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Articles containing the keyword 'quality'.

Category: Research article

article id 10179, category Research article
Lauri Korhonen, Jaakko Repola, Tomi Karjalainen, Petteri Packalen, Matti Maltamo. (2019). Transferability and calibration of airborne laser scanning based mixed-effects models to estimate the attributes of sawlog-sized Scots pines. Silva Fennica vol. 53 no. 3 article id 10179. https://doi.org/10.14214/sf.10179
Highlights: Attributes of individual sawlog-sized pines estimated by transferring ALS-based models between sites; Mixed effects models were more accurate than k-NN imputation tested earlier; Calibration with a small number of field measured trees improved the accuracy.

Airborne laser scanning (ALS) data is nowadays often available for forest inventory purposes, but adequate field data for constructing new forest attribute models for each area may be lacking. Thus there is a need to study the transferability of existing ALS-based models among different inventory areas. The objective of our study was to apply ALS-based mixed models to estimate the diameter, height and crown base height of individual sawlog sized Scots pines (Pinus sylvestris L.) at three different inventory sites in eastern Finland. Different ALS sensors and acquisition parameters were used at each site. Multivariate mixed-effects models were fitted at one site and the models were validated at two independent test sites. Validation was carried out by applying the fixed parts of the mixed models as such, and by calibrating them using 1–3 sample trees per plot. The results showed that the relative RMSEs of the predictions were 1.2–6.5 percent points larger at the test sites compared to the training site. Systematic errors of 2.4–6.2 percent points also emerged at the test sites. However, both the RMSEs and the systematic errors decreased with calibration. The results showed that mixed-effects models of individual tree attributes can be successfully transferred and calibrated to other ALS inventory areas in a level of accuracy that appears suitable for practical applications.

  • Korhonen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID: http://orcid.org/0000-0002-9352-0114 E-mail: lauri.korhonen@uef.fi (email)
  • Repola, Natural Resources Institute of Finland (Luke), Natural resources, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@luke.fi
  • Karjalainen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: tomikar@uef.fi
  • Packalen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: petteri.packalen@uef.fi
  • 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
article id 9972, category Research article
Jukka Malinen, Harri Kilpeläinen, Erkki Verkasalo. (2018). Validating the predicted saw log and pulpwood proportions and gross value of Scots pine and Norway spruce harvest at stand level by Most Similar Neighbour analyses and a stem quality database. Silva Fennica vol. 52 no. 4 article id 9972. https://doi.org/10.14214/sf.9972
Highlights: Non-parametric prediction together with external stem quality database provides predictions usable for pre-harvest assessment at a stand level; The prediction of Norway spruce assortment recovery and value proved to be more accurate than the predictions for Scots pine; RMSE and bias of unit prices were 3.50 € m–3 and 0.58 € m–3 for pine and 2.60 € m–3 and 0.35 € m–3 for spruce.

Detailed pre-harvest information about the volumes and properties of growing stocks is needed for increased precision in wood procurement planning for just-in-time wood deliveries by cut-to-length (CTL) harvesters. In the study, the non-parametric Most Similar Neighbour (MSN) methodology was evaluated for predicting external quality of Scots pine and Norway spruce, expressed as stem sections fulfilling the saw log dimension and quality requirements of Finnish forest industry, as they affect the recovery of timber assortments and the value of a pre-harvest stand. Effects of external tree quality were evaluated using saw log recovery and saw log reduction caused by stem defects, as well as total timber value (€) and average unit value (€ m–3) in a stand. Root mean square error (RMSE) of saw log recovery and reduction were 9.12 percentile points (pp) for Scots pine and 6.38 pp for Norway spruce stands. In the unit value considerations, the predictions compared with measurements resulted in the RMSE of 3.50 € m–3 and the bias of 0.58 € m–3 in Scots pine stands and 2.60 € m–3, and 0.35 € m–3 in Norway spruce stands, respectively. The presented MSN based approach together with the utilization of the external stem quality database included in the ARVO software could provide dimension and external quality predictions usable for pre-harvest assessment of timber stock at a stand level. This prediction methodology is usable especially in analyses where timber assortment recoveries, values and unit prices are compared when different bucking objectives are used.

  • Malinen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: jukka.malinen@uef.fi (email)
  • Kilpeläinen, Natural Resources Institute Finland (Luke), Production systems, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: harri.kilpelainen@luke.fi
  • Verkasalo, Natural Resources Institute Finland (Luke), Production systems, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: erkki.verkasalo@luke.fi
article id 9948, category Research article
Juha Heiskanen, Ville Hallikainen, Jori Uusitalo, Hannu Ilvesniemi. (2018). Co-variation relations of physical soil properties and site characteristics of Finnish upland forests. Silva Fennica vol. 52 no. 3 article id 9948. https://doi.org/10.14214/sf.9948
Highlights: Atmospheric temperature sum is related to site index H100 as a covariate;Soil pH and water retention at field capacity (FC) are also closely related to H100;Fine fraction is related to water retention at FC, soil layer and site type;Fine fraction co-varies also with temperature sum, H100 and slope.

Physical soil properties have a marked influence on the quality of forest sites and on the preconditions for forest growth and management. In this study, water retention characteristics (WRC) and related physical soil properties in addition to vegetation coverage and tree stand data were studied at upland forest sites in Finland. Fixed and mixed models between soil and site characteristics were formed to estimate physical and hydrologic soil characteristics and the site quality with indirect co-varying variables. In the present data, the site quality index (H100) shows a high coefficient of determination in respect to the temperature sum. It is also related to soil fine fraction content, topsoil pH and water retention at field capacity. The thickness of the humus layer is predictable from the pH and cover of xeric and mesic plant species. The soil fine fraction content (clay + silt) is closely related to water retention at field capacity, the soil layer and site type, and without WRC to the temperature sum and site index and type, as well as the slope angle. The soil bulk density is related to organic matter, depth (layer) or alternatively to organic matter, slope and field estimated textural class (fine, medium, coarse). Water retention characteristics were found to be best determinable by the fine fraction content, depth and bulk density. Water content and air-filled porosity at field capacity are closely related to the fine fraction. This study provides novel models for further investigations that aim at improved prediction models for forest growth, hydrology and trafficability.

  • Heiskanen, Natural Resources Institute Finland (Luke), Soil ecosystems, Neulaniementie 5, FI-70100 Kuopio, Finland ORCID ID:E-mail: juha.heiskanen@luke.fi (email)
  • Hallikainen, Natural Resources Institute Finland (Luke), Applied statistical methods, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: ville.hallikainen@luke.fi
  • Uusitalo, Natural Resources Institute Finland (Luke), Forest technology and logistics, Korkeakoulunkatu 7, FI-33720 Tampere, Finland ORCID ID:E-mail: jori.uusitalo@luke.fi
  • Ilvesniemi, Natural Resources Institute Finland (Luke), Biorefinery and bioproducts, Tietotie 2, FI-02150 Espoo, Finland ORCID ID:E-mail: hannu.ilvesniemi@luke.fi
article id 9914, category Research article
Jun Tanabe, Futoshi Ishiguri, Akira Tamura, Yuya Takashima, Jyunichi Ohshima, Kazuya Iizuka, Shinso Yokota. (2018). Within-tree radial and among-family variations in wood density, microfibril angle, and mechanical properties in Picea glehnii. Silva Fennica vol. 52 no. 2 article id 9914. https://doi.org/10.14214/sf.9914
Highlights: The modulus of elasticity was affected by both microfibril angle and wood density, whereas the modulus of rupture was mainly affected by wood density in Picea glehnii; A larger degree of among-family variation in wood properties was detected in juvenile wood than in mature wood, indicating that genetic improvements in the mechanical properties may be more effective for juvenile wood.

Genetic improvements in the mechanical properties of wood are important in forestry species used for lumber, such as Picea. The within-tree radial and among-family variations for the modulus of elasticity (MOE), modulus of rupture (MOR), and their related traits [i.e., microfibril angle (MFA) of the S2 layer in latewood tracheid and air-dry density (AD)] were evaluated in nine open-pollinated families of Picea glehnii (F. Schmidt) Mast. The radial variation in MOR was mainly affected by AD, whereas MOE was affected by MFA and AD. Higher F-values obtained by analysis of variance and coefficient of variation were observed for all properties at the 6th–15th annual ring, except for AD at the 6th–10th annual ring. This result suggests that the contribution of genetic effect is larger in these highly variable regions. In addition, positive correlation coefficients were obtained between wood properties at the 6th–15th annual ring and mean values of these properties. Therefore, genetic improvements for MOE, MOR, and their related traits in P. glehnii is likely to be more effective in juvenile wood, specifically at the 6th–15th annual ring from the pith.

  • Tanabe, Faculty of Education, Chiba University, Chiba, 263-8522, Japan ORCID ID:E-mail: tanabe_j@chiba-u.jp (email)
  • Ishiguri, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan ORCID ID:E-mail: ishiguri@cc.utsunomiya-u.ac.jp
  • Tamura, Forest Tree Breeding Center, Forestry and Forest Products Research Institute, Hitachi, 319-1301, Japan ORCID ID:E-mail: akirat@affrc.go.jp
  • Takashima, Forest Tree Breeding Center, Forestry and Forest Products Research Institute, Hitachi, 319-1301, Japan ORCID ID:E-mail: ytakashima@ffpri.affrc.go.jp
  • Ohshima, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan ORCID ID:E-mail: joshima@cc.utsunomiya-u.ac.jp
  • Iizuka, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan ORCID ID:E-mail: kiizuka@cc.utsunomiya-u.ac.jp
  • Yokota, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan ORCID ID:E-mail: yokotas@cc.utsunomiya-u.ac.jp
article id 7816, category Research article
Pentti Niemistö, Harri Kilpeläinen, Eero Poutiainen. (2018). Effect of first thinning type and age on growth, stem quality and financial performance of a Scots pine stand in Finland. Silva Fennica vol. 52 no. 2 article id 7816. https://doi.org/10.14214/sf.7816
Highlights: Early commercial first thinning at the top height of 11 m with tree selection targeting high quality of remaining stems was more profitable in a Scots pine stand than thinning from below at similar time or delayed thinning 10 years later; After early first thinning only one intermediate thinning was needed, but a late thinning at age of 60 years was feasible in connection with increased amount of high quality butt logs after artificial pruning; The optimal rotation period for a Scots pine stand using a lower interest rate of 1% was 80–85 years depending on the thinning pattern. With a higher rate of 4%, the optimal rotation took only 60 years.

The objective of the study was to ascertain the effects of tree selection (thinning from below, from above and according to stem quality) and timing of first commercial thinning (early and delayed) on the growth, yield and quality of trees in a Scots pine (Pinus sylvestris L.) stand. A long-term field experiment (25 years) was measured in 5-year periods and the further development was simulated with growth and yield models to final cuttings using alternative rotation periods of 55–85 years. The measurements included also the exact location and type of technical defects detected on all trees in the experimental plots. The measured volume increment per unit area during the study period, 25 years after the early thinning stage was the lowest in the plots thinned from below, and the highest in the plots thinned from above or in the delayed thinning plots. However, the largest volume of saw logs during the whole rotation of 80 years was yielded after early first thinning according to the quality. The largest volume of very high-quality butt logs was produced by pruning connected with early thinning from above, and a smaller volume after early thinning according to stem quality but no after thinning from below or delayed first thinning. Without pruning an early quality thinning with one intermediate thinning was the most profitable thinning treatment in the Scots pine stand regardless the rotation length or the interest rate used. By interest rates of 1% and 2%, the optimal rotations were 80–85 years and 70 years respectively. A late thinning at the age of 60 year with long rotation was profitable only for the pruned pine stands with a low interest rate.

  • 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, FI-80100 Joensuu, Finland ORCID ID:E-mail: harri.kilpelainen@luke.fi
  • Poutiainen, Oulu ORCID ID:E-mail: eero1.poutiainen@dnainternet.net
article id 9923, category Research article
Annika Kangas, Terje Gobakken, Stefano Puliti, Marius Hauglin, Erik Naesset. (2018). Value of airborne laser scanning and digital aerial photogrammetry data in forest decision making. Silva Fennica vol. 52 no. 1 article id 9923. https://doi.org/10.14214/sf.9923
Highlights: Airborne laser scanning (ALS) and digital aerial photogrammetry (DAP) are nearly equally valuable for harvest scheduling decisions even though ALS data is more precise; Large underestimates of stand volume are most dangerous errors for forest owner because of missed cutting probabilities; Relative RMSE of stand volume and the mean volume in a test area explain 77% of the variation between the expected losses due to errors in the data in the published studies; Increasing the relative RMSE of volume by 1 unit, increased the losses in average by 4.4 € ha–1.

Airborne laser scanning (ALS) has been the main method for acquiring data for forest management planning in Finland and Norway in the last decade. Recently, digital aerial photogrammetry (DAP) has provided an interesting alternative, as the accuracy of stand-based estimates has been quite close to that of ALS while the costs are markedly smaller. Thus, it is important to know if the better accuracy of ALS is worth the higher costs for forest owners. In many recent studies, the value of forest inventory information in the harvest scheduling has been examined, for instance through cost-plus-loss analysis. Cost-plus-loss means that the quality of the data is accounted for in monetary terms through calculating the losses due to errors in the data in the forest management planning context. These costs are added to the inventory costs. In the current study, we compared the losses of ALS and DAP at plot level. According to the results, the data produced using DAP are as good as data produced using ALS from a decision making point of view, even though ALS is slightly more accurate. ALS is better than DAP only if the data will be used for more than 15 years before acquiring new data, and even then the difference is quite small. Thus, the increased errors in DAP do not significantly affect the results from a decision making point of view, and ALS and DAP data can be equally well recommended to the forest owners for management planning. The decision of which data to acquire, can thus be made based on the availability of the data on first hand and the costs of acquiring it on the second hand.

  • Kangas, Natural Resources Institute Finland (Luke), Bioeconomy and environment, P.O. Box 68, FI-80170 Joensuu, Finland ORCID ID:E-mail: annika.kangas@luke.fi (email)
  • Gobakken, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway ORCID ID:E-mail: terje.gobakken@nmbu.no
  • Puliti, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway ORCID ID:E-mail: stefano.puliti@nibio.no
  • Hauglin, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway ORCID ID:E-mail: marius.hauglin@nmbu.no
  • Naesset, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway ORCID ID:E-mail: erik.naesset@nmbu.no
article id 1665, category Research article
Lauri Haataja, Ville Kankaanhuhta, Timo Saksa. (2018). Reliability of self-control method in the management of non-industrial private forests. Silva Fennica vol. 52 no. 1 article id 1665. https://doi.org/10.14214/sf.1665
Highlights: Self-control method was found reliable at the main stages of the forest regeneration process; Only slight overestimation was found in self-control results of soil preparation and planting and small underestimation in self-control of young stand management; Diverse utilizing of self-control data is possible in support of service providers operations.
This study seeks to determine the extent to which self-control data can be relied upon in the management of private forests. Self-control (SC) requires the forest workers to evaluate their own work quality to ensure the clients’ needs are met in terms of soil preparation, planting and young stand management. Self-control data were compared to an independent evaluation of the same worksites. Each dataset had a hierarchical structure (e.g., sample plot, regeneration area and contractor), and key quality indicators (i.e., number of prepared mounds, planted seedlings or crop trees) were measured for each plot.  Self-control and independent-assessments (IA) were analyzed by fitting a multi-level multivariate model containing explanatory variables. No significant differences were observed in terms of soil preparation (number of mounds) or young stand management (number of crop trees) between self-control and independent-assessments. However, the self-control planting data included a slight but significant overestimation of the number of planted seedlings. Discrepancies are discussed in terms of sampling error and other explanatory factors. According to overall results, self-control methods are reliable at every stage of the forest regeneration process. As such, the diverse utilizing of self-control data is possible in support of service providers operations.
  • Haataja, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: lauritapiohaataja@gmail.com (email)
  • Kankaanhuhta, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: ville.kankaanhuhta@luke.fi
  • Saksa, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: timo.saksa@luke.fi
article id 1682, category Research article
Jiří Korecký, Yousry A. El-Kassaby. (2016). Pollination dynamics variation in a Douglas-fir seed orchard as revealed by microsatellite analysis. Silva Fennica vol. 50 no. 4 article id 1682. https://doi.org/10.14214/sf.1682
Highlights: Important characteristics such as parental reproductive success, pollen contamination, and selfing rate in the second generation Douglas-fir seed orchard have been estimated; Since this research is a part of a multi-year study, outputs were compared to those from two other years; Results are in line and differences in pollination dynamics across years are attributable to the various crop management practices.

As part of a multi-year monitoring study of pollination dynamics in a second generation Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seed orchard, we estimated with the aid of eight microsatellite markers three important reproductive biology characteristics affecting the genetic worth and diversity of seed crops; namely parental reproductive success, pollen contamination, and selfing rate. The obtained results were compared to those from two previous years to gauge appropriate seed crop management practices and ultimately allow approximate generalization of seed crop genetic quality. We determined that 80% of parental gametes were produced by 52% of the parents, 13% of paternal gametes resulted from pollen contamination (i.e., gene flow), and 12% of the seed were the product of selfing. The obtained results were in line with those observed for 2005 and 2009 where 80% of gametes being produced by 37–48% of the parents, 10–18% pollen contamination, and 15–17% selfing rate. The observed reproductive biology parameters differences are attributable to the various crop management practices implemented (i.e., bloom delay and supplemental-mass-pollination) across years and calls for justification due to the observed minimal differences on seed crops genetic quality.

  • Korecký, Department of Genetics and Physiology of Forest Trees, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Praha 6, 165 21, Czech Republic ORCID ID: http://orcid.org/0000-0001-7859-1750 E-mail: korecky@fld.czu.cz (email)
  • El-Kassaby, Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada ORCID ID: http://orcid.org/0000-0002-4887-8977 E-mail: y.el-kassaby@ubc.ca
article id 1475, category Research article
Jiaxi Wang, Haiqun Yu, Guolei Li, Feng Zhang. (2016). Growth and nutrient dynamics of transplanted Quercus variabilis seedlings as influenced by pre-hardening and fall fertilization. Silva Fennica vol. 50 no. 2 article id 1475. https://doi.org/10.14214/sf.1475
Highlights: High pre-hardening fertilization favored seedling growth and nutrient storage at the rapid growth and hardening phases following transplantation. Overall, high fall fertilization was beneficial only at the hardening phase; The combination of 100 mg N seedling–1 during pre-hardening with 36 mg N seedling–1 during hardening was recommended for satisfactory transplanting performance for Quercus variabilis.

Stored nutrient reserves are closely correlated with survival and growth of transplanted seedlings. Previous studies have proven that combining pre-hardening fertilization (PF) with fall fertilization (FF) built seedling nutrient reserves more effectively; however, their effect on transplanting performance is poorly documented. We investigated the independent and interacting effects of 2 levels of PF and 4 levels of FF on seedling growth, nutrient acquisition and accumulation during different growth phases 1 year after transplanting of Quercus variabilis Blume in a nursery. High PF benefited nutrient reserves and subsequent transplanted seedling growth and tissue nutrient storage at the end of the rapid growth and hardening phases. Fall fertilization with 36 mg N increased stem dry mass and tissue nutrient content at the end of the hardening phase. At the conclusion of establishment, PF and FF showed a significant interaction for N and K uptake from soil. At the end of the rapid growth and hardening phases, high PF consistently increased nutrient uptake. Enhanced N and K uptake occurred following application of 36 mg N of FF at the end of the hardening phase. Distinct roles for PF and FF on 3 phases of transplanted seedlings demonstrated the necessity to evaluate fertilization in terms of nutrient reserves and subsequent transplanting performance in consecutive phases. Combining 100 mg N seedling–1 during pre-hardening with 36 mg N seedling–1 during fall yielded ideal transplanting performance for Quercus variabilis seedlings.

  • Wang, Key Laboratory for Silviculture and Conservation, Ministry of Education; Beijing Laboratory of Urban and Rural Ecological Environment, Beijing Forestry University, 35 East Qinghua Road, Haidian District, Beijing 100083, China ORCID ID:E-mail: wjx198979@163.com
  • Yu, Beijing Forestry Carbon Administration, room 201, No.1 Xiao Huang Zhuang Bei Jie, Dongcheng District, Beijing 100013, China ORCID ID:E-mail: yuhq@bfdic.com
  • Li, Key Laboratory for Silviculture and Conservation, Ministry of Education; Beijing Laboratory of Urban and Rural Ecological Environment, Beijing Forestry University, 35 East Qinghua Road, Haidian District, Beijing 100083, China ORCID ID:E-mail: glli226@163.com (email)
  • Zhang, Beijing Forestry Carbon Administration, room 201, No.1 Xiao Huang Zhuang Bei Jie, Dongcheng District, Beijing 100013, China ORCID ID:E-mail: zhangf@bfdic.com
article id 1393, category Research article
Werner Poschenrieder, Andreas Rais, Jan-Willem G. van de Kuilen, Hans Pretzsch. (2016). Modelling sawn timber volume and strength development at the individual tree level – essential model features by the example of Douglas fir. Silva Fennica vol. 50 no. 1 article id 1393. https://doi.org/10.14214/sf.1393
Highlights: An individual tree timber growth and quality model toolbox was designed; It realistically predicts an increase of bending strength with planting density; Prediction was shown to be based on consideration of essential intrinsic variables; Height‑diameter‑allometry depending on planting density was effective; Consideration of cambial age and knot area ratio was crucial.

We designed a streamlined timber growth and quality model that aims at the effect of stand management on the efficiency of wood resource use. Applying the R based module toolbox to experimental plots of Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) we analysed essential model features for reflecting the influence of planting density on board strength. The current version realistically predicted a significant increase of centre board bending strength at tree age 40 with initial stand density. Model performance gained clear advantage from a) parameterisation of height to diameter allometry as dependent on planting density b) consideration of cambial age and cross‑sectional knot area in board strength computation. Crown shape was less decisive. The model produced a significant effect of planting density even after a whole rotation period of 70 years as well as a realistic spectrum of board bending strength.

  • Poschenrieder, Technische Universität München, Chair of Forest Growth and Yield Science, Hans Carl von Carlowitz Platz 2, 85354 Freising, Germany ORCID ID: http://orcid.org/0000-0002-9028-8583 E-mail: Werner.Poschenrieder@lrz.tum.de (email)
  • Rais, Technische Universität München, Chair of Forest Growth and Yield Science, Hans Carl von Carlowitz Platz 2, 85354 Freising, Germany; Technische Universität München, Holzforschung München, Winzererstrasse 45, 80797 Munich, Germany ORCID ID:E-mail: Andreas.Rais@hfm.tum.de
  • van de Kuilen, Technische Universität München, Holzforschung München, Winzererstrasse 45, 80797 Munich, Germany ORCID ID:E-mail: vandekuilen@hfm.tum.de
  • Pretzsch, Technische Universität München, Chair of Forest Growth and Yield Science, Hans Carl von Carlowitz Platz 2, 85354 Freising, Germany ORCID ID:E-mail: Hans.Pretzsch@lrz.tum.de
article id 1382, category Research article
Juha Laitila, Johanna Routa. (2015). Performance of a small and a medium sized professional chippers and the impact of storage time on Scots pine (Pinus sylvestris) stem wood chips characteristics. Silva Fennica vol. 49 no. 5 article id 1382. https://doi.org/10.14214/sf.1382
Highlights: The storage time of pulpwood had no significant effect on particle size distribution in any chip size classes; The study confirms the knowledge that chipping time consumption is inversely proportional to engine power and grapple load size in feeding; The use of an narrower 80 mm × 80 mm sieve on Scots pine material does not seem to offer any benefit compared to a 100 mm × 100 mm sieve from the perspective of chip quality.

The primary aim of this study was to clarify the chipping productivity and fuel consumption of tractor-powered and truck-mounted drum chippers when chipping pine pulpwood at a terminal. The secondary aim was to evaluate the impact of wood storage time on the chemical and physical technical specifications of wood chips by chipping pulpwood from eight different storage time groups, using Scots pine (Pinus sylvestris) pulpwood stems logged between 2 and 21 months previously at the terminal with the above-mentioned chippers. Thirdly, the impact of sieve mesh size on the particle size distribution of wood chips from different age groups was compared by using an 80 mm × 80 mm sieve for a tractor-powered chipper and a 100 mm × 100 mm sieve for a truck-mounted chipper. With both chippers, the chipping productivity grew as a function of grapple load weight. The average chipping productivity of the tractor-powered chipper unit was 19 508 kg (dry mass) per effective hour (E0h), and for the truck-mounted chipper the average productivity was 31 184 kg E0h–1. The tractor-powered drum chipper’s fuel consumption was 3.1 litres and for the truck-mounted chipper 3.3 litres per chipped 1000 kg (dry mass). The amount of extractives or volatiles did not demonstrate any statistically significant differences between storage time groups. The particle size distributions with both chippers were quite uniform, and the storage time of pulpwood did not have a significant effect on the particle size distribution in any chip size classes. One reason for this might be that the basic density of chipped wood was homogenous and there was no statistical difference between different storage times. The use of new sharp knives is likely to have affected chip quality, as witnessed by the absence of oversized particles and the moderate presence of fines. The use of narrower 80 mm × 80 mm sieves on Scots pine material does not seem to offer any benefit compared to 100 mm × 100 mm from the chip quality point of view.

  • Laitila, Natural Resources Institute Finland (Luke), Bio-based business and industry, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: juha.laitila@luke.fi (email)
  • Routa, Natural Resources Institute Finland (Luke), Bio-based business and industry, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: johanna.routa@luke.fi
article id 1340, category Research article
Mostafa Farhadi, Mulualem Tigabu, Per Christer Odén. (2015). Near Infrared Spectroscopy as non-destructive method for sorting viable, petrified and empty seeds of Larix sibirica. Silva Fennica vol. 49 no. 5 article id 1340. https://doi.org/10.14214/sf.1340
Highlights: Near Infrared spectroscopy discriminates filled-viable, empty and petrified seeds of Larix sibirica with 98%, 82% and 87% accuracy, respectively based on spectral differences attributed to moisture and storage reserves; The classification accuracy reached 100% when sorting seeds into viable and non-viable class; The results demonstrate that NIR spectroscopy has great potential as non-destructive sorting technique to upgrade seed lot quality.

Larix sibirica Ledeb. is one of the promising timber species for planting in the boreal ecosystem; but poor seed lot quality is the major hurdle for production of sufficient quantity of planting stocks. Here, we evaluated the potential of Near Infrared (NIR) Spectroscopy for sorting viable and non-viable seeds, as the conventional sorting technique is inefficient. NIR reflectance spectra were collected from single seeds, and discriminant models were developed with Orthogonal Projections to Latent Structure – Discriminant Analysis (OPLS-DA). The computed model predicted the class membership of filled-viable, empty and petrified seeds in the test set with 98%, 82% and 87% accuracy, respectively. When two-class OPLS-DA model was fitted to discriminate viable and non-viable (empty and petrified seeds combined), the predicted class membership of test set samples was 100% for both classes. The origins of spectral differences between non-viable (petrified and empty) and viable seeds were attributed to differences in seed moisture content and storage reserves. In conclusion, the result provides evidence that NIR spectroscopy is a powerful non-destructive method for sorting non-viable seeds of Larix sibirica; thus efforts should be made to develop on-line sorting system for large-scale seed handling.

  • Farhadi, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: mostafa.farhadi@slu.se
  • Tigabu, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: mulualem.tigabu@slu.se (email)
  • Odén, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: per.oden@slu.se
article id 1280, category Research article
Juha Laitila, Tapio Ranta, Antti Asikainen, Eero Jäppinen, Olli-Jussi Korpinen. (2015). The cost competitiveness of conifer stumps in the procurement of forest chips for fuel in Southern and Northern Finland. Silva Fennica vol. 49 no. 2 article id 1280. https://doi.org/10.14214/sf.1280
Highlights: Pre-grinding and integrated screening is a way of guaranteeing fuel quality, but, when the stumps’ ash content is six per cent or below, the procurement costs are higher than with grinding of stumps at the plant. Because of high transportation costs, stump harvesting is the most profitable in Southern Finland, where there is greater availability of stumps than in Northern Finland.
The aim of this study was to evaluate cost competitiveness, at regional level, of various systems for stump transportation and grinding, and to compare the results to the procurement costs of delimbed stems from early thinnings at the stand and regional level. The accumulation and procurement costs of stumps and delimbed stems were estimated within a 100-kilometer radius from two power plants located in Kouvola and in Kajaani. The analyses were performed as simulated treatments in clear cuts and thinnings of young stands, using existing productivity and cost functions, alternative ash percentages for stump wood, and yield calculations based on the forest industry regeneration felling stand data and the sample plots data of the National Forest Inventory of Finland. The results were expressed as Euros per solid cubic meter (€ m–3) and Euros per megawatt hour (€ MWh–1). The results highlight the need to improve stump fuel quality and increase the heating value. The procurement cost of stumps was about 1 € MWh–1 lower in Kouvola compared to Kajaani, when using conceivable ash content of 6% for stumps ground at the plant, and ash content of 1.5% for stumps pre-ground at the roadside landing. The procurement costs of stumps were, on average, 0.55 € MWh–1 lower compared to delimbed stems in Kouvola, and on average 0.6 € MWh–1 higher in Kajaani. Pre-grinding and integrated screening is a feasible way to guarantee the fuel quality expressed as ash content already at roadside landings, but the procurement costs are higher compared to grinding stumps at the plant, when the ash content of ground stumps is 6% or less.
  • Laitila, Natural Resources Institute Finland (Luke), Bio-based Business and Industry, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: juha.laitila@metla.fi (email)
  • Ranta, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli, Finland ORCID ID:E-mail: tapio.ranta@lut.fi
  • Asikainen, Natural Resources Institute Finland (Luke), Bio-based Business and Industry, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: antti.asikainen@metla.fi
  • Jäppinen, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli, Finland ORCID ID:E-mail: eero.jappinen@lut.fi
  • Korpinen, Lappeenranta University of Technology, Sammonkatu 12, FI-50130 Mikkeli, Finland ORCID ID:E-mail: olli-jussi.korpinen@lut.fi
article id 1217, category Research article
Ulrich J. Wolfsmayr, Peter Rauch. (2014). Primary forest fuel supply chain: assessing barriers and drivers for the modal shift from truck to train. Silva Fennica vol. 48 no. 5 article id 1217. https://doi.org/10.14214/sf.1217
Highlights: For combined heat and power plants in Austria procuring forest fuels, the most competitive transport mode is road transport using walking-floor trucks; The main barriers for a modal shift are the plant managers’ negative experiences with the railroad; Rail transport has its benefits, when high volumes are needed and transport distances are long.
Multimodal primary forest fuel (PFF) transport using the railroad for main haulage has been quite uncommon to present, although it could provide considerable advantages in terms of economical, ecological and social parameters. Accordingly, the objective of this paper is to assess barriers and drivers for the modal shift from truck to train. As methodological tool, we are using the concept of Quality Function Deployment (QFD) with the House of Quality (HoQ) – an approach that has not been used in forest management so far. As the most important barriers for the modal shift from truck to train in PFF transport in Austria, the following were identified: (i) bioenergy plant managers have a negative opinion and negative experience regarding the railroad in terms of high prices, a lot of bureaucracy, etc.; (ii) absence of rail sidings or relatively short rail sidings not suitable for block trains; and (iii) unwillingness to invest in new supply or unloading systems. On the contrary, the most important drivers for a modal shift are: (i) multimodal PFF supply chains using trains can provide high volumes; (ii) increasing catchment areas for larger CHP plants result in increasing transport distances; and (iii) rail transport has less negative environmental and social impact than road transport.
  • Wolfsmayr, University of Natural Resources and Life Sciences, Vienna, Gregor Mendel Straße 33, A-1180 Wien, Austria ORCID ID:E-mail: ulrich.wolfsmayr@boku.ac.at (email)
  • Rauch, University of Natural Resources and Life Sciences, Vienna, Gregor Mendel Straße 33, A-1180 Wien, Austria ORCID ID:E-mail: peter.rauch@boku.ac.at
article id 1217, category Research article
Ulrich J. Wolfsmayr, Peter Rauch. (2014). Primary forest fuel supply chain: assessing barriers and drivers for the modal shift from truck to train. Silva Fennica vol. 48 no. 5 article id 1217. https://doi.org/10.14214/sf.1217
Highlights: For combined heat and power plants in Austria procuring forest fuels, the most competitive transport mode is road transport using walking-floor trucks; The main barriers for a modal shift are the plant managers’ negative experiences with the railroad; Rail transport has its benefits, when high volumes are needed and transport distances are long.
Multimodal primary forest fuel (PFF) transport using the railroad for main haulage has been quite uncommon to present, although it could provide considerable advantages in terms of economical, ecological and social parameters. Accordingly, the objective of this paper is to assess barriers and drivers for the modal shift from truck to train. As methodological tool, we are using the concept of Quality Function Deployment (QFD) with the House of Quality (HoQ) – an approach that has not been used in forest management so far. As the most important barriers for the modal shift from truck to train in PFF transport in Austria, the following were identified: (i) bioenergy plant managers have a negative opinion and negative experience regarding the railroad in terms of high prices, a lot of bureaucracy, etc.; (ii) absence of rail sidings or relatively short rail sidings not suitable for block trains; and (iii) unwillingness to invest in new supply or unloading systems. On the contrary, the most important drivers for a modal shift are: (i) multimodal PFF supply chains using trains can provide high volumes; (ii) increasing catchment areas for larger CHP plants result in increasing transport distances; and (iii) rail transport has less negative environmental and social impact than road transport.
  • Wolfsmayr, University of Natural Resources and Life Sciences, Vienna, Gregor Mendel Straße 33, A-1180 Wien, Austria ORCID ID:E-mail: ulrich.wolfsmayr@boku.ac.at (email)
  • Rauch, University of Natural Resources and Life Sciences, Vienna, Gregor Mendel Straße 33, A-1180 Wien, Austria ORCID ID:E-mail: peter.rauch@boku.ac.at
article id 1211, category Research article
Xiao Chen, Deborah Page-Dumroese, Ruiheng Lv, Weiwei Wang, Guolei Li, Yong Liu. (2014). Interaction of initial litter quality and thinning intensity on litter decomposition rate, nitrogen accumulation and release in a pine plantation. Silva Fennica vol. 48 no. 4 article id 1211. https://doi.org/10.14214/sf.1211
Highlights: Litter quality and thinning showed an interaction on one year litter decomposition rates, N accumulation, and net N release; N accumulated until the underlying critical acid-unhydrolyzable residue to nitrogen ratio (approximately 57–69) was met; Increased N concentration in litter and thinning intensity induced rapid litter decomposition and N cycling in coniferous plantation with a slow decomposition rate.
Thinning alters litter quality and microclimate under forests. Both of these two changes after thinning induce alterations of litter decomposition rates and nutrient cycling. However, a possible interaction between these two changes remains unclear. We placed two types of litter (LN, low N concentration litter; HN, high N concentration litter) in a Chinese pine (Pinus tabulaeformis Carrière) plantation under four thinning treatments to test the impacts of litter quality, thinning or their combination on decomposition rate and N cycling. In our study, N was accumulated to approach an underlying critical acid-unhydrolyzable residue to nitrogen ratio (approximately 57–69) in litter. Moreover, an interaction between litter quality and thinning on decomposition rates, N accumulation and net release did exist. On one hand, one year decomposition rate of LN was elevated after thinning while that of HN remained the same or even lower (under light thinning); N accumulation of LN declined with light thinning and was restored with the increase of thinning intensity whereas that of HN did not decline with thinning and increased under heavy thinning; Net N release from LN was only found in light and heavy thinning while that from HN was found in all treatments, moreover net N release from LN and HN were both elevated under heavy thinning. On the other hand, HN decomposed faster, accumulated less and released more N than LN did under all treatments. Generally, high N concentration in litter and high-intensity thinning can lead to rapid litter decomposition and N cycling in coniferous plantations.
  • Chen, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing, 100083, China ORCID ID:E-mail: chenxiao_0123@126.com
  • Page-Dumroese, U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, 1221 South Main Street, Moscow, ID 83843, USA ORCID ID:E-mail: ddumroese@fs.fed.us
  • Lv, College of Plant Science and Technology, Tarim University, Alar Xinjiang, 843300, China ORCID ID:E-mail: lvrh514723@126.com
  • Wang, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing, 100083, China ORCID ID:E-mail: fuyuerdejia@126.com
  • Li, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing, 100083, China ORCID ID:E-mail: glli226@163.com
  • Liu, Key Laboratory for Silviculture and Conservation of Ministry of Education, Beijing Forestry University, Beijing, 100083, China ORCID ID:E-mail: lyong@bjfu.edu.cn (email)
article id 980, category Research article
Atte Komonen, Panu Halme, Mari Jäntti, Tuuli Koskela, Janne S. Kotiaho, Tero Toivanen. (2014). Created substrates do not fully mimic natural substrates in restoration: the occurrence of polypores on spruce logs. Silva Fennica vol. 48 no. 1 article id 980. https://doi.org/10.14214/sf.980
Highlights: Polypore communities were more homogeneous among created than among natural logs; The old-growth forest indicator Phellinus ferrugineofuscus occurred frequently on natural logs, but occupied only a few created logs; Results show that created logs do not fully mimic natural logs.
Many protected areas have been under intensive forest management prior to protection and thus lack natural ecosystem structures and dynamics. Dead wood is a key structure in forests harboring hundreds of threatened species. We investigated the ecological success of dead wood creation as a boreal forest restoration measure. We analysed whether the polypore communities of chain-saw felled and girdled (subsequently fallen) Norway spruce (Picea abies (L.) H. Karst.) logs differ from naturally formed spruce logs of similar decay stage and size. The study was conducted in Leivonmäki National Park in central Finland 8 years after the restoration measures. The average number of polypore species was highest on the chain-saw felled logs and most of the common polypore species were most frequent on this substrate. However, among the natural logs, number of species increased more steeply with increasing number of logs, suggesting greater variation in community composition on this substrate. The old-growth forest indicator Phellinus ferrugineofuscus occurred frequently on natural logs, occupied a few girdled logs but was absent from chain-saw felled logs. Our results show that from the polypore perspective created logs do not fully mimic natural logs, suggesting that creating substrates for species may pose a challenge for restoration.
  • Komonen, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: atte.komonen@jyu.fi (email)
  • Halme, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: panu.halme@jyu.fi
  • Jäntti, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: mari.j.jantti@student.jyu.fi
  • Koskela, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: tuuli.e.koskela@student.jyu.fi
  • Kotiaho, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: janne.kotiaho@jyu.fi
  • Toivanen, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland; Current: Birdlife Finland, Annankatu 29 A 16, FI-00100 Helsinki, Finland ORCID ID:E-mail: tero.toivanen@birdlife.fi
article id 1071, category Research article
Ursula Kretschmer, Nadeschda Kirchner, Christopher Morhart, Heinrich Spiecker. (2013). A new approach to assessing tree stem quality characteristics using terrestrial laser scans. Silva Fennica vol. 47 no. 5 article id 1071. https://doi.org/10.14214/sf.1071
Highlights: Minimal deviations of the bark surface can be detected and visualized based on terrestrial laser scan data; Additionally the geometrical properties of bark scars and branched knots can be assessed; Two methods using two different approaches are presented: (1) a method using intensity data and (2) a method using bark surface models.
This paper presents an approach to assess and measure bark characteristics as indicators of wood quality using terrestrial laser scan data. In addition to the detection and measurement by use of the intensity information of the scan data a new approach was established. Bark surface models are calculated for each tree. They offer the representation of the bark as a height model. The reference is the tree stem approximated by a chain of cylinders. Minimal deviations of the bark surface can be detected and visualized and the geometrical properties of bark scars and branched knots can be assessed. Results of the measurement of 18 scars are presented using the two approaches: (1) a method using intensity data or (2) using bark surface models. The selection of the adequate approach depends on the stem characteristics. In a next step, methods for automatic measurement of bark scars will be developed.
  • Kretschmer, Chair of Forest Growth, Albert-Ludwigs-University Freiburg, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID ID:E-mail: ursula.kretschmer@iww.uni-freiburg.de (email)
  • Kirchner, VOLKE Consulting Engineers GmbH, Schätzweg 7-9, 80935 München, Germany ORCID ID:E-mail: nadeschda.kirchner@volke.muc.de
  • Morhart, Chair of Forest Growth, Albert-Ludwigs-University Freiburg, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID ID:E-mail: christopher.morhart@iww.uni-freiburg.de
  • Spiecker, Chair of Forest Growth, Albert-Ludwigs-University Freiburg, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID ID:E-mail: instww@uni-freiburg.de
article id 901, category Research article
Luis A. Apiolaza, Rosa M. Alzamora. (2013). Building deployment portfolios for genotypes under performance instability. Silva Fennica vol. 47 no. 1 article id 901. https://doi.org/10.14214/sf.901
We used portfolio theory to analyze the tradeoffs between returns and performance instability of deployment units for Pinus radiata D. Don. We considered three groups of 34 trees each grown to produce appearance lumber, structural lumber, or both. Risk was based on the variability of tree returns in scenarios of changing volume, wood stiffness and presence of resin defects due to genotype by environment interaction inducing both changes of scale and differential tree response to environmental scenarios. The return of structural trees was highly variable with a mean of 3.11 NZ $/stem/year, followed by appearance-structural trees (3.48 NZ $/stem/year). In contrast, appearance trees had the lowest returns (1.99 NZ $/stem/year) and variability. The portfolio model selected structural trees in high-risk scenarios, but selection was apportioned between structural and appearance-structural trees as the risk decreased. The model selected only appearance trees for high-risk aversion. The analysis also considered silvicultural regimes, where the appearance-structural regime was selected under high variability. As risk decreased the appearance grades regime was also selected. The structural regime was rarely selected due to the variability of stiffness between trees. Using genotypes improved for stiffness could increase the expected value and reduce variability for structural purposes, making the structural regime more appealing.
  • Apiolaza, School of Forestry, University of Canterbury, Private Bag 4800, 8042 Canterbury, New Zealand ORCID ID:E-mail: luis.apiolaza@canterbury.ac.nz (email)
  • Alzamora, Instituto de Manejo Forestal, Universidad Austral, Valdivia, Chile ORCID ID:E-mail: ralzamor@uach.cl
article id 69, category Research article
Tarja Wallenius, Risto Laamanen, Jussi Peuhkurinen, Lauri Mehtätalo, Annika Kangas. (2012). Analysing the agreement between an Airborne Laser Scanning based forest inventory and a control inventory – a case study in the state owned forests in Finland. Silva Fennica vol. 46 no. 1 article id 69. https://doi.org/10.14214/sf.69
Airborne laser scanning based forest inventories have recently shown to produce accurate results. However, the accuracy varies according to the test area and used methodology and therefore, an unambiguous and practical quality assessment will be needed as a part of each inventory project. In this study, the accuracy of an ALS inventory was evaluated with a field sampling based control inventory. The agreement between the ALS inventory and the control inventory was analysed with four methods: 1) root mean square error (RMSE) and bias, 2) scatter plots with 95% confidence intervals, 3) Bland-Altman plots and 4) tolerance limits within Bland-Altman plots. Each method has its own special features which have to be taken into account when the agreement is analysed. The pre-defined requirements of the ALS inventory were achieved. A simplified control inventory approach with a slightly narrower focus is proposed to be used in the future. The Bland-Altman plots with the tolerance limits are proposed to be used in quality assessments of operational ALS inventories. Further studies to improve the efficiency of quality assessment are needed.
  • Wallenius, Metsähallitus, P.O. Box 94, FI-01301 Vantaa, Finland ORCID ID:E-mail: tarja.wallenius@metsa.fi (email)
  • Laamanen, Metsähallitus, P.O. Box 94, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Peuhkurinen, Oy Arbonaut Ltd, Helsinki, Finland ORCID ID:E-mail:
  • Mehtätalo, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Kangas, University of Helsinki, Department of Forest Sciences, Helsinki, Finland ORCID ID:E-mail:
article id 107, category Research article
Jaana Luoranen, Risto Rikala, Heikki Smolander. (2011). Machine planting of Norway spruce by Bracke and Ecoplanter: an evaluation of soil preparation, planting method and seedling performance. Silva Fennica vol. 45 no. 3 article id 107. https://doi.org/10.14214/sf.107
We evaluated the effects of planting date and planting machine (Bracke: three machines, 69 regeneration areas in three years; Ecoplanter: six areas, two years) on the quality and field performance one and three years after planting of Norway spruce (Picea abies (L.) Karst.) seedlings in central Finland. Both machine types planted on average 1800 seedlings per hectare, and after three years approximately 1600 (Bracke) and 1200 (Ecoplanter) were still alive. This study suggests that planting with a Bracke machine can achieve better regeneration rates than those observed in privately-owned Finnish forests. We characterized the quality of mounding and planting with the Bracke machine as excellent and that of the Ecoplanter as good. The soil preparation method of the Ecoplanter produced humus-rich mounds where seedlings were susceptible to pine weevils and consequently suffered higher mortality. Different machines were used in different regional areas and each machine was operated by different driver/s which may have influenced the results. No negative effects of planting date were observed. Seedling growth decreased if they were tall in relation to their root plug volume, grown too densely in the nursery, and if stored in the field for several months prior to planting. We conclude that mechanized planting is successful when the soil preparation method produces mounds covered by purely mineral soil. Planting from May to the end of September is suitable for seedlings intended for use during this period.
  • Luoranen, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@metla.fi (email)
  • Rikala, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Smolander, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 106, category Research article
Hannu Hökkä, Heli Hyttinen, Hannu Marttila, Juha Jämsen, Bjørn Kløve. (2011). Effect of peak runoff control method on growth of Scots pine stands on drained peatlands in central Finland. Silva Fennica vol. 45 no. 3 article id 106. https://doi.org/10.14214/sf.106
In drained peatland forests ditch networks need regular maintenance operations in order to sustain their drainage capacity. These operations however have a significant impact on the quality of the runoff water from the ditched areas. Peak runoff control (PRC) method has been proposed as a possible method to diminish the load to water courses through retention of the runoff temporarily in the ditch network during maximum runoff events using dams with a plastic control pipe. However, blocking water into the ditched area for periods of varying length during the growing season may have a negative impact on the growth of the tree stands. In this study past stand growth was investigated in Central Finland in altogether 10 sample Scots pine thinning stands in which the PRC method has been applied 5 growing seasons earlier. In each stand, a pair of sample plots was established: one plot next to the dam within the influence of periodic flooding and the other one outside the effect of periodic flooding. For determining stand growth, field measurements were made in August 2009. Stand growth near the dam was on average 0.54 m3 ha-1 a-1 lower than farther away from the dam but the analysis of covariance showed that the dam effect was not significant. The results of this study suggest that the PCR method does not decrease Scots pine stand growth during the first five year growth period after ditch cleaning.
  • Hökkä, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: hannu.hokka@metla.fi (email)
  • Hyttinen, Metsänhoitoyhdistys Keski-Suomi, Viitasaari, Finland ORCID ID:E-mail:
  • Marttila, University of Oulu, Water Resources and Environmental Engineering Lab, Oulu, Finland ORCID ID:E-mail:
  • Jämsen, Forestry Centre Keski-Suomi, Pihtipudas, Finland ORCID ID:E-mail:
  • Kløve, University of Oulu, Water Resources and Environmental Engineering Lab, Oulu, Finland ORCID ID:E-mail:
article id 117, category Research article
Harri Kilpeläinen, Jari Lindblad, Henrik Heräjärvi, Erkki Verkasalo. (2011). Saw log recovery and stem quality of birch from thinnings in southern Finland. Silva Fennica vol. 45 no. 2 article id 117. https://doi.org/10.14214/sf.117
The objective of this study was to examine the timber quality of silver birch (Betula pendula Roth) and European white birch (Betula pubescens Ehrh.) trees in the first and second thinnings in southern parts of Finland, from the viewpoint of sawing of small-diameter, short logs, in particular. The average stem volume of birch was 0.140 m3 in the first thinning stands and 0.206 m3 in the second thinning stands. In planted stands, the trees were larger in the first thinnings but slightly smaller in the second thinnings, compared with naturally regenerated pure birch stands or mixed stands of Norway spruce and birch species. Almost 60% of the harvested and 35% of the remaining stems that could provide saw logs were graded as pulpwood for timber quality due to the occurrence of stem defects. The most common stem defects were multiple crooks and middle crooks. Only minor between-stratum differences were detected in the numbers of defects. Depending on the bucking option, the total percentage of saw and plywood logs from the total birch recovery in the thinning of the sample stands varied between 11.7 and 18.2. The recovery of saw logs was clearly higher in the second thinnings, 12–19%, than in the first thinnings, 8–14%. Of the stand types, saw log recovery was the highest in planted birch stands, 12–19%, but lower in naturally regenerated pure birch stands and mixed stands of Norway spruce and birch. The highest share of saw logs was in the second thinning of planted stands, 17–25%. This study shows that the harvesting recoveries of end-use based timber assortments can be estimated in different kinds of thinning birch stands. Based on tree and log dimensions and stem squality, silver birch firstly from plantations and secondly from mixed stands should be the most interesting source of raw material for the saw milling, furniture and interior product sectors.
  • Kilpeläinen, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Lindblad, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Heräjärvi, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: henrik.herajarvi@metla.fi (email)
  • Verkasalo, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 114, category Research article
Roy V. Rea. (2011). Impacts of moose (Alces alces) browsing on paper birch (Betula papyrifera) morphology and potential timber quality. Silva Fennica vol. 45 no. 2 article id 114. https://doi.org/10.14214/sf.114
Although moose browsing effects on the growth and morphology of birch are well studied, effects of moose browsing on potential timber quality of birch have received little attention. Here, an assessment was made of the impacts of moose (Alces alces L.) damage to Paper Birch (Betula papyrifera Marsh.) trees from a 20-year old clear cut area in a sub-boreal spruce forest within the Aleza Lake Research Forest, near Prince George, British Columbia, Canada. Specifically, differences in overall tree architecture and in the internal characteristics of trees that had been severely damaged and suppressed by moose winter browsing were compared to birch trees that had not been damaged by moose in this way and were considered free-to-grow. The average stem diameter, number of annular growth rings, and height of stem breaks made by moose on suppressed birches at the point of breakage was 17.9 ± 6.6 mm, 4.6 ± 1.2, and 141.8 ± 32.0 cm, respectively. Stem diameters and the heights above-the-ground of stem breaks made by moose during sequential breakage events were not significantly different (all p ≥ 0.05) from one another. Decay was significantly (all p ≤ 0.001) more extensive in trees where branches had been broken off by moose than in trees with no breaks or where breaks were from unknown agents. Suppressed birches were significantly (p = 0.048) more exposed (farther from their nearest tree neighbor) when compared to birches that were free-to-grow. The distance from birch trees to species-specific neighbors (of any species) did not differ (all p ≥ 0.05) between suppressed and free-to-grow birches. Suppressed birches damaged from intense browsing and stem breakage were significantly (≤ 0.001) farther away from other birches showing signs of slight to moderate browsing than free-to-grow birches were from similar conspecifics. Because moose appear to impact the potential wood quality of birch, forest managers should consider the impacts that browsing and stem breakage can have on birch timber where these trees co-occur with and are eaten by moose.
  • Rea, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada V2N 4Z9 ORCID ID:E-mail: reav@unbc.ca (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 157, category Research article
Ville Kankaanhuhta, Timo Saksa, Heikki Smolander. (2010). The effect of quality management on forest regeneration activities in privately-owned forests in southern Finland. Silva Fennica vol. 44 no. 2 article id 157. https://doi.org/10.14214/sf.157
This study describes the effect of quality management on forest regeneration activities in privately-owned forests in southern Finland. The study material consists of two mail surveys conducted in 2006 and 2007. The questionnaires were sent to forestry professionals in Forest Owners’ Associations (FOAs), who had either participated (participants) or not (non-participants) in the forest regeneration quality management interventions in years 2000–2006. Quality management interventions of the FOAs included field inventories, feedback meetings, and education sessions about quality techniques. The activities of participant and non-participant FOAs were compared in terms of the available resources, the actions taken, and the aspirations for improvement. In the FOAs, which had participated in quality management, the number of excavator contractors had increased by 16% more than in the non-participant FOAs. The contractors had acquired 23% more soil preparation equipment under the supervision of the participant forestry professionals. The soil preparation method used in conjunction with Norway spruce that had most increased in use was patch mounding. Seedlings that were 1.5 years and older were used by participant forestry professionals in the planting of Norway spruce 11% more than by non-participants. The planting workers had attended 14% more educational sessions, while the use of self-control measurements in soil preparation and planting density had been adopted 10% more frequently under the supervision of the forestry professionals participating in the quality management. A greater interest in obtaining feedback by using quality control inventories was also found among forestry professionals who participated in quality management.
  • Kankaanhuhta, Finnish Forest Research Institute, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: ville.kankaanhuhta@metla.fi (email)
  • Saksa, Finnish Forest Research Institute, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Smolander, Finnish Forest Research Institute, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 180, category Research article
Hongzhang Kang, Björn Berg, Chunjiang Liu, Carl J. Westman. (2009). Variation in mass-loss rate of foliar litter in relation to climate and litter quality in Eurasian forests: differences among functional groups of litter. Silva Fennica vol. 43 no. 4 article id 180. https://doi.org/10.14214/sf.180
With a data set of litter decomposition collected by means of literature survey, our objectives are 1) to determine the differences in the variation in the first-year mass loss (%) of leaf litter with regard to climate and litter quality among different functional groups of tree species in Eurasian forests, and 2) to determine the difference in effect of mean annual temperature (°C), annual precipitation (dm), as well as concentration of nitrogen (%), and lignin (%) on first-year mass loss over a wide range in climate and litter quality. The main results are as follows. 1) The significant differences between litter types in the relationships between first-year mass loss and climatic factors plus litter quality revealed clearly different decomposition patterns over the continent. Thus, differences were found between coniferous and broadleaf litter, between deciduous broadleaf and evergreen broadleaf as well as between genera and even within a genus, viz. between deciduous and evergreen Quercus. 2) With a change in a relative unit of climate and litter quality variables, there were clear differences in effects of mean annual temperature, annual precipitation, and nitrogen on first-year mass loss for different functional groups of trees. 3) We identified some broadleaf litter species that decomposed to 100% in one year and thus did not contribute to carbon sequestration in a humus layer. Thus, the variation in pattern of foliar litter decomposition with climate and litter quality across functional groups in Eurasian forests showed different decomposition strategies for litter of different groups and genera.
  • Kang, School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240, P. R. China ORCID ID:E-mail:
  • Berg, Department of Forest Ecology, University of Helsinki, Latokartanonkaari 7, FIN-00014 Finland; Dipartimento Biologia Strutturale e Funzionale. Complesso Universitario, Monte S. Angelo, Via Cinthia, IT-80126 Napoli, Italy ORCID ID:E-mail:
  • Liu, School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240, P. R. China; Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, P. R. China, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, P. R. China ORCID ID:E-mail: chjliu@sjtu.edu.cn (email)
  • Westman, Dipartimento Biologia Strutturale e Funzionale. Complesso Universitario, Monte S. Angelo, Via Cinthia, IT-80126 Napoli, Italy ORCID ID:E-mail:
article id 204, category Research article
Gaby Deckmyn, Bostjan Mali, Hojka Kraigher, Niko Torelli, Maarten Op de Beeck, Reinhart Ceulemans. (2009). Using the process-based stand model ANAFORE including Bayesian optimisation to predict wood quality and quantity and their uncertainty in Slovenian beech. Silva Fennica vol. 43 no. 3 article id 204. https://doi.org/10.14214/sf.204
The purpose of this study was to expand an existing semi-mechanistic forest model, ANAFORE (ANAlysing Forest Ecosystems), to allow for the prediction of log quality and the accompanying uncertainty as influenced by climate and management. The forest stand is described as consisting of trees of different cohorts, either of the same or of different species (deciduous or coniferous). In addition to photosynthesis, transpiration, total growth and yield, the model simulates the daily evolution in vessel biomass and radius, parenchyma and branch development. From these data early and latewood biomass, wood tissue composition, knot formation and density are calculated. The new version presented here, includes the description of log quality, including red heart formation of beeches. A Bayesian optimisation routine for the species parameters was added to the stand model. From a given range of input parameters (prior), the model calculates an optimised range for the parameters (posterior) based on given output data, as well as an uncertainty on the predicted values. A case study was performed for Slovenian beech forests to illustrate the main model functioning and more in particular the simulation of the wood quality. The results indicate that the ANAFORE model is a useful tool for analyzing wood quality development and forest ecosystem functioning in response to management, climate and stand characteristics. However, the Bayesian optimization showed that the remaining uncertainty on the input parameters for the chosen stand was very large, due to the large number of input parameters in comparison to the limited stand data.
  • Deckmyn, Research Group Plant and Vegetation Ecology, University of Antwerpen, Universiteitsplein 1, 2610 Antwerpen, Belgium ORCID ID:E-mail: gaby.deckmyn@ua.ac.be (email)
  • Mali, Slovenian Forestry Institute, Vecna pot 2, 1000 Ljubljana, Slovenia ORCID ID:E-mail:
  • Kraigher, Slovenian Forestry Institute, Vecna pot 2, 1000 Ljubljana, Slovenia ORCID ID:E-mail:
  • Torelli, Slovenian Forestry Institute, Vecna pot 2, 1000 Ljubljana, Slovenia ORCID ID:E-mail:
  • Op de Beeck, Research Group Plant and Vegetation Ecology, University of Antwerpen, Universiteitsplein 1, 2610 Antwerpen, Belgium ORCID ID:E-mail:
  • Ceulemans, Research Group Plant and Vegetation Ecology, University of Antwerpen, Universiteitsplein 1, 2610 Antwerpen, Belgium 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 201, category Research article
Rui Qi, Véronique Letort, Mengzhen Kang, Paul-Henry Cournède, Philippe de Reffye, Thierry Fourcaud. (2009). Application of the GreenLab model to simulate and optimize wood production and tree stability: a theoretical study. Silva Fennica vol. 43 no. 3 article id 201. https://doi.org/10.14214/sf.201
The GreenLab model was used to study the interaction between source-sink dynamics at the whole tree level, wood production and distribution within the stem, and tree mechanical stability through simulation and optimization. In this first promising numerical attempt, two GreenLab parameters were considered in order to maximize wood production: the sink strength for cambial growth and a coefficient that determines the way the biomass assigned to cambial growth is allocated to each metamer, through optimization and simulation respectively. The optimization procedure that has been used is based on a heuristic optimization algorithm called Particle Swarm Optimization (PSO). In the first part of the paper, wood production was maximized without considering the effect of wood distribution on tree mechanical stability. Contrary to common idea that increasing sink strength for cambial growth leads to increasing wood production, an optimal value can be found. The optimization results implied that an optimal source and sink balance should be considered to optimize wood production. In a further step, the mechanical stability of trees submitted to their self weight was taken into account based on simplified mechanical assumptions. Simulation results revealed that the allocation of wood at the stem base strongly influenced its global deformation. Such basic mechanical criterion can be an indicator of wood quality if we consider further the active biomechanical processes involved in tree gravitropic responses, e.g. formation of reaction wood.
  • Qi, Ecole Centrale Paris, Laboratory of Applied Mathematics, Grande Voie des Vignes, 92295 Chatenay-Malabry, France; Institute of Automation, Chinese Academy of Sciences, LIAMA/NLPR, P.O.Box 2728, Beijing, China ORCID ID:E-mail: qiruitree@gmail.com (email)
  • Letort, Ecole Centrale Paris, Laboratory of Applied Mathematics, Grande Voie des Vignes, 92295 Chatenay-Malabry, France ORCID ID:E-mail:
  • Kang, Institute of Automation, Chinese Academy of Sciences, LIAMA/NLPR, P.O.Box 2728, Beijing, China ORCID ID:E-mail:
  • Cournède, Ecole Centrale Paris, Laboratory of Applied Mathematics, Grande Voie des Vignes, 92295 Chatenay-Malabry, France; INRIA saclay Ile-de-France, EPI Digiplant, Parc Orsay Université, 91893 Orsay cedex, France ORCID ID:E-mail:
  • Reffye, INRIA saclay Ile-de-France, EPI Digiplant, Parc Orsay Université, 91893 Orsay cedex, France; CIRAD, UMR AMAP, Montpellier, F-34000 France ORCID ID:E-mail:
  • Fourcaud, CIRAD, UMR AMAP, Montpellier, F-34000 France ORCID ID:E-mail:
article id 195, category Research article
John R. Moore, Andrew J. Lyon, Gregory J. Searles, Leena E. Vihermaa. (2009). The effects of site and stand factors on the tree and wood quality of Sitka spruce growing in the United Kingdom. Silva Fennica vol. 43 no. 3 article id 195. https://doi.org/10.14214/sf.195
The extent and sources of variation in the wood quality of Sitka spruce (Picea sitchensis (Bong.) Carr.) were quantified using data collected from 64 stands in northern Britain. These stands were selected on the basis of elevation, latitude, longitude, yield class, initial spacing and the presence or absence of thinning. Dynamic modulus of elasticity (MOE) was calculated from measurements of stress wave velocity made on standing trees and qualitative descriptions were made of stem form. Dynamic MOE of individual trees ranged from 3.81 kN/mm2 up to 12.29 kN/mm2, with a mean of 7.71 kN/mm2. Approximately 55 percent of the variation in dynamic MOE was due to differences between individual trees within a site, while 35 percent was due to differences between sites. The remaining 10 percent was due to differences between the measurements made on opposite sides of each tree. Variation in dynamic MOE at the site level was significantly influenced by yield class, elevation as well as by a number of the interactions between these factors and latitude, longitude and initial spacing. A multiple regression model incorporating these variables was able to explain 45 percent of the variation in dynamic MOE. Ramicorn branches were the most commonly recorded defect (37.2% of all live trees), followed by stem scarring and basal sweep (6.9% and 6.3%, respectively). Dynamic MOE was not influenced by stem straightness (p = 0.10) which indicates the utility of stress wave velocity measurements for segregating Sitka spruce stands based on potential grade recovery.
  • Moore, Centre for Timber Engineering, Napier University, 10 Colinton Road, Edinburgh EH10 5DT, United Kingdom ORCID ID:E-mail: j.moore@napier.ac.uk (email)
  • Lyon, Centre for Timber Engineering, Napier University, 10 Colinton Road, Edinburgh EH10 5DT, United Kingdom ORCID ID:E-mail:
  • Searles, Centre for Timber Engineering, Napier University, 10 Colinton Road, Edinburgh EH10 5DT, United Kingdom ORCID ID:E-mail:
  • Vihermaa, Department of Analytical and Environmental Chemistry, University of Glasgow, Glasgow, UK ORCID ID:E-mail:
article id 217, category Research article
Ville Kankaanhuhta, Timo Saksa, Heikki Smolander. (2009). Variation in the results of Norway spruce planting and Scots pine direct seeding in privately-owned forests in southern Finland. Silva Fennica vol. 43 no. 1 article id 217. https://doi.org/10.14214/sf.217
This study describes the variation in the planting results for 3-year-old Norway spruce (Picea abies (L.) Karst.) and 4-year-old Scots pine (Pinus sylvestris L.) using direct seeding in privately-owned regeneration areas in southern Finland. The study material consists of operative forest regeneration quality management inventory areas from the years 2000–2006. The effect of both the regional and the administrative levels as well as ecological factors was modelled on the basis of the hierarchy structure forestry centre, Forest Owners’ Association (= FOA), forestry professional, regeneration area and sample plot. The major part of the variation occurred at the sample plot and regeneration area level. Particular attention was paid to observation of the clustered spatial distribution of Scots pine seedlings. The FOA and forestry professional levels explained 5% of the variation in Norway spruce planting and 11% of the variation in Scots pine direct seeding. Applied forest regeneration operations, site and soil characteristics were included in the fixed effects. In the planting of Norway spruce the most important factor explaining the regeneration result was soil preparation. Mounding produced better results than patching and disc trenching. The site and soil characteristics were other important factors in the operations. The selection of direct seeding of Scots pine on too fertile, fine textured or moist sites yielded poor results.
  • Kankaanhuhta, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: ville.kankaanhuhta@metla.fi (email)
  • Saksa, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Smolander, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 217, category Research article
Ville Kankaanhuhta, Timo Saksa, Heikki Smolander. (2009). Variation in the results of Norway spruce planting and Scots pine direct seeding in privately-owned forests in southern Finland. Silva Fennica vol. 43 no. 1 article id 217. https://doi.org/10.14214/sf.217
This study describes the variation in the planting results for 3-year-old Norway spruce (Picea abies (L.) Karst.) and 4-year-old Scots pine (Pinus sylvestris L.) using direct seeding in privately-owned regeneration areas in southern Finland. The study material consists of operative forest regeneration quality management inventory areas from the years 2000–2006. The effect of both the regional and the administrative levels as well as ecological factors was modelled on the basis of the hierarchy structure forestry centre, Forest Owners’ Association (= FOA), forestry professional, regeneration area and sample plot. The major part of the variation occurred at the sample plot and regeneration area level. Particular attention was paid to observation of the clustered spatial distribution of Scots pine seedlings. The FOA and forestry professional levels explained 5% of the variation in Norway spruce planting and 11% of the variation in Scots pine direct seeding. Applied forest regeneration operations, site and soil characteristics were included in the fixed effects. In the planting of Norway spruce the most important factor explaining the regeneration result was soil preparation. Mounding produced better results than patching and disc trenching. The site and soil characteristics were other important factors in the operations. The selection of direct seeding of Scots pine on too fertile, fine textured or moist sites yielded poor results.
  • Kankaanhuhta, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: ville.kankaanhuhta@metla.fi (email)
  • Saksa, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Smolander, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 245, category Research article
Saija Huuskonen, Jari Hynynen, Risto Ojansuu. (2008). Stand characteristics and external quality of young Scots pine stands in Finland. Silva Fennica vol. 42 no. 3 article id 245. https://doi.org/10.14214/sf.245
The effects of silvicultural practices (regeneration method and young stand management) on the stand characteristics of young Scots pine (Pinus sylvestris (L.)) stands were studied. Stand density, mean diameter, crown ratio and external quality of young Scots pine stands were analysed on the basis of extensive inventory data. The study material consisted of 181 stands containing inventory growth plots, representing the most common site types for Scots pine and covering all the important wood production areas in Finland. Intensive management practices, i.e. artificial regeneration and precommercial thinning, clearly enhanced mean diameter development of the stand. The overall stand density of the crop trees was relatively low in the material (1925 trees ha–1). In more than one third of the stands, the stem number of crop trees was below 1500 trees ha–1. Stand density was not affected by forest management, but it was slightly higher in Southern than in Northern Finland. The geographical location, in terms of annual effective temperature sum, affected the average slenderness and crown ratio. At a given mean stand diameter, the dominant height of the stand was lower, and the mean crown ratio was higher, in Northern than in Southern Finland. The average external quality of the Scots pine trees was relatively low. The proportion of trees without any observed defects was 54%. The most common external defects were curved stems (23%) and branchiness (9%). Branchiness was more frequent among the largest trees, while curved stems were more common in smaller trees. Defects were the most frequent in planted stands, and in stands growing on fresh sites. The defects were more frequent in Northern Finland than in Southern Finland. The relatively low stand density and poor external quality of the young stands emphasize the importance of stem quality as a tree selection criterion in commercial thinnings of Scots pine stands, if the goal is to produce high quality timber.
  • Huuskonen, University of Helsinki, Department of Forest Ecology, Helsinki, Finland ORCID ID:E-mail: saija.huuskonen@helsinki.fi (email)
  • Hynynen, Finnish Forest Research Institute, Vantaa Research Unit, Vantaa, Finland ORCID ID:E-mail:
  • Ojansuu, Finnish Forest Research Institute, Vantaa Research Unit, Vantaa, Finland ORCID ID:E-mail:
article id 258, category Research article
Ursula Schatz, Henrik Heräjärvi, Kari Kannisto, Matti Rantatalo. (2008). Influence of saw and secateur pruning on stem discolouration, wound cicatrisation and diameter growth of Betula pendula. Silva Fennica vol. 42 no. 2 article id 258. https://doi.org/10.14214/sf.258
The aim of this case study was to compare the impacts of saw and secateur pruning on silver birch (Betula pendula Roth). Data were collected from two saw pruned stands in 2005, and one secateur pruned stand in 2003. All the stands were located in southern Finland. The sample stems were felled, and their butt logs were sawn into flitches, whose knot features and colour defects were measured. In addition, discs were sawn from each stem in order to study the annual ring widths. In this material, pruning with secateurs appeared to cause less colour defects than pruning with a saw. Irrespective of the pruning method used, the colour defects in the stem wood were at their largest in cases where the basal knob or the stem bark appeared to be damaged by pruning. Colour defects spread mainly towards the pith, only in a few cases towards the stem surface. The cicatrisation time of the knots as well as the length of the bark stick remaining inside the stem did not show significant differences between the two pruning methods. Pruning of the lowest living branches appears to have no effect on the diameter growth of silver birch trees.
  • Schatz, Peltotievantie 27, FI-99440 Leppäjärvi, Finland ORCID ID:E-mail:
  • Heräjärvi, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: henrik.herajarvi@metla.fi (email)
  • Kannisto, Finnish Forest Research Institute, Parkano Research Unit, Kaironiementie 54, FI-39700 Parkano, Finland ORCID ID:E-mail:
  • Rantatalo, Peltotievantie 27, FI-99440 Leppäjärvi, Finland ORCID ID:E-mail:
article id 278, category Research article
Katri Luostarinen. (2007). The effect of annual ring orientation and drying method on deformations, casehardening and colour of silver birch (Betula pendula) boards. Silva Fennica vol. 41 no. 4 article id 278. https://doi.org/10.14214/sf.278
Deformations of timber, caused mainly by anisotropic shrinkage, can be partially directed by controlling annual ring orientation through different sawing patterns. Ring orientation also affects the movement of water from within the board to its surface, with rapidity of drying having implications for the wood colour. Here sawn silver birch (Betula pendula Roth) timber was classed into two groups according to ring orientation. Two drying methods were used. The final moisture content was lower and the colour lighter in dried boards with radial than with tangential flats, but deformations were larger in radial than in tangential boards. Both drying and ring orientation affected the final moisture content and moisture gradient of the boards. Very small differences in board sizes or shape had an effect on both colour and deformations. The results support the need for accurate sawing and for classing silver birch timber sawn into parquet billets according to ring orientation in order to optimise the drying quality.
  • Luostarinen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: katri.luostarinen@joensuu.fi (email)
article id 473, category Research article
Ulla Mattila, Tuula Nuutinen. (2007). Assessing the incidence of butt rot in Norway spruce in southern Finland. Silva Fennica vol. 41 no. 1 article id 473. https://doi.org/10.14214/sf.473
The aim of this study was to analyze the occurrence of butt rot damage to Norway spruce in different parts of southern Finland and to quantify the associated loss of quality. The data used in the study are from the 9th National Forest Inventory and consist of 5998 sample plots and 8007 spruce sample trees of saw-timber size. To predict the probability of damage to stands and trees, logistic regression models were constructed. Separate models were made for the whole study area, for the area where the general risk of Heterobasidion root and butt rot damage is high and for the area where the damage frequency is relatively low. In the high-risk area, the probability of damage decreased with increasing elevation and increased with increasing temperature sum. In addition, damage was more common on fertile sites and less common on peatlands; and thick peat layer decreased the risk of damage. The probability of damage was also higher in stands where special or selective cuttings had been carried out. In the sample tree data, the probability of damage increased slightly with increasing diameter and age of the tree. In the low-risk areas, elevation was the only variable that explained the probability of damage to a spruce tree. Site fertility and previous cuttings (more than ten years ago) explained the probability of damage to stands only weakly. For spruce damaged by butt rot, the saw-timber volume was reduced, on average, by 60% both in the high-risk area and in the low-risk area.
  • Mattila, The Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Nuutinen, The Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 319, category Research article
Ulises Diéguez-Aranda, José Antonio Grandas-Arias, Juan Gabriel Álvarez-González, Klaus von Gadow. (2006). Site quality curves for birch stands in north-western Spain. Silva Fennica vol. 40 no. 4 article id 319. https://doi.org/10.14214/sf.319
A model for predicting the height growth of even-aged, birch (Betula pubescens Ehrh.) dominated stands in Galicia (north-western Spain) was developed. Data from stem analysis of 214 trees were used for model construction. Two dynamic site equations derived with the generalized algebraic difference approach (GADA) were tested, which combine compatible site index and height models in one common equation. Both equations are base-age invariant and directly estimate height and site index from any height and age. The fittings were done in one stage using the base-age-invariant dummy variables method. A second-order continuous-time autoregressive error structure was used to correct the inherent autocorrelation of the longitudinal data used in this study. Cieszewski’s model best described the data. This model is therefore recommended for height growth prediction and site classification of birch stands in Galicia.
  • Diéguez-Aranda, Departamento de Ingeniería Agroforestal, Universidad de Santiago de Compostela. Escuela Politécnica Superior, Campus universitario, 27002 Lugo, Spain ORCID ID:E-mail: udieguez@lugo.usc.es (email)
  • Grandas-Arias, Departamento de Ingeniería Agroforestal, Universidad de Santiago de Compostela. Escuela Politécnica Superior, Campus universitario, 27002 Lugo, Spain ORCID ID:E-mail:
  • Álvarez-González, Departamento de Ingeniería Agroforestal, Universidad de Santiago de Compostela. Escuela Politécnica Superior, Campus universitario, 27002 Lugo, Spain ORCID ID:E-mail:
  • Gadow, Institut fur Waldinventur und Waldwachstum, George-Auguts-Universität Göttingen. Büsgenweg 5, D-37077 Göttingen, Germany ORCID ID:E-mail:
article id 375, category Research article
Edgar Víquez, Diego Pérez. (2005). Effect of pruning on tree growth, yield, and wood properties of Tectona grandis plantations in Costa Rica. Silva Fennica vol. 39 no. 3 article id 375. https://doi.org/10.14214/sf.375
Reduced plantation densities have the effect that obtaining natural pruning and stem straightness are less assured. The physiological process of self-pruning is replaced by manual pruning. Generally, plantations are denser and have more uniform spacing than natural forests. In many, if not most species, natural pruning is never a satisfactory option, even after branch senescence, if production of clear wood is a management objective. Natural pruning can only be considered on a species by species basis. This study reports on the first results of a pruning trial for Tectona grandis L.F. plantations in Costa Rica. The treatments consisted of pruning heights of 3.0, 4.0, and 5.0 meters, and the Control without pruning. Differences among treatments in DBH and total height were significant at 3.2, 5.2, and 6.1 years of age, but not at 7.3 years. Under an intensive pruning regime, a teak tree at rotation (20 years) may yield over 40% of knot-free volume (over 60% of the merchantable tree volume). Current findings open a scope for new management options, aiming at improving stem form and wood quality by means of an intensive pruning regime, without having a detrimental effect on tree growth and stand yield.
  • Víquez, Tropical Agricultural Research and Higher Education Center (CATIE), Apartado 7170 CATIE, Turrialba, Costa Rica ORCID ID:E-mail: eviquez@catie.ac.cr (email)
  • Pérez, Ambiente Tierra S.A., Apartado 733-2250, Tres Ríos, Cartago, Costa Rica ORCID ID:E-mail:
article id 371, category Research article
Mika Nieminen, Erkki Ahti, Hannu Nousiainen, Samuli Joensuu, Martti Vuollekoski. (2005). Capacity of riparian buffer zones to reduce sediment concentrations in discharge from peatlands drained for forestry. Silva Fennica vol. 39 no. 3 article id 371. https://doi.org/10.14214/sf.371
In 1995–2001, the efficiency of riparian buffer zone areas to reduce the concentrations of suspended solids in discharge from peatlands drained for forestry purposes was studied at 7 locations in south-central Finland. The two largest buffer zones reduced the concentrations of suspended solids by > 70%. The efficiency of the three medium-sized buffer zones to reduce through-flow sediment concentrations was 50–60%, but no reduction occurred at the smallest two buffer areas. Thus, the capacity of buffer zones to reduce sediment concentrations was strongly related to their size. However, significant correlations were also found between reduction capacity and inflow water sediment concentrations, although the correlations at the two smallest buffer zones were low. The use of buffer zones in reducing sediment load from peatlands drained for forestry purposes is recommended, but relatively large areas for efficient removal capacity are needed.
  • 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)
  • Ahti, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Nousiainen, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Joensuu, Forestry Development Centre Tapio, Soidinkuja 4, FI-00700 Helsinki, Finland ORCID ID:E-mail:
  • Vuollekoski, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 389, category Research article
Ritva Toivonen, Eric Hansen, Erno Järvinen, Raija-Riitta Enroth. (2005). The competitive position of the Nordic wood industry in Germany – intangible quality dimensions. Silva Fennica vol. 39 no. 2 article id 389. https://doi.org/10.14214/sf.389
This study examines the importance of various intangible product quality dimensions as perceived by wood-trading retailer and wholesaler companies in Germany. Using perceived importance and perceived performance, the study first examines the dimensionality of intangible product quality and then compares Nordic wood product suppliers with suppliers from other major supply regions. Data was collected from 76 German companies during 2000–2001. Results indicate that intangible product quality can be described in three dimensions, “Behaviour and Image”, “Serviceability and Environment”, and “Reliability”. Results also show that Nordic suppliers do not have a strong competitive position in Germany in terms of intangible product quality dimensions. Thus, Nordic suppliers could improve their competitive position by enhancing their service, logistics and other dimensions of the intangible product offering.
  • Toivonen, Pellervo Economic Research Institute PTT, Eerikinkatu 28 A, FI-00180, Helsinki, Finland ORCID ID:E-mail: ritva.toivonen@dnainternet.net (email)
  • Hansen, Oregon State University, Dept. of Wood Science & Engineering, Richardson Hall 108, 97331-5751 Corvallis, OR, USA ORCID ID:E-mail:
  • Järvinen, Pellervo Economic Research Institute PTT, Eerikinkatu 28 A, FI-00180, Helsinki, Finland ORCID ID:E-mail:
  • Enroth, Finnish Forest Research Institute, Unioninkatu 40 A, FI-00170 Helsinki, Finland ORCID ID:E-mail:
article id 397, category Research article
Nuutti Kiljunen. (2005). Pricing the risk of the quality-guarantee in a stand establishment service. Silva Fennica vol. 39 no. 1 article id 397. https://doi.org/10.14214/sf.397
A stand-establishment service concept with quality guarantee was analysed. Here, the quality of stand establishment was assessed as the density of good quality seedlings evenly distributed on the plantation three years after planting. The amount of adequate premiums for the guarantee service and the risks accumulating to the service provider were studied. Monte Carlo simulation was used as a tool for analyzing the risks accumulating to the service provider of the stand-establishment in operational environments of different sizes. The premiums calculated to cover the expected amount of claims caused by the plantations not meeting the pre-set criteria were about 4–8% in addition to the approximated costs of stand establishment. The criteria used for determining the success or failure in a stand have a marked effect on the amount of premiums with a reasonable risk of ruin.
  • Kiljunen, Finnish Forest Research Institute, Suonenjoki Research Station, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: nuutti.kiljunen@metla.fi (email)
article id 563, category Research article
Timo Pakkala, Ilkka Hanski, Erkki Tomppo. (2002). Spatial ecology of the three-toed woodpecker in managed forest landscapes. Silva Fennica vol. 36 no. 1 article id 563. https://doi.org/10.14214/sf.563
The effects of landscape structure and forestry on the abundance and dynamics of boreal forest bird species have been studied widely, but there are relatively few studies in which the spatial structure and quality of the landscape have been related to the spatial ecology of bird species. In this paper, we present methods to measure territory and landscape quality for the three-toed woodpecker (Picoides tridactylus) and similar territorial forest bird species based on data from the Finnish multi-source national forest inventory and metapopulation theory. The three-toed woodpecker was studied with territory mapping within an area of 340 square km in southern Finland in 1987–2000. Altogether 195 breeding territory sites were observed. The spatial occurrence of the territories was aggregated, and the highest densities were observed in spruce-dominated old-growth forest areas. Both territory and landscape quality had significant consequences for the occurrence of the three-toed woodpecker. The spatial patterning and permanence of breeding and non-breeding territories were influenced by a combination of spatial dynamics of the species and the quality of the landscape, the latter being much influenced by forestry. The landscape-level spatial occurrence of the three-toed woodpecker in the study area may represent source-sink dynamics. The results of this paper suggest the presence of threshold values at different spatial scales, which may determine the occurrence of the three-toed woodpecker and similar species in managed forest landscapes.
  • Pakkala, Finnish Museum of Natural History, University of Helsinki, P.O. Box 17, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: timo.pakkala@helsinki.fi (email)
  • Hanski, Department of Ecology and Systematics, University of Helsinki, P.O. Box 47, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Tomppo, Finnish Forest Research Institute, Unioninkatu 40 A, FIN-00170 Helsinki, Finland ORCID ID:E-mail:
article id 563, category Research article
Timo Pakkala, Ilkka Hanski, Erkki Tomppo. (2002). Spatial ecology of the three-toed woodpecker in managed forest landscapes. Silva Fennica vol. 36 no. 1 article id 563. https://doi.org/10.14214/sf.563
The effects of landscape structure and forestry on the abundance and dynamics of boreal forest bird species have been studied widely, but there are relatively few studies in which the spatial structure and quality of the landscape have been related to the spatial ecology of bird species. In this paper, we present methods to measure territory and landscape quality for the three-toed woodpecker (Picoides tridactylus) and similar territorial forest bird species based on data from the Finnish multi-source national forest inventory and metapopulation theory. The three-toed woodpecker was studied with territory mapping within an area of 340 square km in southern Finland in 1987–2000. Altogether 195 breeding territory sites were observed. The spatial occurrence of the territories was aggregated, and the highest densities were observed in spruce-dominated old-growth forest areas. Both territory and landscape quality had significant consequences for the occurrence of the three-toed woodpecker. The spatial patterning and permanence of breeding and non-breeding territories were influenced by a combination of spatial dynamics of the species and the quality of the landscape, the latter being much influenced by forestry. The landscape-level spatial occurrence of the three-toed woodpecker in the study area may represent source-sink dynamics. The results of this paper suggest the presence of threshold values at different spatial scales, which may determine the occurrence of the three-toed woodpecker and similar species in managed forest landscapes.
  • Pakkala, Finnish Museum of Natural History, University of Helsinki, P.O. Box 17, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: timo.pakkala@helsinki.fi (email)
  • Hanski, Department of Ecology and Systematics, University of Helsinki, P.O. Box 47, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Tomppo, Finnish Forest Research Institute, Unioninkatu 40 A, FIN-00170 Helsinki, Finland ORCID ID:E-mail:
article id 643, category Research article
Pekka Eskelinen, Harri Eskelinen. (2000). A K-band microwave measuring system for the analysis of tree stems. Silva Fennica vol. 34 no. 1 article id 643. https://doi.org/10.14214/sf.643
The internal structure of growing trees and freshly cut logs can be characterized in real time by analysing the transmission and reflection of Ku- or K-band microwave energy injected with a horizontal polarization towards the material. Information about the moisture content, material bends, number and location of knots and sections of spoiled wood e.g. due to insects can be gathered in real time. Most sensitive test parameters are attenuation, group delay and the rotation of a linearly polarized wavefront. A simultaneous recording of reflection reduces errors caused by non-significant surface deformations. The spatial resolution, humidity equalization and noise immunity can be improved by applying a wideband frequency modulation. Commercial building blocks supplemented with a special antenna arrangement give possibilities also for the rough harvester environment.
  • Eskelinen, Lappeenranta University of Technology, Department of Electrical Engineering, P.O. Box 20, FIN-53851 Lappeenranta, Finland ORCID ID:E-mail: ari.eskelinen@pp.inet.fi (email)
  • Eskelinen, Lappeenranta University of Technology, Department of Electrical Engineering, P.O. Box 20, FIN-53851 Lappeenranta, Finland ORCID ID:E-mail:
article id 663, category Research article
Lennart Moberg. (1999). Variation in knot size of Pinus sylvestris in two initial spacing trials. Silva Fennica vol. 33 no. 2 article id 663. https://doi.org/10.14214/sf.663
The objective of this study was to investigate the variation in internal knot size of Scots pine (Pinus sylvestris L.) stems sampled from mature permanent plots, and for which the silvicultural history was known. It was based on a sample of mature trees removed from two different spacing trials representing a moderate and high site index. Knot size was measured with non-destructive methods using a CT-scanner and digital image analysis. Initial spacing varied between 0.75 and 3 m on the high site-index trial and between 1.5 and 2.5 m on the moderate site-index trial. Wider initial spacing on the high site index resulted in larger knots near the base of the stem. However, due to successive thinnings which gradually equalised stand density among plots, the difference between most plots was less further up in the stems. The effect of silvicultural regime was much more limited on the lower site index. Within-stand differentiation resulted in a variation of tree diameter (DBH); larger trees had significantly larger knots. Furthermore, knots were larger towards south than towards north in both trials. These results illustrated that, by using non-destructive measurements on trees sampled from permanent research plots, it was possible to simultaneously study the variation of internal knot size at stand (such as site and silviculture effects), within-stand (such as relative tree size) and within-tree levels (such as height and azimuth). However, lack of replication prevented valid statistical inference as to stand-level effects.
  • Moberg, Swedish University of Agricultural Sciences, Department of Forest Management and Products, P.O. Box 7060, S-750 07 Uppsala, Sweden ORCID ID:E-mail: lennart.moberg@sh.slu.se (email)
article id 667, category Research article
Timo Kärki. (1999). Predicting the value of grey alder (Alnus incana) logs based on external quality. Silva Fennica vol. 33 no. 1 article id 667. https://doi.org/10.14214/sf.667
The quality of grey alder logs (Alnus incana) was studied by sawing sample logs from two different forests in November 1995–February 1996. For grading of grey alder logs and sawn timber the proposed system of Keinänen and Tahvanainen (1995) plus the reject -grade was used. In general, grey alder logs have knots from the base to the top. All types of knots appear, and the length of the knot-free section is small at the base. In small-dimensioned logs there are fewer knots than in larger logs. Especially in large top logs, there were many more fresh knots than in other types of logs. Evidently, in different types of logs the different grades of sawn timber are located in comparable sections along the length. It also seems that the worse the grade class was, the longer was also the length of the class. The most common reasons for decreasing grade were dry knots and discoloration.
  • Kärki, University of Joensuu, Faculty of Forestry, P.O. BOX 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail: timo.karki@forest.joensuu.fi (email)
article id 667, category Research article
Timo Kärki. (1999). Predicting the value of grey alder (Alnus incana) logs based on external quality. Silva Fennica vol. 33 no. 1 article id 667. https://doi.org/10.14214/sf.667
The quality of grey alder logs (Alnus incana) was studied by sawing sample logs from two different forests in November 1995–February 1996. For grading of grey alder logs and sawn timber the proposed system of Keinänen and Tahvanainen (1995) plus the reject -grade was used. In general, grey alder logs have knots from the base to the top. All types of knots appear, and the length of the knot-free section is small at the base. In small-dimensioned logs there are fewer knots than in larger logs. Especially in large top logs, there were many more fresh knots than in other types of logs. Evidently, in different types of logs the different grades of sawn timber are located in comparable sections along the length. It also seems that the worse the grade class was, the longer was also the length of the class. The most common reasons for decreasing grade were dry knots and discoloration.
  • Kärki, University of Joensuu, Faculty of Forestry, P.O. BOX 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail: timo.karki@forest.joensuu.fi (email)

Category: Research note

article id 7798, category Research note
Jānis Liepiņš, Jānis Ivanovs, Andis Lazdiņš, Jurģis Jansons, Kaspars Liepiņš. (2017). Mapping of basic density within European aspen stems in Latvia. Silva Fennica vol. 51 no. 5 article id 7798. https://doi.org/10.14214/sf.7798
Highlights: Stem bark is significantly denser than wood and does not follow the same variation patterns along the stem; The main trend in radial variation of wood density was the increase from pith to bark; There is a weak relationship between mean basic density and commonly measured stand and tree parameters.

The objective of this study was to investigate basic density and its within-stem variation by studying 84 European aspen stems from 28 forest stands in Latvia. The studied forest stands covered all age classes from young stands to matured forests in representative growth conditions of European aspen. The densities of 2722 wood and 1022 bark specimens were measured from the sampled trees. Only the knot-free wood specimens without obvious wood defects were chosen for analyses. A map of basic density summarizing its radial and axial variations was constructed to show species-specific, within-stem variability and the relationships between density and tree and stand variables were examined. Stem wood and bark of the European aspen show different patterns of basic density variation along the tree stem. Wood density increases from pith to bark up to certain dimensions and shows a slight decrease afterwards. The weighted basic density of bark (446 ± 39.6 kg m–3) was higher than stem wood density (393 ± 30.4 kg m–3). Our results suggest that wood and bark density measurements obtained at breast height can be used for reliable estimation of the densities of whole-tree stem components, while tree parameters such as diameter at breast height (DBH), tree height and social status or stand parameters, including number of trees, basal area and age, are weak predictors in this context.

  • Liepiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: janis.liepins@silava.lv (email)
  • Ivanovs, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: janis.ivanovs@silava.lv
  • Lazdiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: andis.lazdins@silava.lv
  • Jansons, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: jurgis.jansons@silava.lv
  • Liepiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: kaspars.liepins@silava.lv
article id 1026, category Research note
Leif Nutto, Ricardo A. Malinovski, Martin Brunsmeier, Felipe Schumacher Sant’Anna. (2013). Ergonomic aspects and productivity of different pruning tools for a first pruning lift of Eucalyptus grandis Hill ex Maiden. Silva Fennica vol. 47 no. 4 article id 1026. https://doi.org/10.14214/sf.1026
Highlights: Pruning of hardwoods coming from forest plantations is becoming more and more important in Brazil to replace scarce wood from tropical forests; Evaluating productivity of different pruning tools is essential for the economic output of plantations managed for high quality wood; Pruning activities of forest workers can be classified as “hard” or “very hard work”. Depending on the tools used physical long-term damages may be prevented.
For the substitution of wood from tropical rainforests pruning of Eucalyptus for producing valuable hardwoods in short rotation plantations has become important. Existing tools and ergonomic aspects of pruning were not yet well analysed under these conditions. The objective of the study is to evaluate the productivity and ergonomics of three different pruning tools in a pruning lift up to 3 m in height. The trees used in the study came from an 18-month-old clonal Eucalyptus grandis stand planted in a 5.0 x 2.8 m spacing. Two manual pruning tools and an electric shear were tested for productivity by using time studies. Ergonomic aspects were evaluated by two test persons using pulse meter equipment. The highest productivity could be shown for the electric shear (236 trees per working day), followed by the manual shear (196 trees/day) and the handsaw (180 trees/day). The heartbeat rate of the two test persons ranged from a level of “very hard work” for the manual tools to “middle hard” and “hard work” for the electric shear. The workload level to achieve the productivity currently reached in practice using purely manual tools is extremely high, exceeding the permanent working capacity of the operators and leading to physical degradation on the long run.
  • Nutto, Department for Forestry, Federal University of Paraná, Av. Pref. Lothário Meissner, 632, Curitiba, PR, Brazil ORCID ID:E-mail: lnutto.ufpr@gmail.com (email)
  • Malinovski, Department for Forestry, Laboratory of Forest Operations, Federal University of Paraná, Av. Prefeito Lothario Meissner, 900, Curitiba, PR, Brazil ORCID ID:E-mail: ricardo@colheitademadeira.com.br
  • Brunsmeier, Chair of Forest Utilization, University of Freiburg, Werthmannstraße 6, 79085 Freiburg, Germany ORCID ID:E-mail: martin.brunsmeier@fobawi.uni-freiburg.de
  • Schumacher Sant’Anna, Department for Forestry, Laboratory of Forest Operations, Federal University of Paraná, Av. Prefeito Lothario Meissner, 900, Curitiba, PR, Brazil ORCID ID:E-mail: felipe@colheitademadeira.com.br
article id 659, category Research note
Anneli Viherä-Aarnio, Pirkko Velling. (1999). Growth and stem quality of mature birches in a combined species and progeny trial. Silva Fennica vol. 33 no. 3 article id 659. https://doi.org/10.14214/sf.659
The growth and stem quality of silver birch (Betula pendula), downy birch (B. pubescens) and paper birch (B. papyrifera) were compared in a 32-year-old field trial in southern Finland. The material consisted of different unselected stand origins and progenies of phenotypically selected plus trees of silver and downy birch from southern Finland and differing stand origins of paper birch from the North-West Territories, Canada. Growth, yield and a number of stem quality traits, including taper, sweep, stem defects, heights of different crown limits and length of the veneer timber part of the stem were measured or observed. The native Finnish silver and downy birches were superior to paper birch in terms of both yield and stem quality, silver birch being the best. Progenies of silver birch plus trees were better than the stand origin, indicating that the former are able to reach high quality veneer log size in a shorter time than unselected material. The cultivation of paper birch can not be considered viable in Finland.
  • Viherä-Aarnio, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: anneli.vihera-aarnio@metla.fi (email)
  • Velling, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:

Category: Article

article id 7167, category Article
Veijo Heiskanen. (1966). Tutkimuksia rauduskoivikon karsimisen kannattavuudesta. Acta Forestalia Fennica vol. 81 no. 2 article id 7167. https://doi.org/10.14214/aff.7167
English title: Studies on the profitability of pruning of common birch (Betula pendula) stands.

The objective of the present investigation was to clarify the profitability of pruning silver birch (Betula verrucosa, now Betula pendula Roth) in the growing of raw material for veneer industry. Calculations were made on the grade, value, and price of pruned and untreated butt logs as well as on costs of pruning and the development of pruned trees.

The grade distribution of unpruned veneer butt logs, the grade distribution of the veneer yield, and consequently, the value of veneer yield and log prices at the plant are considerably better than those of average logs. The grade, value and price increased with increasing diameter. The value and price of pruned butt logs depended primarily on the difference between the turning pruning diameters, and their increase with decreasing pruning diameter and increasing turning diameter. The value of pruned butt logs is always considerably higher than that of unpruned logs. The increase in the value correlates to the pruning and turning diameters, and is, for example, in rotary-cut logs which have been pruned when 10 cm in diameter 80–130%.

Pruning increases the stumpage in naturally regenerated silver birch stands on Oxalis-Myrtillus site by 2,000–3,000 Fmk/ha when employed at 20 years of stand age and rotary cutting at 60–80 years of age respectively. The average pruning costs on Oxalis-Myrtillus site are 51–57 Fmk/ha.

The PDF includes a summary English.

  • Heiskanen, ORCID ID:E-mail:
article id 7167, category Article
Veijo Heiskanen. (1966). Tutkimuksia rauduskoivikon karsimisen kannattavuudesta. Acta Forestalia Fennica vol. 81 no. 2 article id 7167. https://doi.org/10.14214/aff.7167
English title: Studies on the profitability of pruning of common birch (Betula pendula) stands.

The objective of the present investigation was to clarify the profitability of pruning silver birch (Betula verrucosa, now Betula pendula Roth) in the growing of raw material for veneer industry. Calculations were made on the grade, value, and price of pruned and untreated butt logs as well as on costs of pruning and the development of pruned trees.

The grade distribution of unpruned veneer butt logs, the grade distribution of the veneer yield, and consequently, the value of veneer yield and log prices at the plant are considerably better than those of average logs. The grade, value and price increased with increasing diameter. The value and price of pruned butt logs depended primarily on the difference between the turning pruning diameters, and their increase with decreasing pruning diameter and increasing turning diameter. The value of pruned butt logs is always considerably higher than that of unpruned logs. The increase in the value correlates to the pruning and turning diameters, and is, for example, in rotary-cut logs which have been pruned when 10 cm in diameter 80–130%.

Pruning increases the stumpage in naturally regenerated silver birch stands on Oxalis-Myrtillus site by 2,000–3,000 Fmk/ha when employed at 20 years of stand age and rotary cutting at 60–80 years of age respectively. The average pruning costs on Oxalis-Myrtillus site are 51–57 Fmk/ha.

The PDF includes a summary English.

  • Heiskanen, ORCID ID:E-mail:
article id 7165, category Article
Veijo Heiskanen. (1966). Tutkimuksia koivujen vikaisuuksista, niiden vaikutuksesta sorvaustulokseen sekä niiden huomioonottamisesta laatuluokituksessa. Acta Forestalia Fennica vol. 80 no. 3 article id 7165. https://doi.org/10.14214/aff.7165
English title: Studies on the defects of birch, their influence on the quality and quantity of rotary cut veneer, and their consideration in veneer birch grading.

The objective of this paper was to study the influence of defects of Betula pendula Roth and Betula pubescens Ehrh. on the quality, value and quantity of veneer cut produced by rotary cutting, to prepare grading rules for veneer birch and to determine the minimum quality for veneer birch, and to assess the quality and quantity of veneer yield in rotary cutting of bolts of different grades. Data for the study was collected in 1953-1963 from six plywood factories in Finland.

The effect of knot marks, knot bumps, dry and rotten knots, sound knots, sweep and crookedness, upright limbs, heart rot, open and overgrown scars and bark peeling defects in the bolt on the quality and yield of veneer is described. Recommendations for grading rules were defined on the basis of the result. The rules include three grades, for which certain defects are allowed. In the first grade are accepted bolts, which of the veneer yield included at least 30% of veneer of grades A and B when all jointing and end-clipped sheets were taken into account. In the second grade were accepted bolts, which of the main part of the veneer yield still is surface veneer on the basis of the wood quality. Of the third-grade bolts at least one third of the veneer yield ought to be surface veneer.

The PDF includes a summary in English.

  • Heiskanen, ORCID ID:E-mail:
article id 7164, category Article
Veijo Heiskanen. (1965). Puiden paksuuden ja nuoruuden kehityksen sekä oksaisuuden ja sahapuulaadun välisistä suhteista männiköissä. Acta Forestalia Fennica vol. 80 no. 2 article id 7164. https://doi.org/10.14214/aff.7164
English title: Relation between the development of the early age and thickness of trees and their branchiness in Scots pine stands in Finland.

The objective of the study was to establish the influence of the founding density of a stand and the intensity of intermediate cutting on the quality of pine saw logs stems, primarily on their branchiness. Measurements were carried out in 68 Myrtillus-type and 32 Vaccinium-type Scots pine (Pinus sylvestris L.) stands. The quality of 1,982 sample trees was assessed.

According to the results, the branchless part of the stem is longest in the older age classes of trees. In all age classes the percentage of the branchless part is highest in medium sized stems. The relative height of the crown limit is greatest in small diameter classes and continues as the thickness of the tree increases. The crown is longer in the thicker tree. The grade of the butt log is on average highest in medium sized stems. Knottiness of a log made it unsuitable for a saw log only among the thickest stems. The relative share of the u/s grade decreased as the thickness of the trees increased.

From the point of view of early development of the trees it was concluded that in all age classes the branchless part is the shorter the faster the tree has grown in diameter when it was young. Also, branches of the butt log are the bigger the faster the tree has developed when it was young. The grade of the butt log improves as the thickness of the annual rings diminishes.

To produce good quality sawn timber, the pine stands should be established dense, and the first thinnings should be delayed as much as possible. The best time for the thinning would be when the diameter of the dominant trees at stump height is 12–15 cm and when all the branches have died on the length of the butt log. After the first thinning, comparatively intense intermediate thinning may be applied.

The PDF includes a summary in English.

  • Heiskanen, ORCID ID:E-mail:
article id 7164, category Article
Veijo Heiskanen. (1965). Puiden paksuuden ja nuoruuden kehityksen sekä oksaisuuden ja sahapuulaadun välisistä suhteista männiköissä. Acta Forestalia Fennica vol. 80 no. 2 article id 7164. https://doi.org/10.14214/aff.7164
English title: Relation between the development of the early age and thickness of trees and their branchiness in Scots pine stands in Finland.

The objective of the study was to establish the influence of the founding density of a stand and the intensity of intermediate cutting on the quality of pine saw logs stems, primarily on their branchiness. Measurements were carried out in 68 Myrtillus-type and 32 Vaccinium-type Scots pine (Pinus sylvestris L.) stands. The quality of 1,982 sample trees was assessed.

According to the results, the branchless part of the stem is longest in the older age classes of trees. In all age classes the percentage of the branchless part is highest in medium sized stems. The relative height of the crown limit is greatest in small diameter classes and continues as the thickness of the tree increases. The crown is longer in the thicker tree. The grade of the butt log is on average highest in medium sized stems. Knottiness of a log made it unsuitable for a saw log only among the thickest stems. The relative share of the u/s grade decreased as the thickness of the trees increased.

From the point of view of early development of the trees it was concluded that in all age classes the branchless part is the shorter the faster the tree has grown in diameter when it was young. Also, branches of the butt log are the bigger the faster the tree has developed when it was young. The grade of the butt log improves as the thickness of the annual rings diminishes.

To produce good quality sawn timber, the pine stands should be established dense, and the first thinnings should be delayed as much as possible. The best time for the thinning would be when the diameter of the dominant trees at stump height is 12–15 cm and when all the branches have died on the length of the butt log. After the first thinning, comparatively intense intermediate thinning may be applied.

The PDF includes a summary in English.

  • Heiskanen, ORCID ID:E-mail:
article id 7163, category Article
Jaakko Meriluoto. (1965). Raaka-ainetekijöiden vaikutus sorvatun koivuviilun määrään ja laatuun. Acta Forestalia Fennica vol. 80 no. 1 article id 7163. https://doi.org/10.14214/aff.7163
English title: The influence of raw material factors on the quantity and quality of rotary cut birch veneer.

The objective of the present investigation was to clarify the influence of raw material on the quantity, and especially quality of rotary cut birch veneer by running cutting tests with constant tool setting under factory conditions and with bolts of normal size. The quality of the veneer was mainly examined in laboratory.

The result showed that with an increase in bolt size the yield increases and reaches the maximal value in the diameter range of 251–275 mm and 226–250 mm for 60-inch and 50-inch bolt, respectively. With a decrease in bolt length the yield becomes higher. With the increase in the bolt size the quality of the veneer improves.

Defects in the shape of the bolt, such as crookedness, taper and oval form, decrease the yield. The good quality of the bolts affects most the yield of full-size sheets. Increase of knottiness decreases the yield by 4–5%. Lowering of the bolt temperature below 0 °C causes a sharp decline in the yield. Moisture content of the wood did not markedly affect the yield, but it improved the quality of the veneer. The minimum moisture content was 75%.

For the technical quality of the veneer, bolt temperature was the most decisive raw material factor. Also shape defects, of which crookedness was most serious, decreased the technical quality. Increase in summerwood percentage improved the quality.

The PDF includes a summary in English.

  • Meriluoto, ORCID ID:E-mail:
article id 7157, category Article
Leo Heikurainen, Kustaa Seppälä. (1965). Regionality in stand increment and its dependence on the temperature factor on drained swamps. Acta Forestalia Fennica vol. 78 no. 4 article id 7157. https://doi.org/10.14214/aff.7157

The aim of this work was to study, on the basis of material published earlier (Heikurainen 1959), the effect of temperature on stand increment, to find out if there is any differences between Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.), and to study the effect of site quality on the relationship between stand increment and temperature. The calculations were based on data collected from 396 sample plots on drained peatlands in different parts of Finland.

There seemed to be no differences due to tree species or site quality in the relative amounts of growth under different climatic conditions. Thus, differences in the absolute growth between poor and fertile sites are noticeably smaller in Northern Finland than in Southern Finland. The author suggests that this implies that the lasting maximal increase of growth which can be produced, for instance, by using soil-improving agents must be less in unfavourable conditions than in favourable.

  • Heikurainen, ORCID ID:E-mail:
  • Seppälä, ORCID ID:E-mail:
article id 7400, category Article
P. S. Tikka. (1949). Perä-Pohjolan koivikoiden laadusta. Acta Forestalia Fennica vol. 57 no. 4 article id 7400. https://doi.org/10.14214/aff.7400
English title: Quality of birch (Betula sp.) stands in the northernmost Finland.

The quality of birch (Betula sp.) stands in Perä-Pohjola in Northern Finland is low due to the harsh environment, unsuitable sites for the species and unsatisfactory silvicultural state. A total of 236 sample trees were felled and measured in 8 sample plots. The trees were over 80 years old.

Only third of the stand volume of birch in the stands had adequate quality for merchantable timber. This is due to birch growing often in sites unsuitable for the species, the low density of the stands, the small average size of stems, and the low amount of large sized trees. These problems may contribute to the fact that birch seem to be susceptible to decay. The trees have often grown from sprouts, which leads often to poor stem form and decay. The volume and quality of both pure and mixed birch stands was sufficient only in the most fertile sites. Also, decay was more common in poor sites.

The PDF includes a summary in German.

  • Tikka, ORCID ID:E-mail:
article id 7400, category Article
P. S. Tikka. (1949). Perä-Pohjolan koivikoiden laadusta. Acta Forestalia Fennica vol. 57 no. 4 article id 7400. https://doi.org/10.14214/aff.7400
English title: Quality of birch (Betula sp.) stands in the northernmost Finland.

The quality of birch (Betula sp.) stands in Perä-Pohjola in Northern Finland is low due to the harsh environment, unsuitable sites for the species and unsatisfactory silvicultural state. A total of 236 sample trees were felled and measured in 8 sample plots. The trees were over 80 years old.

Only third of the stand volume of birch in the stands had adequate quality for merchantable timber. This is due to birch growing often in sites unsuitable for the species, the low density of the stands, the small average size of stems, and the low amount of large sized trees. These problems may contribute to the fact that birch seem to be susceptible to decay. The trees have often grown from sprouts, which leads often to poor stem form and decay. The volume and quality of both pure and mixed birch stands was sufficient only in the most fertile sites. Also, decay was more common in poor sites.

The PDF includes a summary in German.

  • Tikka, ORCID ID:E-mail:
article id 7389, category Article
P. S. Tikka. (1947). Perä-Pohjolan kuusikoiden laadusta. Acta Forestalia Fennica vol. 55 no. 1 article id 7389. https://doi.org/10.14214/aff.7389
English title: Quality of Norway spruce stands in Peräpohjola in Northern Finland.

The different kinds of injuries in Norway spruce (Picea abies (L.) Karst.) stands was studied in 52 sample plots in Peräpohjola in the northernmost Finland. The age classes of the stands varied from 100 years to over 220 years. Most of the stands were unevenaged, as is usual in the area.

In the younger age classes (121-160 years) majority of the trees were of normal quality or had smaller injuries in all forest types. In age classes over 160 years the trees of merchantable quality decreased markedly in all forest types. The quality of the trees decreases with the age especially because of butt rot, braking of trees and crooks, forks and heart and top decay caused by the injuries. To ensure future quality it would be important that the stand is healthy from the beginning. When old spruce stands of the area are in large extent diseased by the root rot, it is questionable if they can be regenerated using natural regeneration. The spruce stands of the area are also relatively branchy. This could be prevented by growing the young stands dense. Changing the dominant tree species to Scots pine (Pinus sylvestris L.) in the dry upland forest sites could be a way to improve the quality of the forests in the area.

The PDF includes a summary in German.

  • Tikka, ORCID ID:E-mail:
article id 7346, category Article
Th. Wegelius. (1939). The presence and properties of knots in finnish spruce : investigations concerning the origin and characteristics of branch and knot wood in finnish spruce with particular consideration given to the raw material needs of the paper industry. Acta Forestalia Fennica vol. 48 no. 1 article id 7346. https://doi.org/10.14214/aff.7346

The most important characteristics for the quality of round timber is knottiness. Knots decrease the strength of the wood in sawn goods. Knots in pulpwood obstruct the production process of ground pulp and lower the quality. A qualitative classification of saw logs has been suggested, and the abundance of knots could also be used to determine the quality of pulpwood. In this study, visual observations on the preparation of pulpwood in pulp mill were made to observe the quality of the wood. Samples of the wood was collected, and they were divided in five quality classes. To study the influence of age, forest site type and stand on knots, 140 sample trees of Norway spruce (Picea abies (L.) H. Karst.) were analyzed. The article includes detailed analysis of the abundance and position of knots in the stems of spruce, anatomical structure of the knots, microscopic structure of the fibers, and mechanical properties of the branch and knot wood.

  • Wegelius, ORCID ID:E-mail:
article id 7317, category Article
Erkki Laitakari. (1935). Tutkimuksia metsikön ja kasvupaikan vaikutuksesta kuusen rungon kelpoisuuteen. Acta Forestalia Fennica vol. 41 no. 4 article id 7317. https://doi.org/10.14214/aff.7317
English title: Studies on the influence of stand and forest site type on the quality of Norway spruce stem.

Healthy, straight, more or less free from branches and slowly tapering stems are good raw material for woodworking industry. The aim of the study was to investigate, from the stand point of forest management, the influence of stand and forest site type on the technical quality of the stems. Sample plots were measured in Norway spruce (Picea abies (L.) H. Karst.) stands in Eastern Finland. Norway spruce growing in a stand with closed crowns developed thin branches and self-pruned, if the stand was dense in the early stages. The decisive time for the stand is, therefore, when it is at seedling stage and young stand. The stems are more branchy if the stand has been planted. The adequate planting density is discussed based on earlier studies. The sufficient density seems to be achieved when the spacing is at maximum two meters. When the stems are branchless up to four meters, thinning of spruce stand does not affect knottiness or stem form. A sparsely stocked, knotty young stand does not produce good-quality timber even if the stand is later dense. Selective thinning from above can be used to improve the quality of the wood.

The PDF includes a summary in German.

  • Laitakari, ORCID ID:E-mail:
article id 7317, category Article
Erkki Laitakari. (1935). Tutkimuksia metsikön ja kasvupaikan vaikutuksesta kuusen rungon kelpoisuuteen. Acta Forestalia Fennica vol. 41 no. 4 article id 7317. https://doi.org/10.14214/aff.7317
English title: Studies on the influence of stand and forest site type on the quality of Norway spruce stem.

Healthy, straight, more or less free from branches and slowly tapering stems are good raw material for woodworking industry. The aim of the study was to investigate, from the stand point of forest management, the influence of stand and forest site type on the technical quality of the stems. Sample plots were measured in Norway spruce (Picea abies (L.) H. Karst.) stands in Eastern Finland. Norway spruce growing in a stand with closed crowns developed thin branches and self-pruned, if the stand was dense in the early stages. The decisive time for the stand is, therefore, when it is at seedling stage and young stand. The stems are more branchy if the stand has been planted. The adequate planting density is discussed based on earlier studies. The sufficient density seems to be achieved when the spacing is at maximum two meters. When the stems are branchless up to four meters, thinning of spruce stand does not affect knottiness or stem form. A sparsely stocked, knotty young stand does not produce good-quality timber even if the stand is later dense. Selective thinning from above can be used to improve the quality of the wood.

The PDF includes a summary in German.

  • Laitakari, ORCID ID:E-mail:
article id 7302, category Article
M. Lappi-Seppälä. (1934). Karsimisesta ja sen metsänhoidollisesta merkityksestä. Acta Forestalia Fennica vol. 40 no. 25 article id 7302. https://doi.org/10.14214/aff.7302
English title: The silvicultural influences of pruning.

Pruning growing trees influences tree growth and value of the wood and yield of timber of the stand. Pruning living branches create open wounds on the stems that can risk the growth of tree species that are vulnerable to injuries. For instance, pruning has been shown to cause decay in Norway spruce (Picea abies (L.) H. Karst.), while Scots pine (Pinus sylvestris L.) can quickly heal over the branch scars. Pruning of living branches reduces the crown, the effect of which remains small if only the lowest branches are pruned. Pruning of dry branches has little effect on the health of the tree. The main objective of pruning is to improve the quality of timber. Knottiness decreases strength and appearance of timber. Pruning increases the yield of knot-free sapwood, which is especially valuable in veneer timber. Pruning is, therefore, at present most suitable for birch and aspen which are used in veneer industry. In both species pruning should be directed mainly to dry branches.

The PDF includes a summary in German.

  • Lappi-Seppälä, ORCID ID:E-mail:
article id 7296, category Article
T. Rancken. (1934). Erfarenheter om asken som skogsträd i Finland. Acta Forestalia Fennica vol. 40 no. 19 article id 7296. https://doi.org/10.14214/aff.7296
English title: Experiences of cultivation of ash as a forest tree in Finland.

Cultivation of ash (Fraxinus exelsior L.), even though it is a native species in Finland, has been hindered by the belief that it cannot produce quality timber in Finland. However, it can be concluded that the quality of ash timber is as good as that of timber imported to the country, if the trees are grown in a fertile site, the crown density is high, and the stand is tended properly. In these conditions, ash wood may have 3 mm ring width or more. Measurements made in ash stands in Turku region and in Åland show that at the best sites ash trees reach a height of 20–22 m in 70–80 years. According to the field tests made by the author, it can be concluded that ash can be successfully grown in Southern Finland in Åland, Turku region, in the coastal areas of Uusimaa and in Karelian isthmus. The species requires a fertile, moist upland forest site. The early growth is best secured by planting the seedlings under a well thinned broadleaved stand, which is then thinned every fifth year. Open lands growing grass should be avoided.

The PDF includes a Finnish and German summary.

  • Rancken, ORCID ID:E-mail:
article id 7263, category Article
I. Lassila. (1931). Untersuchungen über den Einfluss des Waldtyps auf die Qualität der Kiefer. Acta Forestalia Fennica vol. 37 no. 1 article id 7263. https://doi.org/10.14214/aff.7263
English title: Studies on the influence of the forest type on the quality of pine.

The quality of timber is very important in trade and dependable on the purpose of the timber. The article describes the influence of the forest type on the mechanic-technical properties of the timber. The studied properties are weight, the mean breadth of the annual growth rings, and the compression strength.

The percentage of the annual growth rings that is formed during the autumn is characteristic for the compression strength, and it varies accordingly on different forest types. The result from the formula of Janka depends on the forest type.

Being able to classify the timber according its quality makes it possible to have better price for it. it is also important when deciding for what purpose the timber can be used.

The PDF contains a summary in Finnish. 

  • Lassila, ORCID ID:E-mail:
article id 5635, category Article
Tommi Ruha, Martti Varmola. (1997). Precommercial thinning in naturally regenerated Scots pine stands in northern Finland. Silva Fennica vol. 31 no. 4 article id 5635. https://doi.org/10.14214/sf.a8537

The effects of precommercial thinning on the quantity and external quality of young Scots pine (Pinus sylvestris L.) stands were examined over two 10-year periods in an experiment comprising five stands growing on sub-dry sites in Finnish Lapland, northern Finland. The thinning treatments applied resulted in stand densities of 625, 1111, 1600, 2500 and 4444 stems ha-1 and a no-treatment, unthinned plot with a randomised block lay-out of two or three replications in each stand. The dominant height of the stands varied between 4 and 8 m at the time of thinning.

The trees reacted only slightly to the increase in growing space during the first ten years following precommercial thinning. During the second 10-year period, increased growing space was reflected more clearly in diameter and volume increment. These reactions were more evident in stands thinned at an early stage. The increment of the thinnest 100–200 trees ha-1 in each treatment was poor. The results showed that when the main principle in precommercial thinning is to achieve even spacing, the remaining smallest trees fail to react positively to the increase in growing space. In other words, the target of precommercial thinning should be to concentrate the increment on the tallest trees, even though they are located in groups. The external quality of the trees in stands where precommercial thinning was carried out at a later stage was high, and the diameter of the thickest branch along the butt log remained under 20 mm. Branch diameter was greater in stands thinned at an early stage. The effect of precommercial thinning on branch diameter when comparing the extreme treatments averaged 5 mm. When the aim of stand management is to combine high quality and good yield in naturally regenerated Scots pine stands in northern Finland, precommercial thinning should not be carried out before the dominant height of 7–8 m. The intensity of precommercial thinning depends on the yield targets of the first commercial thinning. A spacing of 2,500 stems ha-1 satisfies the requirements of both high quality and adequate yield.

  • Ruha, ORCID ID:E-mail:
  • Varmola, ORCID ID:E-mail:
article id 5632, category Article
Annikki Mäkelä, Veli-Pekka Ikonen, Petteri Vanninen. (1997). An application of process-based modelling to the development of branchiness in Scots pine. Silva Fennica vol. 31 no. 3 article id 5632. https://doi.org/10.14214/sf.a8534

A process-oriented tree and stand growth model is extended to be applicable to the analysis of timber quality, and how it is influenced by silvicultural treatments. The tree-level model is based on the carbon balance and it incorporates the dynamics of five biomass variables as well as tree height, crown base, and breast height diameter. Allocation of carbon is based on the conservation of structural relationships, in particular, the pipe model. The pipe-model relationships are extended to the whorl level, but in order to avoid a 3-dimensional model of entire crown structure, the branch module is largely stochastic and aggregated. In model construction, a top-down hierarchy is used where at each step down, the upper level sets constraints for the lower level. Some advantages of this approach are model consistency and efficiency of calculations, but probably at the cost of reduced flexibility. The detailed structure related with the branching module is preliminary and will be improved when more data becomes available. Model parameters are identified for Scots pine (Pinus sylvestris L.) in Southern Finland, and example simulations are carried out to compare the development of quality characteristics in different stocking densities.

  • Mäkelä, ORCID ID:E-mail:
  • Ikonen, ORCID ID:E-mail:
  • Vanninen, ORCID ID:E-mail:
article id 5616, category Article
Hannu Hökkä, Virpi Alenius, Timo Penttilä. (1997). Individual-tree basal area growth models for Scots pine, pubescent birch and Norway spruce on drained peatlands in Finland. Silva Fennica vol. 31 no. 2 article id 5616. https://doi.org/10.14214/sf.a8517

Models for individual-tree basal area growth were constructed for Scots pine (Pinus sylvestris L.), pubescent birch (Betula pubescens Ehrh.) and Norway spruce (Picea abies (L.) Karst.) growing in drained peatland stands. The data consisted of two separate sets of permanent sample plots forming a large sample of drained peatland stands in Finland. The dependent variable in all models was the 5-year basal area growth of a tree. The independent tree-level variables were tree dbh, tree basal area, and the sum of the basal area of trees larger than the target tree. Independent stand-level variables were stand basal area, the diameter of the tree of median basal area, and temperature sum. Categorical variables describing the site quality, as well as the condition and age of drainage, were used. Differences in tree growth were used as criteria in reclassifying the a priori site types into new yield classes by tree species. All models were constructed as mixed linear models with a random stand effect. The models were tested against the modelling data and against independent data sets.

  • Hökkä, ORCID ID:E-mail:
  • Alenius, ORCID ID:E-mail:
  • Penttilä, ORCID ID:E-mail:
article id 5605, category Article
Matti Haapanen, Marja-Leena Annala, Pirkko Velling. (1997). Progeny trial estimates of genetic parameters for growth and quality traits in Scots pine. Silva Fennica vol. 31 no. 1 article id 5605. https://doi.org/10.14214/sf.a8506

Estimates of individual heritability and genetic correlation are presented for a set of 10 growth and quality traits based on data from 16 Scots pine (Pinus sylvestris L.) progeny trials in Finland. Seven of the traits (tree height, stem diameter, crown width, Pilodyn value, branch diameter, branch angle and branch number) were objectively measured, whereas three traits (stem straightness, branching score and overall score) were assessed visually. The genetic correlations were mostly moderate or low, and favourable from the tree breeder's point of view. All variables related to tree size correlated relatively strongly and positively. Tree height exhibited a more favourable genetic relationship with the crown form traits than diameter, the latter showing positive correlation with branch diameter. Except for the slight negative correlation between branch angle and branch diameter, the branching traits were not notably correlated. The pilodyn value was positively correlated with stem diameter, reflecting negative correlation between diameter growth and wood density. The highest genetic correlations occurred among the two visually evaluated quality scores and branch diameter. All of the heritabilities were less than 0.4. Overall score, Pilodyn, branch angle, branching score and tree height showed the highest heritability.

  • Haapanen, ORCID ID:E-mail:
  • Annala, ORCID ID:E-mail:
  • Velling, 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 7194, category Article
T. Heikkilä. (1925). Kasvututkimuksia Perä-Pohjolasta. Acta Forestalia Fennica vol. 29 no. 4 article id 7194. https://doi.org/10.14214/aff.7194
English title: Growth studies in the northernmost Finland.

There is little knowledge about the value increment of the stands that are about to become mature for felling. Sample plots were measured in Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) stands in the most common forest site types in Rovaniemi, in northernmost Finland. Sample trees were chosen from dominant and codominant trees of the stand.

The value increments for the stands were generally very low. The average rotation of the studied stands would be 160 years. In the better forest site type, the increments of basal-area, volume and form height decrease slowly as the diameter of the tree increases. The value increment can give valuable information for intermediate fellings. They should be targeted mainly to large codominant trees and partly also in dominant trees that do not yet give logs, because their value increment is low.

The PDF includes a summary in German.

  • Heikkilä, ORCID ID:E-mail:
article id 7193, category Article
Aimo Kaarlo Cajander. (1926). The theory of forest types. Acta Forestalia Fennica vol. 29 no. 3 article id 7193. https://doi.org/10.14214/aff.7193

The forest sites have typically been classified by two principles, either as stand quality classes or as locality (site) classes. This article describes the principles of Finnish forest site types (forest quality classes) which are based on classification of localities according to their forest plant associations. All the stands that belong to the same forest site type are characterized by a distinct, more or less identical plant species composition. The forest site types are independent of the tree species. The forest site types in a larger area are relatively numerous, but can be grouped according to their normal form. The Finnish forests are separated to dry moss forest class, the moist moss-forest forest class and grass-herb forest class. The different forest site types belonging to the classes are described in detail. Growth of the trees is different for the different forest site types, but varies little within a same site type. The forest site types suit therefore well for the purposes of forest mensuration and for yield tables. The forest site types reflect also the properties of the soil.

  • Cajander, ORCID ID:E-mail:
article id 7192, category Article
Aimo Kaarlo Cajander. (1925). Metsätyyppiteoria. Acta Forestalia Fennica vol. 29 no. 2 article id 7192. https://doi.org/10.14214/aff.7192
English title: The theory of forest types.

The forest sites have typically been classified by two principles, either as stand quality classes or as locality (site) classes. This article describes the principles of Finnish forest site types (forest quality classes) which are based on classification of localities according to their forest plant associations. All the stands that belong to the same forest site type are characterized by a distinct, more or less identical plant species composition. The forest site types are independent of the tree species. The forest site types in a larger area are relatively numerous, but can be grouped according to their normal form. The Finnish forests are separated to dry moss forest class, the moist moss-forest forest class and grass-herb forest class. The different forest site types belonging to the classes are described in detail. Growth of the trees is different for the different forest site types, but varies little within a same site type. The forest site types suit therefore well for the purposes of forest mensuration and for yield tables. The forest site types reflect also the properties of the soil.

  • Cajander, ORCID ID:E-mail:
article id 5547, category Article
Tiina Tolvanen-Sikanen, Pertti Harstela, Lauri Sikanen. (1995). A game theoretic simulation model for quality oriented timber supply to sawmills. Silva Fennica vol. 29 no. 1 article id 5547. https://doi.org/10.14214/sf.a9198

The first aim of this study was to develop a simulation model describing the flow of different timber qualities to different firms. The second aim was to study preliminary the factors which affect timber distributions. In addition, we tested the hypothesis that in a small sawmill firm the traditional way of organizing timber procurement does not direct effectively good quality logs to the special production. The game theoretic approaching and the principles of Monte-Carlo simulation were applied in development of the simulation model. The most important factors of the model were tried to find for further studies with sensitive analysis. Empirical validation brought forth promising results in the area of one municipality. The buyer’s awareness of a marked stand, the seller’s willingness to sell a marked stand, the buyer’s ability to pay for wood and the proportion of first quality pine logs in a marked stand affected the distribution of pine logs. The results also supported the hypothesis that the traditional system, in which sawmills or their own forest departments procure themselves all timber needed, is not the most effective way to direct enough good quality timber to the special production.

  • Tolvanen-Sikanen, ORCID ID:E-mail:
  • Harstela, ORCID ID:E-mail:
  • Sikanen, ORCID ID:E-mail:
article id 5495, category Article
Hannu Salminen, Martti Varmola. (1993). Influence of initial spacing and planting design on the development of young Scots pine (Pinus sylvestris L.) stands. Silva Fennica vol. 27 no. 1 article id 5495. https://doi.org/10.14214/sf.a15656

Three Scots pine (Pinus sylvestris L.) plantations carrying 35 plots with initial spacings from 800 to 5,000 plants/ha were studied. Planting designs varied from a square to a rectangle with 5-metre row distance, the plant-to-plant distance being 0.8 metres. At current dominant height of 6 m, rectangularity had no effect on height, diameter, or volume growth of trees. Slight ovality of stems was observed in rectangular plots but the differences in the cross-wise mean diameters were very small, not over 1.1 mm in terms of plot-wise means. The diameter of the thickest living branch of a tree was linearly dependent of the dbh. The branches were clearly thicker between the planting rows at under 1,600 stems/ha stand density. A non-square planting pattern is a conceivable alternative when the line corridors suitable for mechanized silvicultural operations are preferred.
The PDF includes an abstract in Finnish.

  • Salminen, ORCID ID:E-mail:
  • Varmola, ORCID ID:E-mail:
article id 7092, category Article
August Renvall. (1923). Beobachtungen über die Exzentrizität des lappländischen Kiefernstammes. Acta Forestalia Fennica vol. 26 no. 4 article id 7092. https://doi.org/10.14214/aff.7092
English title: Observations on the eccentricity of pine trunks in Lapland.

The hard climate and other environmental conditions cause irregularities in the growth of trees in Lapland. Those changes weaken the characteristics of the tree for industrial use and hence lowers the timber price. The eccentricity is mainly caused by the strong wind burden.

The data for the article consists of 428 increment core samples from pine trees different ages, sizes and growth rate. There were collected in years 1910-1912 in Finnish Lapland, regions Utsjoki and Inari. The increment cores were collected on the height of 1.3 meters in south-north direction straight crosswise through the whole tree. The difference of length was measured between southern and northern half rays. Earlier studies show that the eccentricity remains the same in different heights of the tree. Hence studying the variations only on the breast height radiuses is possible.

The mean eccentricity is 12.3% and its maximum varies mostly between 20 and 25%. There are no differences in eccentricity between trees of different age classes or diameter. 

  • Renvall, ORCID ID:E-mail:
article id 5490, category Article
Timo Pukkala, Jari Karsikko, Taneli Kolström. (1992). A spatial model for the diameter of thickest branch of Scots pine. Silva Fennica vol. 26 no. 4 article id 5490. https://doi.org/10.14214/sf.a15651

The model predicts the base diameter of the thickest living branch of a tree growing in a planted or naturally regenerated even-aged stand. A mixed model type was used in which the residual variation was divided into within-stand and between-stand components. The study material consisted of 779 trees measured in 12 plots located in 20 to 35 years old Scots pine (Pinus sylvestris L.) stands (breast height age 10 to 20 years). Branch diameter was closely connected to the breast height diameter of the stem. In a stand of a certain age, competition by close neighbours slightly decreased branch diameter in a given diameter class. According to the model, the greatest difference is between trees subjected to very little competition and those subjected to normal competition. The model was used in simulated stands with varying age, density, and tree arrangement. The simulations showed that trees with rapid diameter growth at young age had thicker branches at a given breast height diameter than trees with slower diameter growth. However, a very slow growth rate did not produce trees with branches thinner than those possessing a medium growth rate.
The PDF includes an abstract in Finnish.

  • Pukkala, ORCID ID:E-mail:
  • Karsikko, ORCID ID:E-mail:
  • Kolström, ORCID ID:E-mail:
article id 5469, category Article
Risto Heikkilä, Kari Löyttyniemi. (1992). Growth response of young Scots pines to artificial shoot breaking simulating moose damage. Silva Fennica vol. 26 no. 1 article id 5469. https://doi.org/10.14214/sf.a15627

The main stem of young Scots pine (Pinus sylvestris L.) trees was cut off halfway along the current leading shoot and the two previous years’ leading shoots to simulate moose (Alces alces) damage. Trees of the same size were chosen as controls before treatments. The experiment was inspected ten years after artificial stem breakage. Removing the current leading shoot and the second shoot did not essentially affect the height and diameter growth of the trees. Removal down to the third shoot reduced the height as well as diameter growth. The average loss in growth was equivalent to less than one year’s growth. When the stem was cut off at the second or third shoot, stem crookedness and the presence of knots resulted in stem defects that will subsequently reduce the sawtimber quality. A high proportion of the stem defects will obviously still be visible at the first thinning cutting. Removing injured trees as pulpwood and pruning the remaining parts of cut stems evidently improves the quality of pine stand with moose damage.

The PDF includes an abstract in Finnish.

  • Heikkilä, ORCID ID:E-mail:
  • Löyttyniemi, ORCID ID:E-mail:
article id 7085, category Article
Yrjö Ilvessalo. (1923). Ein Beitrag zur Frage der Korrelation zwischen den Eigenschaften des Bodens und dem Zuwachs des Waldbestandes. Acta Forestalia Fennica vol. 25 no. 10 article id 7085. https://doi.org/10.14214/aff.7085
English title: Paper on the correlation between the characteristics of the soil and the growth of forest stand.

The study is based on the results of the soil studies by Valmari (1921) and the growth inventories of respective areas. The aim is to show the connection of soil fertility (nutrient content) and forest growth with means of correlation calculations. The examined nutrients were nitrogen, calcium and phosphorus, also the electrolyte content was studied.

The results show that with increase of nitrogen content of the soil the growth of pine stand increases as well. The correlation is clearly identified. The number of birch and spruce stands is too small for systematic review. For calcium there is a similar kind of relation. With phosphorus content or amount of electrolytes the correlation with doesn’t exist. Also the loss on ignition test was conducted. The relation found is somewhat weak.
  • Ilvessalo, ORCID ID:E-mail:
article id 5442, category Article
Erkki Annila, Kari Heliövaara. (1991). Chemical control of cone pests in a Norway spruce seed orchard. Silva Fennica vol. 25 no. 2 article id 5442. https://doi.org/10.14214/sf.a15596

The effect of three pesticides containing either dimethoate (0.5% a.i.), permitrin (0.5%) or triadimephon (0.5%) on the cone pests and flowering biology of Norway spruce (Picea abies (L.) H. Karst.) was tested in a seed orchard in mid-May or in the beginning of June. The pesticide treatments significantly reduced infestation by Laspeyresia strobiella and Kaltenbachiella strobi only. Variation in the number of cones infested by both insects and cone rusts was high between the spruce clones. Generally, the pesticides did not affect flower viability, seed quality or seed germination, but reduced drastically the germination capacity of pollen in vitro. In practice, sufficient control cannot be achieved with concentrations or methods used in the present study.

The PDF includes an abstract in Finnish.

  • Annila, ORCID ID:E-mail:
  • Heliövaara, ORCID ID:E-mail:
article id 5412, category Article
Jari Parviainen. (1990). Metsäpuiden paakkutaimituotannon nykynäkymät. Silva Fennica vol. 24 no. 1 article id 5412. https://doi.org/10.14214/sf.a15564
English title: Future trends for containerized tree seedling production: A literature review.

Containerized tree seedlings will be used on an increasing scale in the future in different parts of the world. There are number of techniques for the production of small one-year-old seedlings but it has not been possible to develop a completely satisfactory methods for large containerized seedlings production. In the long-term development of pine plantations established with containerized seedlings the greatest problem has been deformation of the root system. With a new method, based on a sheet of peat and root pruning, it has been possible to produce conifer seedlings with a good root regeneration potential and favourable morphological root system development. The use of small containerized seedlings allows an increase in planting density without any marked increase in regeneration costs.

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  • Parviainen, ORCID ID:E-mail:
article id 5388, category Article
Martti Varmola. (1989). Männyn istutustaimikoiden lustonleveysmalli. Silva Fennica vol. 23 no. 4 article id 5388. https://doi.org/10.14214/sf.a15546
English title: A model for ring width of planted Scots pine.

Ring width at breast height is presented as a function of stem radius at breast height, the ratio between the diameter of a tree and the basal area median diameter, site index, and density of stand. By means of a conversion model ring width at stump height can be estimated as a function of ring width at breast height.

According to previous studies substantially better wood quality can be expected if mean width near the pith at stump height decreases from 3 to 2 mm. According to the present study only on the poorest sites suitable for Scots pine (Pinus sylvestris L.) planting (poor Vaccinium type) the ring width is less than 3 mm at stump height even in the thickest trees. On more fertile sites a substantial increase in the recommended planting density is required, if the mean ring width is aimed to be less than 3 mm. On the best sites it is impossible to reach mean ring width of less than 2 mm, when the density is less than 4,000 stems/ha. Only the thinnest trees on the poorest sites can have a mean ring width less than 2mm.

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  • Varmola, ORCID ID:E-mail:
article id 5364, category Article
Urban Bergsten. (1988). Invigoration and IDS-sedimentation of Pinus sylvestris seeds from northern Finland. Silva Fennica vol. 22 no. 4 article id 5364. https://doi.org/10.14214/sf.a15521

In Northern Finland as well as in Northern Sweden there is a shortage of high-quality Scots pine (Pinus sylvestris L.) seeds, mostly due to unsuitable temperatures during the development and maturation of cones and seeds. Methods have been developed for elimination of non-productive seeds and for invigoration of seeds. In the present work, these methods were tested on poorly developed seed lot from Rovaniemi, Northern Finland (66°15’–66°30’; 180 m a.s.l.). The seeds were conditioned using the following treatments:

1. PREVAC method (5 min, 97 kPa below atmospheric pressures) for removal of mechanically damaged seeds (7%)

2. Invigoration using incubation at controlled moisture content (30% f.w) and continuous air supply, for 14 days at 5°C.

3. Additional water supply for 16 hours at 5°C.

4. Drying in dehumidified air until a near maximum difference in density between viable and dead seeds was obtained

5. Separation in a sedimentation flume to achieve a gradient of fractions of different germination rate and capacity.

The treatments resulted in an improvement of germination percentage from 33 to about 95% and a reduction in mean germination time from 8.8 days to 6 days if the control and the best fractions (32% seeds) were compared.

  • Bergsten, ORCID ID:E-mail:
article id 5266, category Article
Matti Kärkkäinen. (1986). Malli männyn, kuusen ja koivun puuaineen oksaisuudesta. Silva Fennica vol. 20 no. 2 article id 5266. https://doi.org/10.14214/sf.a15445
English title: Model of knottiness of wood material in pine, spruce and birch.

A computer model was developed for predicting knottiness of wood material of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.) and birch (Betula sp). The prediction included location of knots, their size and quality, i.e. if they are dead or living knots. The model suits best for tree species where branches are born at the base of shoots, in Finland such tree species is Scots pine.

The usefulness of the model was tested in the prediction of knots in wooden elements of joinery industry. According to the results, the shape of cross section affects the surface quality of elements. Especially useful is a quadratic cross section as it increases the probability to get a knotless surface.

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  • Kärkkäinen, ORCID ID:E-mail:
article id 5251, category Article
Markku Halinen. (1985). Männyn nuoruusvaiheen kasvunopeuden vaikutus sahatavaran laatuun. Silva Fennica vol. 19 no. 4 article id 5251. https://doi.org/10.14214/sf.a15430
English title: The effect of the growth rate of young Scots pine on the quality of sawn goods.

Totally 653 battens and planks sawn from butt logsof Scots pine (Pinus sylvestris L.) were chosen from 3 saw mills. The sawn goods were sorted according to normal sorting principles. In order to determine growth rate in the youth, the mean value of the average ring width was measured at the butt end at various distances from the pith.

The average ring width increased as the quality of the sawn goods decreased. The difference between the quality classes in ring width was measured between 2 and 4 cm from the pith. As the size of sawn goods, and, simultaneously, the log size increased, the average ring width increased in a given quality class. Research reinforced previous results, in which slow diameter growth of young Scots pines has been shown to reflect the good quality of sawn goods.

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  • Halinen, ORCID ID:E-mail:
article id 5246, category Article
Matti Kärkkäinen, Markku Halinen. (1985). Mäntysahatukkien minimivaatimusten täsmentäminen. Silva Fennica vol. 19 no. 3 article id 5246. https://doi.org/10.14214/sf.a15425
English title: Reappraisal of minimum requirements of Scots pine saw logs.

A test sawing was made of 807 Scots pine (Pinus sylvestris L.) saw logs of varying size and quality. The most important knot characteristic affecting the value of sawn goods was the diameter of the thickest dry knot. The new minimum requirements for pine logs were proposed on the basis of top diameter of the log and the diameter of the thickest dry and living knot.

The PDF includes a summary in English

  • Kärkkäinen, ORCID ID:E-mail:
  • Halinen, ORCID ID:E-mail:
article id 5246, category Article
Matti Kärkkäinen, Markku Halinen. (1985). Mäntysahatukkien minimivaatimusten täsmentäminen. Silva Fennica vol. 19 no. 3 article id 5246. https://doi.org/10.14214/sf.a15425
English title: Reappraisal of minimum requirements of Scots pine saw logs.

A test sawing was made of 807 Scots pine (Pinus sylvestris L.) saw logs of varying size and quality. The most important knot characteristic affecting the value of sawn goods was the diameter of the thickest dry knot. The new minimum requirements for pine logs were proposed on the basis of top diameter of the log and the diameter of the thickest dry and living knot.

The PDF includes a summary in English

  • Kärkkäinen, ORCID ID:E-mail:
  • Halinen, ORCID ID:E-mail:
article id 5172, category Article
Pekka Hynninen, Pentti Sepponen. (1983). Erään suoalueen ojituksen vaikutus purovesien laatuun Kiiminkijoen vesistöalueella, Pohjois-Suomessa. Silva Fennica vol. 17 no. 1 article id 5172. https://doi.org/10.14214/sf.a15087
English title: The effect of drainage on the quality of brook waters in the Kiiminkijoki River basin, Northern Finland.

The present study deals with the effect of forest drainage on some quality factors of brook waters. Under study were several brooks in the basin of the Kiiminkijoki River as well as its main tributary, the Nuorittajoki River. These are located in Northern Finland and belong to the international water program Project Aqua.

The following values were determined for the water samples: pH, electric conductivity, colour, concentration of suspended solids., NO2, NO3, and NH4 nitrogen concentrations, dissolved and total phosphorus, and Ca, Mg, K and Fe concentrations. Water quality in the brooks was monitored prior to and after ditching. A statistically significant change was noted in colour, in the concentration of suspended solids, in the NH4 concentration and in some brooks also in the pH value and in the total phosphorus, K, and Fe concentrations.

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  • Hynninen, ORCID ID:E-mail:
  • Sepponen, ORCID ID:E-mail:
article id 5124, category Article
Leo Heikurainen, Samuli Joensuu. (1981). Metsäojituksen hydrologiset seurausvaikutukset. Silva Fennica vol. 15 no. 3 article id 5124. https://doi.org/10.14214/sf.a15065
English title: The hydrological effects of forest drainage.

The present paper deals with the most important factors of peatland hydrology and the influence of forest drainage on the hydrology of peatland itself and its surroundings. It is compiled of six seminar papers written by students in the Department of Peatland Forestry in the University of Helsinki. Special attention is paid to the hydrological consequenses of the maintenance of drained areas. Also ways and measures to minimize the negative environmental effects of these treatments are discusses.

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  • Heikurainen, ORCID ID:E-mail:
  • Joensuu, ORCID ID:E-mail:
article id 5071, category Article
Martti Ryynänen. (1980). X-ray radiography of ageing Scots pine seeds. Silva Fennica vol. 14 no. 1 article id 5071. https://doi.org/10.14214/sf.a15012

Soft X-ray radiation (Grenz rays) has been used in the X-ray radiography of seeds. It is based on the principle that the different parts of the seed absorb X-rays to a slightly varying extent. Empty seeds and empty regions in the seeds appears as dark areas on the film. X-ray radiography without staining and X-ray contrast radiography were compared to study the stored seeds of Scots pine (Pinus sylvestris L.). The results were compared with the results of germination in a Jacobsen germinator according to ISTA norms.

Normal X-ray radiography gave too good estimates of germinative capacity of the seeds, and was shown to suit only when it is used to study fully ripe seeds which have recently been collected in an undamaged condition. The results of X-ray contrast radiography when barium chloride was used as the stain, however, followed closely the germination results.

The PDF includes a summary in Finnish.

  • Ryynänen, ORCID ID:E-mail:
article id 5018, category Article
Pertti Laakso, Olli Saikku. (1979). Havaintoja karsituista männyistä sorvatun viilun laadusta. Silva Fennica vol. 13 no. 1 article id 5018. https://doi.org/10.14214/sf.a14872
English title: Observations on the quality of veneer from pruned Scots pine stems.
Original keywords: mänty; pystykarsinta; vaneri; laatu; viilu

The material was obtained from Scots pine (Pinus sylvestris L.) stems which were pruned 27 years earlier up to the height of 5–6 m. Rotary cutting was made from 16 pruned stems and 3 unpruned ones. The length of bolts was 70 cm and the thickness of veneer 1.5 mm. The proportion of good quality veneer was 46% in pruned stems and 14% in the others. Veneer with exellent quality was obtained from pruned stems up to the height of tree meters, that is to say a little under the pruning line.
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  • Laakso, ORCID ID:E-mail:
  • Saikku, ORCID ID:E-mail:
article id 4966, category Article
Markku Mäkelä. (1977). Seulontatuloksia Algol-monikäyttöhakkurin hakkeesta. Silva Fennica vol. 11 no. 2 article id 4966. https://doi.org/10.14214/sf.a14817
English title: Screening results on the chips made by Algol-multipurpose chipper.
Original keywords: hake; hakkurit; hakkeen laatu

The first part of this paper consists of a study based on the available literature concerning the analysis of chip quality in the sulphate pulp process and the factors having an effect on chip quality. Using the empirical material, the suitability of the Williams chip classifier in evaluating the quality of chips made by the Algol chipper is first studied. The distribution of length and thickness of pulpwood-, long logs-, whole tree-, and logging residue chips in different conditions determined by screening is then presented.

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  • Mäkelä, ORCID ID:E-mail:
article id 4886, category Article
Matti Keltikangas, Kustaa Seppälä. (1973). Metsälannoituksen edullisuuden vaihtelu. Silva Fennica vol. 7 no. 3 article id 4886. https://doi.org/10.14214/sf.a14723
English title: Variations in the profitability of forest fertilization.

About one million hectares of forests are fertilized annually in Finland. The goal of the present study was to find out, by means of calculations, how the profitability of forest fertilization varies with variations in the stage of development of tree crops, the quality of the site and its geographical location. Calculations concerned bot fertilization of forests in mineral soil sites and in drained peatlands. The study is a part of a larger project concerning the order of profitability of different forest improvement measures in different conditions. The problems dealt with in this study were approached from the point of view of national economy.

On the basis of two empirical materials it is shown that there is a high correlation between the stand growth percentages before and after the fertilization. Applying the results to existing yield tables the authors calculate benefit/cost ratios showing the stage of development of the stand, the quality of the site and its geographical location. According to the results, fertilization is more profitable in sites of medium fertility than on poor sites. Profitability decreases rather fast from south to north and with decreasing timber prices. 

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  • Keltikangas, ORCID ID:E-mail:
  • Seppälä, ORCID ID:E-mail:
article id 7012, category Article
Yrjö Ilvessalo. (1916). Mäntymetsikköjen valtapuitten kasvusta mustikka- ja kanervatyyppien kankailla Salmin kruununpuistossa. Acta Forestalia Fennica vol. 6 no. 1 article id 7012. https://doi.org/10.14214/aff.7012
English title: The growth of the dominant trees in Scots pine forests of Myrtillus and Calluna typesailla Salmin kruununpuistossa.

Tree growth is one of the factors that have been used to determine the site quality. The aim of the study was to show that growth of single trees growing on a same forest site class are similar, but differ from trees growing on a different site type. To compare the tree growth, a stem analysis was performed to dominant trees in Scots pine (Pinus sylvestris L.) stands, measured in 15 Myrtillus type sample plots and in 15 Calluna type sample plots in state forests in Salmi, situated in north side of Lake Ladoga. The height growth when the tree was young was higher in the trees growing in the Myrtillus type than in the Calluna type. Also, the trees of same age are higher in Myrtillus type stand than in the Calluna type. In Calluna type, the height growth, however, evens out later in age than in the Myrtillus type. The volume growth of the trees begins to increase earlier in Myrtillus type, and is higher than in Calluna type. Similarly, the diameter growth in breast height is higher in the Myrtillus type.

The PDF includes a summary in German.

  • Ilvessalo, ORCID ID:E-mail:
article id 4768, category Article
Veijo Heiskanen. (1968). Havaintoja eräiden vikaisuuksien vaikutuksesta mäntytukkien sahauksessa. Silva Fennica vol. 2 no. 3 article id 4768. https://doi.org/10.14214/sf.a14553
English title: Influence of some log defects in sawing of pine logs.

The present paper presents studies on the influence of some relatively common defects of Scots pine logs in Northern Finland on both the sawing yield and on the quality of the sawn goods. The study was based on test sawing of 25 logs for each of the defects (upright limb, heart shake and various kinds of wounds and scars) at Karihaara sawmill. The yield was graded into grades used for export timber according to the system of the sawmill. The proportion of the different export grades (U/S), fifths, sixths and culls) were used as characteristics together with the ratio of raw-wood consumption expressed as cu.ft/std.

Upright limbs occurring in a piece of sawn timber was shown to lower its quality to fifth grade in 43.5%, to sixth grade in 46.8% and to the category of culls in 6.5% of all cases. Only 3.2% of the cases the piece remained in U/S-grades. The size of the upright limb was the most important factor lowering the quality and affecting the ratio of raw-wood consumption.

Heart shakes are relatively common defects in pine logs deriving from over-mature trees. The quality-decreasing influence on the sawing yield depends clearly on the length of the shake in the cross-section. The same characteristics also decreases the ratio of raw-wood consumption. In addition, twisting and star shakes are considerably more harmful than straight ones. If rot occurs in connection with shakes, the places marred by the shakes are only capable of yielding sixth-grade sawn goods or culls.

Scar encountered in logs affect the sawn yield and its quality to quite a varying degree, but these defects themselves may also vary considerably both in size and quality. The length of the scar is highly significant as a quality-decreasing factor. If, in addition, rot is encountered, the defect is of a severe nature.

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  • Heiskanen, ORCID ID:E-mail:
article id 4760, category Article
Veijo Heiskanen. (1968). Kuusitukkien laatuluokkajakautuma Etelä-Suomessa. Silva Fennica vol. 2 no. 1 article id 4760. https://doi.org/10.14214/sf.a14544
English title: Grade distribution of Norway spruce logs in Southern Finland.

The aim of the present study was to find the factors influencing the distribution of Norway spruce (Picea abies (L.) H. Karst.) logs on various grades with special stress on the effects of the grade on the value of logs. The material was obtained from ten sawmills located in Southern Finland by grading a total of 13,559 logs.

The results showed that knottiness in its different forms of appearance is the most important factor influencing the quality of spruce logs. Its significance is clearly greater in spruce than in Scots pine saw logs. Among the other defects, the most common are crooks. Even scars and decay occur to a considerable degree, but other defects seldom affect the grade. The quality of butt logs is markedly better than that of top logs. Both in butt and top logs the smallest logs in diameter are of poorer quality. However, in the largest diameter classes the quality begins again to decrease.

The difference in the quality of logs of the same grade at various sawmills is very small. The results of grading at varying times at the same sawmill show greater differences than can be observed between different sawmills. However, the logs of sawmills that procure the timber from coastal areas and islands are inferior to those which procure the timber from the mainland.

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  • Heiskanen, ORCID ID:E-mail:
article id 4744, category Article
Pekka Tiililä. (1967). Tutkimuksia eräiden ulkomaisten puulajien siemensadon laadusta Suomessa. Silva Fennica vol. 1 no. 2 article id 4744. https://doi.org/10.14214/sf.a14454
English title: Studies on the quality of seed yields in some foreign tree species in Finland.

The aim of this present study was to elucidate the quality of seed of foreign tree species grown in Finland, and the factors which have affected the quality of the seed yields. Due to the smallness of the material, however, no far-fetching conclusions can be drawn. The bulk of the seeds were collected in the fall of 1964. The samples of seeds were X-rayed and their classification to empty seeds and full seeds of four quality classes was done on the basis of the anatomical structures. The species studied (a total of 34 species) belonged to the following genera: Abies, Chamaecyparis, Larix, Picea, Pinus, Pseudotsuga, Thuja and Tsuga.

The percentage of empty seeds was throughout quite high. The reasons for the generation of empty seeds probably originate from the special nature of the stands from which the seeds were collected. As a rule, the stands were young and small in area, which may have caused weak pollination and self-pollination leading to embryo mortality. Also, insect damages were observed.

Seeds with albumen still discernible, although the embryo had died, occurred to some extent. In some Larix species, even the bulk of the seeds recorded as full belonged in this group.

The ripening of seeds with embryos was quite successful in spite of the fact that the temperature sum of the year of ripening was slightly below the average in Finland. For instance, all Abies species ripened almost completely.

According to the results, it can be expected that the tree species examined in this study are able to produce rich yields of good-quality seed in Finland, provided that the ovules are well pollinated and self-pollination does not take place to a large extent.

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  • Tiililä, ORCID ID:E-mail:
article id 7519, category Article
Jori Uusitalo. (1997). Pre-harvest measurement of pine stands for sawing production planning. Acta Forestalia Fennica no. 259 article id 7519. https://doi.org/10.14214/aff.7519

To enhance the utilization of the wood, the sawmills are forced to place more emphasis on planning to master the whole production chain from the forest to the end product. One significant obstacle to integrating the forest-sawmill-market production chain is the lack of appropriate information about forest stands. Since the wood procurement point of view in forest planning systems has been almost totally disregarded there has been a great need to develop an easy and efficient pre-harvest measurement method, allowing separate measurement of stands prior to harvesting. The main purpose of this study was to develop a measurement method for Scots pine (Pinus sylvestris L.) stands which forest managers could use in describing the properties of the standing trees for sawing production planning.

Study materials were collected from ten Scots pine stands located in North Häme and South Pohjanmaa, in Southern Finland. The data comprise test sawing data on 314 pine stems, diameter at breast height (dbh) and height measures of all trees and measures of the quality parameters of pine sawlog stems in all ten study stands as well as the locations of all trees in six stands. The study was divided into four sub-studies which deal with pine quality prediction, construction of diameter and dead branch height distributions, sampling designs and applying height and crown height models. The final proposal for the pre-harvest measurement method is a synthesis of the individual sub-studies.

Quality analysis resulted in choosing dbh, distance from stump height to the first dead branch, crown height and tree height as the most appropriate quality characteristics of Scots pine. Dbh and dead branch height are measured from each pine sample tree while height and crown height are derived from dbh measures by aid of mixed height and crown height models. Pine and spruce diameter distribution as well as dead branch height distribution are most effectively predicted by the kernel function. Roughly 25 sample trees seem to be appropriate in pure pine stands. In mixed stands the number of sample trees needs to be increased in proportion to the intensity of pines in order to attain the same level of accuracy.

  • Uusitalo, ORCID ID:E-mail:
article id 7508, category Article
Tapani Lahti. (1995). Understorey vegetation as an indicator of forest site potential in Southern Finland. Acta Forestalia Fennica no. 246 article id 7508. https://doi.org/10.14214/aff.7508

The relationship between site characteristics and understorey vegetation composition was analysed with quantitative methods, especially from the viewpoint of site quality estimation. Theoretical models were applied to an empirical data set collected from the upland forests of Southern Finland comprising 104 sites dominated by Scots pine (Pinus sylvestris. L.) and 165 sites dominated by Norway spruce (Picea abies (L.) H. Karst.). Site index H100 was used as an independent measure of site quality.

A new model for the estimation of site quality at sites with a known understorey vegetation composition was introduced. It is based on the application of Bayes’ theorem to the density function of site quality within the study area combined with the species-specific presence-absence response curves. The resulting probability density function may be used for calculating an estimate for the site variable

Using this method, a jackknife estimate of site index H100 was calculated separately for pine- and spruce-dominated sites. The results indicated that the cross-validation root mean squared error (RMSEcv) of the estimates improved from 2.98 m down to 2.34 m relative to the ”null” model (standard deviation of the sample distribution) in pine-dominated forests. In spruce-dominated forests RMSEcv decreased from 3.94 m down to 3.19 m.

In order to assess these results, four other estimation methods based on understorey vegetation composition were applied to the same data set. The results showed that none of the methods was clearly superior to the others. In pine-dominated forests RMSEcv varied between 2.34 and 2.47 m, and the corresponding range for spruce-dominated forest was from 3.13 to 3.57 m.

  • Lahti, ORCID ID:E-mail:
article id 7675, category Article
Erkki Tomppo. (1992). Satellite image aided forest site fertility estimation for forest income taxation. Acta Forestalia Fennica no. 229 article id 7675. https://doi.org/10.14214/aff.7675

Two operative forest site class estimation methods utilizing satellite images have been developed for forest income taxation purposes. For this, two pixelwise classification methods and two post-processing methods for estimating forest site fertility are compared using different input data. The pixelwise methods are discriminant analysis, based on generalized squared distances, and logistic regression analysis. The results of pixelwise classifications are improved either with mode filtering within forest stands or assuming a Markov random field type dependence between pixels. The stand delineation is obtained by using ordinary segmentation techniques. Optionally, known stand boundaries given by the interpreter can be applied. The spectral values of images are corrected using a digital elevation model of the terrain. Some textural features are preliminary tested in classification. All methods are justified by using independent test data.

A test of the practical methods was carried out and a cost-benefit analysis computed. The estimated cost saving in site quality classification varies from 14% to 35% depending on the distribution of the site classes of the area. This means a saving of about 2.0–4.5 million FMK per year in site fertility classification for income taxation purposes. The cost savings would rise even to 60% if that version of the method were chosen where field checking is totally omitted. The classification accuracy at the forest holding level would still be similar to that of traditional method.

The PDF includes a summary in Finnish.

  • Tomppo, ORCID ID:E-mail:
article id 7572, category Article
Tauno Kallio, Pekka Tamminen. (1974). Decay of spruce (Picea abies (L.) Karst.) in the Åland Islands. Acta Forestalia Fennica no. 138 article id 7572. https://doi.org/10.14214/aff.7572

In 1972, all Norway spruce (Picea abies (L.) H. Karst.) trees of a minimum 7 cm diameter at breast height growing in the sample plots of the Sixth National Forest Inventory were examined on the main island of Aland, Finland. The soundness of standing trees was estimated by means of external characteristics and increment borer chips. The trees were then felled and measured. They were cut into lengths, and the type and extent of decay were studied.

30% of the trees examined was affected by butt rot, ca. 3% by wound decay. A comparison of the results with those of the Sixth National Forest Inventory justifies the estimate that in Aland 23% of spruce trees exceeding 7 cm in diameter at 1.3 m had butt rot.

The proportion of decayed trees in the cubic volume was 31%. Decayed wood material accounted for 5% of the volume including bark. Butt rot increased towards the mature stands. The reduction in the number of timber trees due to decay was 14.5%, in their volume 21.5%, and in the volume of sulphite pulpwood 12%. The share of sulphate pulpwood increased from 1 to 10%. The total reduction in usable wood was 6.3%. The stumpage price of the trees fell by 10.3%. As the degree of decay increased the increment percentage of the trees decreased. The most common cause of butt rot was Fomes annosus (Heterobasidion annosum) found in 46% of the number of decayed trees. Armillaria mellea was found in 16%. Bacteria were found in 50% of the decayed trees.

The PDF includes a summary in Finnish.

  • Kallio, ORCID ID:E-mail:
  • Tamminen, ORCID ID:E-mail:
article id 4613, category Article
Veijo Heiskanen. (1951). Mäntysahatukkien laatuarvioinnin tarkkuudesta. Silva Fennica no. 69 article id 4613. https://doi.org/10.14214/sf.a14009
English title: Accuracy of quality grading of Scots pine saw logs.

Silva Fennica Issue 69 includes presentations held in 1948-1950 in the fourth professional development courses, arranged for foresters working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

This presentation discusses accuracy of the quality grading of Scots pine (Pinus sylvestris L.) saw logs suggested by professor Ilmari Vuoristo based on a data collected by Valtiala. According to the study, greatest inaccuracies in the grading by visual inspection was caused by differences between the evaluators.

  • Heiskanen, ORCID ID:E-mail:
article id 4613, category Article
Veijo Heiskanen. (1951). Mäntysahatukkien laatuarvioinnin tarkkuudesta. Silva Fennica no. 69 article id 4613. https://doi.org/10.14214/sf.a14009
English title: Accuracy of quality grading of Scots pine saw logs.

Silva Fennica Issue 69 includes presentations held in 1948-1950 in the fourth professional development courses, arranged for foresters working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

This presentation discusses accuracy of the quality grading of Scots pine (Pinus sylvestris L.) saw logs suggested by professor Ilmari Vuoristo based on a data collected by Valtiala. According to the study, greatest inaccuracies in the grading by visual inspection was caused by differences between the evaluators.

  • Heiskanen, ORCID ID:E-mail:
article id 4612, category Article
Veijo Heiskanen. (1951). Mäntysahatukkien laadun mukaisista arvosuhteista. Silva Fennica no. 69 article id 4612. https://doi.org/10.14214/sf.a14008
English title: Value grading of Scots pine saw logs.

Silva Fennica Issue 69 includes presentations held in 1948-1950 in the fourth professional development courses, arranged for foresters working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

Quality grading has been rarely used in pricing of saw logs due to lack of knowledge on how the quality of logs affects the value of the sawn wood. This presentation discusses the subject based on unpublished data professor Ilmari Vuoristo collected in 1930s on effects of timber grading on the quality and value of sawn wood. The quality classification developed by professor Vuoristo is presented.

  • Heiskanen, ORCID ID:E-mail:
article id 4611, category Article
Veijo Heiskanen. (1951). Sahatukkien laatuluokittelulla saavutettavista eduista. Silva Fennica no. 69 article id 4611. https://doi.org/10.14214/sf.a14007
English title: Benefits of qualitative classification of saw logs.

Silva Fennica Issue 69 includes presentations held in 1948-1950 in the fourth professional development courses, arranged for foresters working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

This presentation describes benefits of the qualitative classification of saw logs to forest owners and forest industry.

  • Heiskanen, ORCID ID:E-mail:
article id 4611, category Article
Veijo Heiskanen. (1951). Sahatukkien laatuluokittelulla saavutettavista eduista. Silva Fennica no. 69 article id 4611. https://doi.org/10.14214/sf.a14007
English title: Benefits of qualitative classification of saw logs.

Silva Fennica Issue 69 includes presentations held in 1948-1950 in the fourth professional development courses, arranged for foresters working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

This presentation describes benefits of the qualitative classification of saw logs to forest owners and forest industry.

  • Heiskanen, ORCID ID:E-mail:
article id 4610, category Article
Veijo Heiskanen. (1951). Sahatukkien laatuluokittelutavat. Silva Fennica no. 69 article id 4610. https://doi.org/10.14214/sf.a14006
English title: Methods of saw log classification according to quality.

Silva Fennica Issue 69 includes presentations held in 1948-1950 in the fourth professional development courses, arranged for foresters working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

This presentation describes the uses and principles of different kinds of grading of saw logs.

  • Heiskanen, ORCID ID:E-mail:
article id 4610, category Article
Veijo Heiskanen. (1951). Sahatukkien laatuluokittelutavat. Silva Fennica no. 69 article id 4610. https://doi.org/10.14214/sf.a14006
English title: Methods of saw log classification according to quality.

Silva Fennica Issue 69 includes presentations held in 1948-1950 in the fourth professional development courses, arranged for foresters working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

This presentation describes the uses and principles of different kinds of grading of saw logs.

  • Heiskanen, ORCID ID:E-mail:
article id 4609, category Article
F. E. Siimes. (1951). Sahatukkien laatuluokittelu sahatavarain käytön, lajittelun ja koesahausten valossa. Silva Fennica no. 69 article id 4609. https://doi.org/10.14214/sf.a14005
English title: Classification according to quality of saw logs in the light of use, grading and sawing tests of sawn timber.

Silva Fennica Issue 69 includes presentations held in 1948-1950 in the fourth professional development courses, arranged for foresters working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

This presentation describes the grading of sawn timber for export and domestic use, and suggests improvements to grading of the sawn products in the saw mills to better answer the needs of export.

  • Siimes, ORCID ID:E-mail:
article id 4608, category Article
V. Pöyhönen. (1951). Teollisuuden raakapuun yleiset laatuvaatimukset. Silva Fennica no. 69 article id 4608. https://doi.org/10.14214/sf.a14004
English title: General quality standards of industrial raw timber.

Silva Fennica Issue 69 includes presentations held in 1948-1950 in the fourth professional development courses, arranged for foresters working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

This presentation describes the development of standards for timber grades in Finland, and the present quality grades of raw timber for timber sales from state forests.

  • Pöyhönen, ORCID ID:E-mail:
article id 4608, category Article
V. Pöyhönen. (1951). Teollisuuden raakapuun yleiset laatuvaatimukset. Silva Fennica no. 69 article id 4608. https://doi.org/10.14214/sf.a14004
English title: General quality standards of industrial raw timber.

Silva Fennica Issue 69 includes presentations held in 1948-1950 in the fourth professional development courses, arranged for foresters working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

This presentation describes the development of standards for timber grades in Finland, and the present quality grades of raw timber for timber sales from state forests.

  • Pöyhönen, ORCID ID:E-mail:
article id 4516, category Article
M. Lappi-Seppälä. (1937). Karsimisesta arvopuun kasvatusta silmällä pitäen. Silva Fennica no. 42 article id 4516. https://doi.org/10.14214/sf.a14094
English title: Pruning as a means to produce quality timber.

 

 

  • Lappi-Seppälä, ORCID ID:E-mail:
article id 4500, category Article
Erkki Laitakari. (1937). Laatupuun kasvattamisesta. Silva Fennica no. 39 article id 4500. https://doi.org/10.14214/sf.a13910
English title: Production of good quality timber.

The issue 39 of Silva Fennica includes presentations held in professional development courses in 1935 that were arranged for foresters working in public administration. The presentations focus on practical issues in forest management and administration, especially in regional level.

This presentation describes methods of forest management that lead to production of qood quality timber, needed in the saw industry.

  • Laitakari, ORCID ID:E-mail:
article id 4498, category Article
Ilmari Vuoristo. (1937). Havupuumetsien laatuarvo ja laadun arviointi. Silva Fennica no. 39 article id 4498. https://doi.org/10.14214/sf.a13908
English title: Quality of coniferous forests and the value of timber.

The issue 39 of Silva Fennica includes presentations held in professional development courses in 1935 that were arranged for foresters working in public administration. The presentations focus on practical issues in forest management and administration, especially in regional level.

This presentation describes the quality of timber and coniferous forests in the point of view of saw industry.

  • Vuoristo, ORCID ID:E-mail:
article id 4446, category Article
Yrjö Ilvessalo. (1927). Methods for preparing yield tables. Silva Fennica no. 5 article id 4446. https://doi.org/10.14214/sf.a8394

The article is a review on methods used in Central Europe and in Finland to construct growth and yield tables, and on their defects and advantages. One of the main defects of growth and yield tables prepared previously in Central Europe is that the site quality classes for different tree species have been formed independently and using different principles. Thus, the yields of different tree species on a similar site can’t be compared. In addition, the quality classes of this kind of growth and yield tables and growth series are artificial.

The Society of Forestry in Finland (now Finnish Society of Forest Sciences) started to prepare new yield tables for the most important tree species in Finland in 1916. The new yield tables aimed to improve the yield tables made in Central Europe in two aspects. Firstly, the quality of the site of each sample plot was assessed on the spot and independently from the standing crop. Thus the sample plots of each site class in setting up the growth series can be treated as independent groups. Consequently, the quality classes are be the same for all tree species. Secondly, mathematical-statistical methods were used to determine which of the stands that belong to the same quality class belong also to the same growth series.

The PDF includes a summary in Finnish.

  • Ilvessalo, ORCID ID:E-mail:
article id 4441, category Article
Yrjö Ilvessalo. (1927). Preparation of growth and yield tables. Silva Fennica no. 4 article id 4441. https://doi.org/10.14214/sf.a8389

One of the difficulties in constructing growth and yield tables has been to determine which of the sample plots growing the same tree species and belonging to the same forest site type, with reference to the quality of stands, have to be included in the same growth series.

New growth and yield tables for the most important tree species were constructed in Finland in 1916–1919, using new principles that aim at avoiding some of the common weaknesses. There were two main differences to the earlier work. First, the site quality class (forest site type) was determined for each sample plot when the sample plot was measured, independently of the stand occupying the site. In this way it was possible to treat the sample plots of each site as an independent group from the beginning, and so that the quality classes were the same for all the tree species. Second, mathematic-statistical methods were used to deduct the so-called stem frequency distribution series, when studying which of the sample plots of the same quality class belong to the same growth series. They represent the average number of stems of the different diameter classes. A more detailed description of the method used to create the growth and yield tables is published in Acta Forestalia Fennica no. 15.

In the PDF is included a summary in Finnish.

  • Ilvessalo, ORCID ID:E-mail:

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