscape being without damage for a given habitat composition. The number of moose damage in neighboring grid cells was a significant predictor in all models. The proportion of mature forest was the most frequent significant variable, and an increasing admixture of mature forests among plantations increased the number and occurrence of damage. The amount of all types of plantations was the second most common significant variable predicting increasing damage along with increasing amount of plantations. An increase in thinning forests as an admixture also increased damage in 1 km2 landscapes in both areas, whereas an increase in pine-dominated thinning forests in Lapland reduced the number of damage in 25 km2 landscapes. An increasing amount of inhabited areas in Ostrobothnia and the length of connecting roads in Lapland reduced the number of damage in 1 and 25 km2 landscapes. Differences in model variables between areas suggest that models of moose damage risk should be adjusted according to characteristics that are specific to the study area.

  • Nikula, Natural Resources Institute Finland (Luke), Bioeconomy and Environment, Ounasjoentie 6, FI-96200 Rovaniemi, Finland ORCID ID:E-mail: ari.nikula@luke.fi (email)
  • Nivala, Natural Resources Institute Finland (Luke), Bioeconomy and Environment, Ounasjoentie 6, FI-96200 Rovaniemi, Finland ORCID ID:E-mail: vesa.nivala@luke.fi
  • Matala, Natural Resources Institute Finland (Luke), Natural resources, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: juho.matala@luke.fi
  • Heliövaara, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: kari.heliovaara@helsinki.fi

Category: Research note

article id 10012, category Research note
Irving U. Hernández-Gómez, Carlos R. Cerdán, Angélica Navarro-Martínez, Dinora Vázquez-Luna, Samaria Armenta-Montero, Edward A. Ellis. (2019). Assessment of the CLASlite forest monitoring system in detecting disturbance from selective logging in the Selva Maya, Mexico. Silva Fennica vol. 53 no. 1 article id 10012. https://doi.org/10.14214/sf.10012
Highlights: The accuracy of CLASlite to detect forest disturbance from selective logging using Landsat imagery was very low (<19.1%); Selective logging impacts was only detected in one case with the highest logging intensity (7 m3 ha–1); CLASlite shows potential in monitoring forest disturbance from tree biomass impacts greater than 900 m2.

Detecting and monitoring forest disturbance from selective logging is necessary to develop effective strategies and polices that conserve tropical forests and mitigate climate change. We assessed the potential of using the remote sensing tool, CLASlite forest monitoring system, to detect disturbance from timber harvesting in four community forests (ejidos) of the Selva Maya on the Yucatan Peninsula, Mexico. Selective logging impacts (e.g. felling gaps, skid trails, logging roads and log landings) were mapped using GPS in the 2014 annual cutting areas (ACAs) of each ejido. We processed and analyzed two pre-harvest Landsat images (2001 and 2013) and one post-harvest image (November 2014) with the CLASlite system, producing maps of degraded, deforested and unlogged areas in each ACA. Based on reference points of disturbed (felling and skidding), deforested (log landings and roads) and unlogged areas in each ACA, we applied accuracy assessments which showed very low overall accuracies (<19.1%). Selective logging impacts, mainly from log landings and new logging road construction, were detected in only one ejido which had the highest logging intensity (7 m3 ha–1).

  • Hernández-Gómez, Facultad de Ciencias Agrícolas, Universidad Veracruzana. Circuito Gonzalo Aguirre Beltrán, Isleta, Xalapa, Veracruz. C.P. 91000, Mexico ORCID ID:E-mail: urielxal@gmail.com
  • Cerdán, Facultad de Ciencias Agrícolas, Universidad Veracruzana. Circuito Gonzalo Aguirre Beltrán, Isleta, Xalapa, Veracruz. C.P. 91000, Mexico ORCID ID:E-mail: ccerdan@uv.mx
  • Navarro-Martínez, El Colegio de la Frontera Sur Av. Centenario km 5.5, Col. Pacto Obrero Campesino s/n. Chetumal, Quintana Roo. C.P. 77014, Mexico ORCID ID:E-mail: manavaster@gmail.com
  • Vázquez-Luna, Facultad de Ingeniería en Sistemas de Producción Agropecuaria, Universidad Veracruzana. Carretera Costera del Golfo Km. 220, C. Agrícola y Ganadera Michapan, Acayucan, Veracruz. C.P. 96000, Mexico ORCID ID:E-mail: divazquez@uv.mx
  • Armenta-Montero, Centro de Investigaciones Tropicales (CITRO), Universidad Veracruzana. Morelos No. 44 y 46, Zona Centro, Xalapa, Veracruz. C.P. 91000, Mexico ORCID ID:E-mail: samaria.am@gmail.com
  • Ellis, Centro de Investigaciones Tropicales (CITRO), Universidad Veracruzana. Morelos No. 44 y 46, Zona Centro, Xalapa, Veracruz. C.P. 91000, Mexico ORCID ID:E-mail: eellis@uv.mx (email)

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