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Articles containing the keyword 'production'.

Category: Research article

article id 10132, category Research article
Yan Liu, Yuan Zhang, Qing Zhou, Jian Wu, Pingdong Zhang. (2019). Colchicine did not affect the viability of induced 2n pollen in Populus tomentosa. Silva Fennica vol. 53 no. 2 article id 10132. https://doi.org/10.14214/sf.10132
Highlights: The number of colchicine injections and the meiotic stage at which they were administered both had a significant effect on the occurrence rate of induced 2n pollen in Populus tomentosa; Treating male buds with 5000 ppm colchicine solution during meiosis led to a significant decrease in pollen production; Colchicine injection could induce P. tomentosa to produce 2n pollen and did not lead to dysfunction of induced diploid pollen.

Colchicine is widely used as a mutagen to induce production of diploid gametes in plants. However, whether colchicine affects induced pollen viability remains unclear. To clarify whether colchicine affected the viability of induced pollen, we induced production of diploid pollen by colchicine, followed by pollen germination in vitro and crossing induced pollen with normal gametes to produce triploid in Populus tomentosa Carrière. The results showed that the predominant meiotic stages and the number of colchicine injections had significant effects on the occurrence rates of induced 2n pollen. When the colchicine injection was given at diakinesis, a significant decrease in the pollen production per bud was observed (p < 0.001). The morphology of the colchicine-induced 2n pollen was similar to that of the natural 2n pollen in its ectexine structure. The pollen germination experiments revealed that there was also no significant difference in germination rates between the induced diploid pollen and natural 2n pollen grains, and 68 triploids were created by crossing colchicine-induced pollen. Our findings revealed that colchicine injection could induce P. tomentosa to produce 2n pollen and will not lead to dysfunction of induced diploid pollen.

  • Liu, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083, China; College of Bioscience and Biotechnology, Beijing Forestry University, Beijing 100083, China ORCID ID:E-mail: 342767649@qq.com
  • Zhang, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083, China; College of Bioscience and Biotechnology, Beijing Forestry University, Beijing 100083, China ORCID ID:E-mail: 409192881@qq.com
  • Zhou, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083, China; College of Bioscience and Biotechnology, Beijing Forestry University, Beijing 100083, China ORCID ID:E-mail: 876034493@qq.com
  • Wu, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083, China; College of Bioscience and Biotechnology, Beijing Forestry University, Beijing 100083, China ORCID ID:E-mail: 1269485709@qq.com
  • Zhang, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083, China; College of Bioscience and Biotechnology, Beijing Forestry University, Beijing 100083, China ORCID ID:E-mail: zhangpd@bjfu.edu.cn (email)
article id 7772, category Research article
Curt Almqvist. (2018). Improving floral initiation in potted Picea abies by supplemental light treatment. Silva Fennica vol. 52 no. 2 article id 7772. https://doi.org/10.14214/sf.7772
Highlights: Supplemental light treatment:
  • Increases the proportion of genotypes initiating reproductive buds.
  • Increases floral induction, especially of female floral buds.
  • Facilitates breeding programmes, and seed production of highly improved base material from new selections for vegetative production programmes, to be more efficient.

Light is an important environmental factor for all green plants. Its intensity, spectral composition and photoperiod can affect the regulatory pathways in plants that lead to floral initiation. In this report, results are presented from three experiments in which supplemental light with metal halide lamps (250 µmol m–2 s–1, 20 hours day–1, approx. 6 weeks) was tested as a complement to other flowering stimulation treatments (elevated temperature, treatment with gibberellin A4 and A 7 (GA4/7), restricted water supply) applied to potted Picea abies (L.) Karst. in the greenhouse. Flower stimulation in a greenhouse resulted in more floral initiation compared to flower stimulation outdoors. Supplemental light treatment increased floral initiation further, and to a larger extent in female than in male flowers. It also increased the proportion of trees and genotypes that induced reproductive buds. In a practical application of the supplemental light treatment to potted Picea abies breeding material, 90.6% of the clones produced either female or male flowers, or both. A subset of the same material kept outdoors, and thus subjected to natural light and temperatures, produced no flowers despite being treated with GA4/7 and receiving a restricted water supply. In conclusion, supplemental light treatment facilitates breeding programmes, and seed production of highly improved base material from new selections for vegetative production programmes, to be more efficient.

  • Almqvist, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83 Uppsala, Sweden ORCID ID: http://orcid.org/0000-0001-5739-4854 E-mail: curt.almqvist@skogforsk.se (email)
article id 1734, category Research article
Jyrki Hytönen, Paula Jylhä, Keith Little. (2017). Positive effects of wood ash fertilization and weed control on the growth of Scots pine on former peat-based agricultural land – a 21-year study. Silva Fennica vol. 51 no. 3 article id 1734. https://doi.org/10.14214/sf.1734
Highlights: Weed control decreased and fertilization increased vegetation height and shading of seedlings; Weed control decreased mortality, but fertilization had no effect; Despite improved foliar K concentration though ash fertilization, all trees in the trial had severe K deficiency after 21 years; Weed control increased growth by 20 m3 ha–1 and fertilization by 35 m3 ha–1 in 21 years.

The impacts of weed control, ash fertilization and their interaction were tested for the afforestation of former agricultural peat-based soil with Scots pine (Pinus sylvestris L.) in northern Finland in a factorial arrangement of four treatments. Weed control with herbicides was carried out in July 1 and 2 years from planting, and wood ash (5 Mg ha–1) was applied in the spring of the 2nd year. Various vegetation, tree growth and nutrient assessments were made over the 21-year study period. Weed control decreased the weed cover by 36–56 percentage points, vegetation height by 4–26 cm and thus shading of seedlings by vegetation for at least 4 years after planting. For the same period, ash fertilization increased vegetation height by 6–15 cm and shading of seedlings. Weed control reduced seedling mortality by 27 percentage points in 21 years, but ash fertilization had no significant effect. Ash fertilization increased foliar potassium and boron concentrations, but its effect declined, and severe K-deficiency was recorded 21 years after planting. Up to the 9th year, weed control had a greater influence on growth than fertilization. Later the significance of fertilization increased due to an aggravated K-deficiency. Stand volume at year 21 for the untreated control plots was 8 m3 ha–1. Weed control and fertilization increased stand volume by 20 and 35 m3 ha–1, with a combined effect of 55 m3 ha–1. The effects of weed control and fertilization were additive and no significant interactions were found. Due to severe K-deficiencies, re-fertilization of all treatments would be necessary for the continued survival and growth of Scots pine.

  • Hytönen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Teknologiakatu 7, FI-67100 Kokkola, Finland ORCID ID: http://orcid.org/0000-0001-8475-3568 E-mail: jyrki.hytonen@luke.fi (email)
  • Jylhä, Natural Resources Institute Finland (Luke), Green technology, Teknologiakatu 7, FI-67100 Kokkola, Finland ORCID ID:E-mail: paula.jylha@luke.fi
  • Little, Nelson Mandela Metropolitan University, George Campus, Western Cape, South Africa ORCID ID:E-mail: keith.little@nmmu.ac.za
article id 1563, category Research article
Kristina Ahnlund Ulvcrona, Dan Bergström, Urban Bergsten. (2017). Stand structure after thinning in 1–2 m wide corridors in young dense stands. Silva Fennica vol. 51 no. 3 article id 1563. https://doi.org/10.14214/sf.1563
Highlights: Boom corridor thinning (BCT) results in more stand structure heterogeneity than conventional thinning or pre-commercial thinning (PCT), maintaining both smaller-diameter trees and deciduous species; Neither dominant height nor number of possible future crop trees is jeopardized, and boom corridor thinning results in higher values of stem volume and biomass; The technique is flexible as various corridor types give similar stand structure results.

Boom corridor thinning (BCT) has been proposed as a cost-effective technique for biomass thinning (BT) in young dense stands. The objective of this study was to determine how various BCT operations affect stand structure following biomass thinning and to compare the results with conventional selective thinning methods. Two series of field experiments were established; BCT 1-series: Three sites in south of Sweden (9 and 11 m in mean and dominating tree height) with five treatments, including a control, conventional selective thinning and three BCT treatments (1 m and 2 m wide corridors and selective BCT). The second BCT series: Three regions in Sweden (in the north, centre and in the south), with two stand sites in each region with different tree heights (4/9 m and 5/10 m in mean/dominating tree height). Treatments were control, pre-commercial thinning (PCT), conventional selective thinning and BCT (high and low thinning). Following the first biomass thinning, BCT regimes and selective thinning methods resulted in similar stand structures based on the number of possible future crop trees (>80 mm in diameter at breast height). However, BCT maintained a higher diversity of tree sizes as well as more stems per hectare, including deciduous species, than the selective thinning approaches. The stands after BCT should have more vertical complexity, especially when compared to pre-commercial thinning. The structural heterogeneity resulting from BCT may also increase stand biodiversity and ecosystem service values.

  • Ahnlund Ulvcrona, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: kristina.ulvcrona@slu.se (email)
  • Bergström, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: dan.bergstrom@slu.se
  • Bergsten, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: urban.bergsten@slu.se
article id 1680, category Research article
Liisa Kulmala, Indre Žliobaitė, Eero Nikinmaa, Pekka Nöjd, Pasi Kolari, Kourosh Kabiri Koupaei, Jaakko Hollmén, Harri Mäkinen. (2016). Environmental control of growth variation in a boreal Scots pine stand – a data-driven approach. Silva Fennica vol. 50 no. 5 article id 1680. https://doi.org/10.14214/sf.1680
Highlights: High water potential and carbon gain during bud forming favoured height growth; High water potential during the elongation period favoured height growth; A spring with high carbon gain favoured diameter growth; The obtained regression models had generally low generalization performance.

Despite the numerous studies on year-to-year variation of tree growth, the physiological mechanisms controlling annual variation in growth are still not understood in detail. We studied the applicability of data-driven approach i.e. different regression models in analysing high-dimensional data set including continuous and comprehensive measurements over meteorology, ecosystem-scale water and carbon fluxes and the annual variation in the growth of app. 50-year-old Scots pine stand in southern Finland. Even though our dataset covered only 16 years, it is the most extensive collection of interactions between a Scots pine ecosystem and atmosphere. The analysis revealed that height growth was favoured by high water potential of the tree and carbon gain during the bud forming period and high water potential during the elongation period. Diameter growth seemed to be favoured by a winter with high precipitation and deep snow cover and a spring with high carbon gain. The obtained models had low generalization performance and they would require more evaluation and iterative validation to achieve credibility perhaps as a mixture of data-driven and first principle modeling approaches.

  • Kulmala, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: liisa.kulmala@helsinki.fi (email)
  • Žliobaitė, Aalto University, Department of Computer Science and Helsinki Institute for Information Technology, P.O. Box 11000, FI-00076 Aalto, Finland; University of Helsinki, Department of Geosciences and Geography, P.O. Box 64, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: zliobaite@gmail.com
  • Nikinmaa, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: eero.nikinmaa@helsinki.fi
  • Nöjd, Natural Resources Institute Finland (Luke), Bio-based business and industry, Tietotie 2, FI-02150 Espoo, Finland ORCID ID:E-mail: pekka.nojd@luke.fi
  • Kolari, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland; University of Helsinki, Department of Physics, P.O. Box 64, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: pasi.kolari@helsinki.fi
  • Kabiri Koupaei, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: kourosh.kabiri@helsinki.fi
  • Hollmén, Aalto University, Department of Computer Science and Helsinki Institute for Information Technology, P.O. Box 11000, FI-00076 Aalto, Finland; University of Helsinki, Department of Geosciences and Geography, P.O. Box 64, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: jaakko.hollmen@aalto.fi
  • Mäkinen, Natural Resources Institute Finland (Luke), Bio-based business and industry, Tietotie 2, FI-02150 Espoo, Finland ORCID ID:E-mail: harri.makinen@luke.fi
article id 1611, category Research article
Ilpo Ervasti. (2016). Wood fiber contents of different materials in the paper industry material chain expressed in roundwood equivalents (RWEs). Silva Fennica vol. 50 no. 4 article id 1611. https://doi.org/10.14214/sf.1611
Highlights: The paper industry material recycling chain consists of different material streams; Consumed paper products form a huge fiber source for industry. However, a reliable measuring system should be developed to quantify these fiber volumes; Converting factors are introduced to quantify the wood fiber contents of different paper industry-related materials of the chain, namely, wood pulp, paper and recovered paper; By using these conversion factors it is possible to convert for example global recovered paper utilization volumes into wood fiber volumes expressed in roundwood equivalents (RWEs).

At present, there are no means for reliably comparing the wood fiber contents of different material streams within the paper industry material chain with each other. The aim of this article is to introduce conversion factors that make it possible to quantify the volume of wood expressed in roundwood equivalent (RWE) values for different paper industry-related materials in the material chain. These conversion factors apply to wood pulp, paper, and recovered paper. European data are used in quantifying the paper industry material streams and calculating the RWE conversion factors. The introduced conversion factors can be used to estimate RWE volumes at a global scale. With assumption that paper recycling did not occur and that paper production volume remained unchanged, an additional volume of 666 million m3 RWEs would be required globally per annum to produce 167 million tons of virgin wood pulp to replace 222 million tons of recovered paper utilized by the paper industry in 2010. This volume is approximately the same as 1.6 times the total removal of wood in Europe (EU27), or the total annual removal of wood in the USA, Canada, and Brazil combined.

  • Ervasti, Aalto University, Industrial Engineering and Management, Maarintie 8, 02150 Espoo, Finland ORCID ID:E-mail: ilervasti@gmail.com (email)
article id 1564, category Research article
Stanislav Vacek, Zdeněk Vacek, Lukáš Bílek, Jaroslav Simon, Jiří Remeš, Iva Hůnová, Jan Král, Tereza Putalová, Miroslav Mikeska. (2016). Structure, regeneration and growth of Scots pine (Pinus sylvestris L.) stands with respect to changing climate and environmental pollution. Silva Fennica vol. 50 no. 4 article id 1564. https://doi.org/10.14214/sf.1564
Highlights: Pine forest stands showed positive development of stand structural characteristics related to their diversity, number of regeneration individuals and growth characteristics; Tree-ring width was positively correlated with precipitation, while it was negatively correlated with temperature in growing seasons; Mean NOx concentrations showed positive effect on radial growth of pine; Serious defoliation was caused by SO2 concentrations and N deposition in combination with extreme climate events.

Changes in the structure and development of managed Scots pine (Pinus sylvestris L.) stands with respect to changing environmental conditions were set for the period 1979–2015. The study was conducted in conditions of natural pinewoods and pine-oak sites on five permanent research plots (0.25 ha) in Eastern Bohemia, Czech Republic (CR). Studied forest stands showed positive development of stand structural characteristics related to their diversity, number of regeneration individuals and growth characteristics. The standing volume of regularly distributed tree layer in 2015 was in the range of 320–434 m3 ha–1, which indicates an increase by 5.9–20.0% over 10 years. Correlation between pine radial increment and the amount of precipitation was generally the strongest one. Positive statistically significant correlation between diameter increment and temperature was demonstrated only for the average March temperature of the current year. Within the CR, study site can be characterised as a medium polluted area both for sulphur and nitrogen, despite this SO2 concentrations and N deposition in combination with extreme climate events caused severe defoliation in pine stands. Conversely, radial growth was positively significantly correlated with mean NOx concentrations. Drought mainly in combination with even medium environmental pollution can further worsen the health status of pine stands in lowland areas of Central Europe. Thus, formulation of silvicultural techniques able to mitigate the impact of these stress factors is needed.

  • Vacek, Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129, 165 21 Prague, Czech Republic ORCID ID:E-mail: vacekstanislav@fld.czu.cz
  • Vacek, Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129, 165 21 Prague, Czech Republic ORCID ID:E-mail: vacekz@fld.czu.cz
  • Bílek, Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129, 165 21 Prague, Czech Republic ORCID ID:E-mail: bilek@fld.czu.cz
  • Simon, Mendel University in Brno, Faculty of Forestry and Wood Technology, Zemědělská 3, 613 00 Brno, Czech Republic ORCID ID:E-mail: jaroslav.simon@mendelu.cz
  • Remeš, Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129, 165 21 Prague, Czech Republic ORCID ID:E-mail: remesj@email.cz (email)
  • Hůnová, Czech Hydrometeorological Institute, Na Šabatce 17 143 06 Prague, Czech Republic ORCID ID:E-mail: hunova@chmi.cz
  • Král, Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129, 165 21 Prague, Czech Republic ORCID ID:E-mail: kraljan@fld.czu.cz
  • Putalová, Czech University of Life Sciences Prague, Faculty of Forestry and Wood Sciences, Kamýcká 129, 165 21 Prague, Czech Republic ORCID ID:E-mail: putalova@fld.czu.cz
  • Mikeska, University of Hradec Králové, Faculty of Science, Rokitanského 62, 500 03 Hradec Králové, Czech Republic ORCID ID:E-mail: Mikeska.Miroslav@uhul.cz
article id 1243, category Research article
Curt Almqvist, Gunnar Jansson. (2015). Effects of pruning and stand density on cone and pollen production in an experimental Pinus sylvestris seed orchard. Silva Fennica vol. 49 no. 4 article id 1243. https://doi.org/10.14214/sf.1243
Highlights: Pollen production of Pinus sylvestris began at the same age for all studied stand density and pruning height combinations but increased more rapidly at higher densities; Treatments with dense spacing increased seed production earlier; Many combinations of stand density and target height gave comparable levels of seed production, yielding a wide range of viable management options.

Seed orchards are the link between tree breeding and reforestation. This paper presents data on cone, seed and pollen production and seed quality gathered over 21 years in a Pinus sylvestris (L.) experimental seed orchard containing plots with 14 different combinations of stand density and targeted pruning height. The treatments’ stand densities ranged from 267 to 4000 stems ha-1, and the target graft heights ranged from 2 to 6 meters. Pollen production began at the same orchard age for all studied combinations of stand density and target height but the level of pollen production per hectare increased more rapidly in treatments with higher stand densities. In treatments with dense spacing, cone and seed production initially increased more rapidly than in treatments with wider spacing, thereby providing an earlier return on investment and a shorter seed production lag time. However, the levels of cone and seed production in such treatments over the entire study period were not appreciably different to those achieved in treatments with wider spacing and higher target height. The treatments did not differ substantially with respect to seed quality. These results show that comparable levels of seed production can be obtained with different combinations of stand density and target height, giving seed orchard owners and managers a wide range of viable management options.

  • Almqvist, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: curt.almqvist@skogforsk.se (email)
  • Jansson, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: gunnar.jansson@skogforsk.se
article id 1260, category Research article
Jyrki Hytönen, Anna Saarsalmi. (2015). Biomass production of coppiced grey alder and the effect of fertilization. Silva Fennica vol. 49 no. 1 article id 1260. https://doi.org/10.14214/sf.1260
Highlights: Fertilisation (wood ash, N, PK) did not affect grey alder biomass production; Leafless above-ground biomass of 17–20 year old stands was 52–57 Mg ha–1; MAI increased with increase of rotation length to the end of the follow-up period of 17–20 years; Coppicing increased stand density manifold.
We studied biomass production of two naturally originated grey alder (Alnus incana (L.) Moench) stands having a mixture of birch and willow located in central Finland. One of the stands was growing on a peatland site (Muhos) and the other on a mineral soil site (Juuka). The stands were clear-cut and fertilization experiments were laid out with several treatments. At Muhos, the treatments included nitrogen fertilisation with different amounts of wood ash and an unfertilized control. At Juuka, the treatments included nitrogen fertilisation either with ash or with PK, and ash and PK treatments alone and an unfertilized control. The sprouts at Muhos were grown for 17 years and at Juuka for 20 years. At Juuka the stand was clear-cut second time at the age of 20 years and grown for 8 years. The stands were measured several times and foliar samples were taken twice during the study period. Clear-cutting increased stem number manifold. The stand density of new coppiced forests after the clear-cutting decreased from 67 000–89 000 stems ha–1 at the age of 3–6 years to 10 000–12 000 stems ha–1 at the age of 17–20 years. On neither site fertilization affected biomass production of alders during the study period. Leafless above-ground biomass was 52–57 Mg ha–1 after 17–20 years. Mean annual leafless above-ground biomass production (MAI) increased with increase of rotation time. At the age of 17–20 years the MAI was 2.8–3.0 Mg ha a–1. At Muhos, ash increased foliar P and Ca concentrations, but decreased those of Mn.
  • Hytönen, Natural Resources Institute Finland, Silmäjärventie 2, FI-69100 Kannus, Finland ORCID ID:E-mail: jyrki.hytonen@luke.fi (email)
  • Saarsalmi, Natural Resources Institute Finland, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: anna.saarsalmi@luke.fi
article id 1135, category Research article
Matts Lindbladh, Per-Ola Hedwall, Ida Wallin, Annika M. Felton, Henrik Böhlenius, Adam Felton. (2014). Short-rotation bioenergy stands as an alternative to spruce plantations: implications for bird biodiversity. Silva Fennica vol. 48 no. 5 article id 1135. https://doi.org/10.14214/sf.1135
Highlights: There is a gap in knowledge regarding the biodiversity implications of replacing production forests with bioenergy stands; We compared the avian biodiversity of early rotation hybrid aspen stands and spruce plantations, the latter being the dominant production forest type in southern Sweden; Our results indicate that young hybrid aspen stands can support relatively diverse and distinctive bird communities.
Global efforts to decrease dependence on fossil fuels have increased interest in bioenergy production. One source of bioenergy is fast growing deciduous tree species, such as hybrid aspen (Populus × wettsteinii Hämet-Ahti). The majority of research on hybrid aspen which assesses biodiversity implications, has however primarily focused on agricultural lands as the reference condition. This has resulted in a substantial gap in our knowledge regarding the biodiversity implications of replacing production forest types with hybrid aspen, a form of reforestation taking place in northern Europe. In this study we address this knowledge gap by comparing the avian biodiversity of young hybrid aspen and spruce (Picea abies L.) plantations of similar age, the latter being the most prevalent forestry alternative in in southern Sweden. We found that hybrid aspen stands had higher bird species richness and abundance as well as a distinct community composition compared to the spruce stands. We suggest that the most likely driver was the greater structural and tree species complexity in the aspen stands, provided for by the fenced exclusion of ungulates from the regenerating hybrid aspen stands. Our results indicate that at least during early stages of regeneration, and in comparison to the dominating production forest type in the region, hybrid aspen stands can support relatively high levels of bird diversity, and a bird species composition more closely associated with broadleaf habitat types requiring restoration in this region.
  • Lindbladh, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: matts.lindbladh@slu.se (email)
  • Hedwall, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: per-ola.hedwall@slu.se
  • Wallin, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: ida.wallin@slu.se
  • Felton, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: annika.felton@slu.se
  • Böhlenius, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: henrik.bohlenius@slu.se
  • Felton, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: adam.felton@slu.se
article id 48, category Research article
Jyrki Hytönen, Lasse Aro. (2012). Biomass and nutrition of naturally regenerated and coppiced birch on cutaway peatland during 37 years. Silva Fennica vol. 46 no. 3 article id 48. https://doi.org/10.14214/sf.48
Biomass production and nutrient use of birch thickets with a mixture of willow on a cut away peatland in southern Finland over a period of 37 years was studied. Dense, naturally regenerated 16-year-old birch stands were cut down, fertilized with either wood ash (P 108 and K 339 kg ha–1) or PK fertilizer (P 50 and K 95 kg ha–1) or left unfertilized. The biomass production of the coppiced stands and one uncut stand was monitored for a period of 21 years. Soil nutrient and foliar nutrient concentrations were analyzed several times during the study period. Ash fertilization supplied more nutrients than PK fertilization and increased the soil nutrient amounts more. The foliar phosphorus concentration of birch on control plots indicated a severe phosphorus deficiency which was removed by PK and ash fertilization. Fertilization did not increase nutrient concentrations of the stem (wood + bark) nor the amount of nutrients bound in the biomass. Two energy wood rotations (16+21 years) produced 124–158 Mg ha–1 of leafless, above-ground biomass altogether corresponding to 61–78 Mg ha–1 of carbon. The highest biomass yield was achieved with a rotation of 37 years in the uncut stand (211 Mg ha–1). Corresponding values for mean annual increment (MAI) were 3.4–4.3 Mg ha–1 and 5.7 Mg ha–1. This study shows that the length of the rotation for birch in energy wood production should be longer than 21 years. PK and ash fertilization increased the biomass of coppiced 21-year-old birch by 23 Mg ha–1 and 33 Mg ha–1, respectively.
  • Hytönen, Finnish Forest Research Institute, Kannus, Finland ORCID ID:E-mail: jyrki.hytonen@metla.fi (email)
  • Aro, Finnish Forest Research Institute, Kannus, Finland ORCID ID:E-mail: lasse.aro@metla.fi
article id 450, category Research article
Miaoer Lu, Pekka Nygren, Jari Perttunen, Stephen G. Pallardy, David R. Larsen. (2011). Application of the functional-structural tree model LIGNUM to growth simulation of short-rotation eastern cottonwood. Silva Fennica vol. 45 no. 3 article id 450. https://doi.org/10.14214/sf.450
The functional-structural tree growth model LIGNUM was developed as a general research tool that can be applied to several tree species. The growth simulation of short-rotation eastern cottonwood (Populus deltoides Bartr. ex Marsh.) inherits the basic LIGNUM modeling concepts including modular tree structure, L-system-based description of structural development, and carbon budget. New developments of LIGNUM model in this study were the incorporation of a biochemically-derived photosynthesis submodel; nested time steps for simulating physiological processes, structural development, and annual biomass production; incorporation of field-measured weather data for modeling the response of physiological processes to environmental variation; and application of a Monte-Carlo voxel space submodel for simulating the stochasticity of tree growth and improving computational efficiency. A specific parameter system was applied for modeling P. deltoides growth in the central Missouri, USA, environment. This adaptation of LIGNUM was applied on modeling growth of P. deltoides in a short-rotation agroforestry practice. The simulated height and biomass growth were close to field observations. Visualization of simulation results closely resembled the trees growing in an open site. The simulated response of tree growth to variations in photon flux input was reasonable. The LIGNUM model may be used as a complement to field studies on P. deltoides in short-rotation forestry and agroforestry.
  • Lu, Deparment of Forestry, University of Missouri, Columbia, MO, USA ORCID ID:E-mail:
  • Nygren, The Finnish Society of Forest Science, P.O. 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: pekka.nygren@metla.fi (email)
  • Perttunen, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • Pallardy, Deparment of Forestry, University of Missouri, Columbia, MO, USA ORCID ID:E-mail:
  • Larsen, Deparment of Forestry, University of Missouri, Columbia, MO, USA ORCID ID:E-mail:
article id 145, category Research article
Jianbang Gan, C. T. Smith. (2010). Coupling greenhouse gas credits with biofuel production cost in determining conversion plant size. Silva Fennica vol. 44 no. 3 article id 145. https://doi.org/10.14214/sf.145
Biofuel plant size is one of the key variables in biofuel supply chain analysis as it plays a pivotal role in controlling the efficacy of both feedstock supply and feedstock-to-biofuel conversion. The unit production cost and greenhouse gas (GHG) balance of biofuels vary with plant size. We develop an analytical framework for integrating biofuel production costs and GHG balance derived from life-cycle analysis into supply chain optimization, followed by its application to ethanol production using forest biomass in the southern United States. We derive formulas for determining the optimal biofuel plant size and the corresponding feedstock supply radius based on the minimization of biofuel production costs less GHG benefits. Our results indicate that though biofuel plant size and feedstock supply radius should be augmented by considering GHG benefits, the GHG price will have a more significant impact on net biofuel production costs than on conversion plant size or feedstock supply radius. With a rise in the GHG price the net biofuel production cost tends to increase while the directions of change in plant size and feedstock supply radius are uncertain, depending upon the costs and GHG emissions of biomass transport and feedstock-to-fuel conversion. Combining GHG offset values with biofuel production costs enables us to more holistically examine the biofuel supply chain.
  • Gan, Department of Ecosystem Science and Management, Texas A&M University, Texas, USA ORCID ID:E-mail: j-gan@tamu.edu (email)
  • Smith, Faculty of Forestry, University of Toronto, Ontario, Canada ORCID ID:E-mail:
article id 163, category Research article
Blas Mola-Yudego. (2010). Regional potential yields of short rotation willow plantations on agricultural land in Northern Europe. Silva Fennica vol. 44 no. 1 article id 163. https://doi.org/10.14214/sf.163
The development of short rotation forestry for bioenergy requires accurate and reliable yield estimates. This paper analyses the current, expected and potential regional productivity of short rotation willow plantations for six countries in Northern Europe. The estimations for present productivity are based on empirical models, using data regarding management, and local productivity based on the regional cereal yields. The estimates of expected yield rely on the current trends of yield increase from commercial willow plantations in the region. The estimates for potential yield are based on climatic restrictions. The results show potential average yields of 9.5, 6.8, 7.9, 9.0, 9.3, and 8.0 odt ha–1 yr–1 for Denmark, Finland, Estonia, Latvia, Lithuania and Sweden, respectively. The results of the study also show that there is a wide regional variation between the different countries. In Denmark, Finland and Sweden there is a convergence between the future forecasts and the climatic potential yields in the areas of high productivity. The Baltic countries seem to present lower estimates of present productivity, reflecting possible socio-economic restrictions, although they show a high biomass potential. The methods presented in this study can be further developed in other areas where willow cultivation is considered, and can serve as a basis for future economic considerations.
  • Mola-Yudego, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: blas.mola@uef.fi (email)
article id 286, category Research article
Riitta Hänninen, A. Maarit I. Kallio. (2007). Economic impacts on the forest sector of increasing forest biodiversity conservation in Finland. Silva Fennica vol. 41 no. 3 article id 286. https://doi.org/10.14214/sf.286
In the next coming years, political decisions will be made upon future actions to safeguard forest biodiversity in Southern Finland. We address the economic consequences on the Finnish forest sector of conserving additional 0.5% to 5% of the old growth forest land in Southern Finland. The impacts on supply, demand and prices of wood and forest industry production are analysed employing a partial equilibrium model of the Finnish forest sector. An increase in conservation raises wood prices and thus the production costs of the forest industry. This makes sawnwood production fall, but does not affect paper and paperboard production. The forest owners’ aggregated wood sales income is unaffected or slightly increased, because an increase in stumpage prices offsets the decrease in the harvests. If conservation increases wood imports, negative effects on forest industry become smaller whereas aggregated forest owners’ income may decline depending on the magnitude of import substitution.
  • Hänninen, Finnish Forest Research Institute, Unioninkatu 40 A, FI-00170 Helsinki, Finland ORCID ID:E-mail: riitta.hanninen@metla.fi (email)
  • Kallio, Finnish Forest Research Institute, Unioninkatu 40 A, FI-00170 Helsinki, Finland ORCID ID:E-mail: maarit.kallio@metla.fi
article id 360, category Research article
Timo Kurkela, Tarmo Aalto, Martti Varama, Risto Jalkanen. (2005). Defoliation by the common pine sawfly (Diprion pini) and subsequent growth reduction in Scots pine: a retrospective approach. Silva Fennica vol. 39 no. 4 article id 360. https://doi.org/10.14214/sf.360
The foliage status in the main stem of Scots pines (Pinus sylvestris) was studied retrospectively using the needle trace method (NTM) on a stand, seriously defoliated by the pine sawfly (Diprion pini) in the 1980s. Needle density increased abruptly in the seasons following the defoliation. The strongest reduction in annual needle production occurred one year later. As a consequence of lower needle production, the annual number of attached needles decreased three to five years after the defoliation. Needle retention and the average age of attached needles tended to increase after defoliation. In analyses of covariance with the NTM variables, needle density (logarithmic transformed values) and average age of attached needles, had the highest, significant, negative relationship with radial and height increments both in the period prior to the defoliation and in the time when the trees were suffering from defoliation. The relationships between height increment and the number of needles and needle loss were positive and significant. Also radial increment had a positive relationship with the number of needles but not with needle loss. Interestingly, an abrupt increase in the needle density gave a good indication of the effects of a sudden defoliation in pines.
  • Kurkela, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: timo.kurkela@metla.fi (email)
  • Aalto, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
  • Varama, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
article id 429, category Research article
Juho Rantala. (2004). Optimizing the supply chain strategy of a multi-unit Finnish nursery company. Silva Fennica vol. 38 no. 2 article id 429. https://doi.org/10.14214/sf.429
This paper introduces a capacitated mixed integer programming (CMIP) model for solving an integrated production-distribution system design problem (PDSDP) in the seedling supply chain management (SCM) of a multi-unit Finnish nursery company. The model was originally developed from a strategic perspective in which a company desires to evaluate the expansion or closure of its facilities. Nevertheless, the model is also used for solving operational and tactical level problems by applying applicable constraints. The data were collected from the company studied. The results proved that economies of scale could be exploited in seedling production more than the company does today; Compared to the company’s current supply chain strategy with 5 nursery units producing seedlings, when other supply chain strategies were applied the number of nursery units decreased by 2–4 units, and cost savings in the supply chain varied from 11.3% to 21.3%.
  • Rantala, Finnish Forest Research Institute, Suonenjoki Research Station, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: juho.rantala@metla.fi (email)
article id 583, category Research article
Hans Fredrik Hoen, Tron Eid, Petter Økseter. (2001). Timber production possibilities and capital yields from the Norwegian forest area. Silva Fennica vol. 35 no. 3 article id 583. https://doi.org/10.14214/sf.583
How intensely should a forest be grown? This is a fundamental question in the process of formulating policy guidelines for the management of a forest area, both at the individual property level as well as at the national level. The question is related to a number of factors; the objective(s) of the forest owner, the productivity of the forestland, the initial growing stock, the accessibility within the forest, assumptions regarding future prices and costs and the required real rate of return. This paper presents an applied analysis with the objective of mapping possible future paths for the growing stock on, and timber harvest from the productive forest area in Norway. The analysis is deterministic. The regeneration strategy is a key factor for the long run development of a forest and is thus given particular attention. The analysis is restricted to deal with timber production only and maximisation of the net present value of the forest area is used as the objective function. The required real rate of return is varied and used as the driving force to find the best (optimal) level of intensity in silvicultural management and thus optimal paths for harvesting and growing stocks.
  • Hoen, Agricultural University of Norway, Dept. of Forest Sciences, P.O. Box 5044, N-1432 Ås, Norway ORCID ID:E-mail: hans.hoen@isf.nlh.no (email)
  • Eid, Agricultural University of Norway, Dept. of Forest Sciences, P.O. Box 5044, N-1432 Ås, Norway ORCID ID:E-mail:
  • Økseter, Agricultural University of Norway, Dept. of Forest Sciences, P.O. Box 5044, N-1432 Ås, Norway ORCID ID:E-mail:
article id 623, category Research article
Anders Roos, Matti Flinkman, Armas Jäppinen, Mats Warensjö. (2000). Adoption of value-adding processes in Swedish sawmills. Silva Fennica vol. 34 no. 4 article id 623. https://doi.org/10.14214/sf.623
Adding value to lumber by processing it after sawing and standard drying is one means for the sawmilling industry to increase market shares in competition with other materials, e.g. glass, steel, concrete, aluminium, and plastics. In this study the adoption patterns of value-adding processes used in Swedish softwood sawmills were analysed based on production data from 1995. About 90% of the sawmills applied a value-adding process after initial sawing and drying, and 72% of the sawmills applied two or more processes. The total share of processed sawnwood was about 40%. Important dimensions of value-adding processes are: extra drying and production of blanks for doors/windows and for furniture; surface-treatment, mainly planing, which is sometimes associated with preservation and painting; length trimming and pallet production; extra drying and production of edge-glued panels and laminated beams; and stress grading and production of building components. The association of different value-adding dimensions with location, ownership and production characteristics were investigated. The total share of value-added production were higher for private sawmills than for mills owned by forest companies or by forest owners’ associations, and it was higher for mills in southern Sweden than for sawmills in other parts of the country. Value-added share does not clearly correlate with mill size or with the dominating tree species being sawn.
  • Roos, Swedish University of Agricultural Sciences, Department of Forest Management and Products, P.O. Box 7060, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: anders.roos@sh.slu.se (email)
  • Flinkman, Swedish University of Agricultural Sciences, Department of Forest Management and Products, P.O. Box 7060, SE-750 07 Uppsala, Sweden ORCID ID:E-mail:
  • Jäppinen, Swedish University of Agricultural Sciences, Department of Forest Management and Products, P.O. Box 7060, SE-750 07 Uppsala, Sweden ORCID ID:E-mail:
  • Warensjö, Swedish University of Agricultural Sciences, Department of Forest Management and Products, P.O. Box 7060, SE-750 07 Uppsala, Sweden ORCID ID:E-mail:
article id 636, category Research article
Tuula Nuutinen, Hannu Hirvelä, Jari Hynynen, Kari Härkönen, Hannu Hökkä, Kari T. Korhonen, Olli Salminen. (2000). The role of peatlands in Finnish wood production – an analysis based on large-scale forest scenario modelling. Silva Fennica vol. 34 no. 2 article id 636. https://doi.org/10.14214/sf.636
Using the Finnish MELA model, a set of scenarios were produced and used to map the possibilities and risks surrounding the utilisation of peatlands in wood production in Finland. One of the scenarios was an estimate of allowable-cut calculated by maximising the net present value of the future revenues using a four per cent interest rate subject to non-decreasing flow of wood, saw logs and net income over a 50-year period, and net present value after the 50 year period greater or equal than in the beginning. The estimate for maximum regionally sustained removal in 1996–2005 was 68 million m3 per year – approaching 74 million m3 during the next decades. In this scenario, 14 per cent of all cuttings during the period 1996–2005 would be made on peatlands, which comprise ca. 31 per cent of the total area of forestry land. By the year 2025, the proportion of peatland cuttings would increase to over 20 per cent. The increase in future cutting possibilities on peatlands compensated for a temporary decrease in cuttings and growing stock on mineral soils. The allowable-cut effect was especially pronounced in northern Finland, where peatlands play an important role in wood production. In addition, the sensitivity of cutting possibilities for assumptions related to growth and price were analysed. The estimate of maximum sustainable yield as defined here seems to be fairly robust on the whole, except in northern Finland where the cutting scenarios were sensitive to the changes in the price of birch pulpwood. The proportion of peatland stands that are profitable for timber production depends on the interest rate: the higher the rate of interest the less peatland stands are thinned. The effect of cutting profile on future logging conditions and resulting costs were analysed in two forestry centres. If clear cuttings on mineral soils are to be cut first, an increase in future logging costs is inevitable.
  • Nuutinen, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail: tuula.nuutinen@metla.fi (email)
  • Hirvelä, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Hynynen, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Härkönen, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Hökkä, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Korhonen, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Salminen, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
article id 649, category Research article
Tord Johansson. (1999). Biomass production of Norway spruce (Picea abies (L.) Karst.) growing on abandoned farmland. Silva Fennica vol. 33 no. 4 article id 649. https://doi.org/10.14214/sf.649
Biomass production of forests has been studied for at least a century. Tree biomass is used in Sweden both as industrial raw material and an energy source. Few studies dealing with biomass yield from Norway spruce (Picea abies (L.) Karst.) growing on farmland are published. Practical recommendations are sparsely. The aim of this study was to construct dry weight equations for Norway spruce growing on farmland. Dry weight equations for fractions of Norway spruce trees were made. Biomass production was estimated in 32 stands of Norway spruce growing on abandoned farmland. The stands were located in Sweden at latitudes ranging from 58° to 64° N, and their total age varied from 17 to 54 years. A modified ‘mean tree technique’ was used to estimate biomass production; i.e. the tallest tree was chosen for sampling. The actual mean total dry weight above stump level for the 32 stands was 116 ton ha–1, with a range of 6.0 to 237.4 ton d.w. ha–1. When previous thinning removals were included, the mean biomass value was 127 ton ha–1 (6.0–262.8). In addition to estimating conventional dry weights of trees and tree components, basic density, specific leaf area, total surface area and leaf area index, among other measures, were estimated. Norway spruce biomass yields on plots subjected to different thinning were compared. The total harvested biomass was 75–120 ton d.w. ha–1 in heavy thinnings from below. Stands were thinned four to five times, with the first thinning at 23–27 years and the last at 51–64 years. The harvested biomass obtained in the first thinning was 18–38 ton d.w. ha–1. Total biomass production was 178–305 ton d.w. ha–1. Stands thinned from above supplied 71–130 ton d.w. ha–1 in total and 17–42 ton d.w. ha–1 in the first thinning. The total biomass supply was 221–304 ton d.w. ha–1. Unthinned stands produced a total of 155–245 ton d.w. ha–1.
  • Johansson, Swedish University of Agricultural Sciences, Department of Forest Management and Products, P.O. Box 7060, S-750 07 Uppsala, Sweden ORCID ID:E-mail: tord.johansson@sh.slu.se (email)

Category: Research note

article id 1330, category Research note
Hanne K. Sjølie, Hans Asbjørn Kårstad Sørlie, Bjørn Tveite, Birger Solberg. (2015). The performance of two Swedish N fertilization functions evaluated on data from Norwegian fertilization experiments. Silva Fennica vol. 49 no. 4 article id 1330. https://doi.org/10.14214/sf.1330
Highlights: The performance of two predictive Swedish fertilization growth response functions was assessed on data from Norwegian fertilization experiments; One function performed well on the full dataset, but overpredicted the growth response in spruce plots and underpredicted in pine plots; The second function performed well in pine stands, but overestimated the growth response in spruce and in total.

This study compares the responses of two Swedish 5-year predictive stand-level functions with the observed responses in 721 fertilization experiment plots in Norway fertilized with nitrogen (N). All plots are single-species consisting of Norway spruce (Picea abies (L.) H. Karst.) or Scots pine (Pinus sylvestris L.) fertilized with ammonium nitrate (AN) or urea. The correlations between the observed and the two predicted responses were 0.34–0.40 for all plots taken together. One response function performed well on average, but underestimated the response in pine plots and overestimated the response in spruce plots. The second function overpredicted the response on the full dataset, in spruce plots and old forest, but performed well in pine plots. Both functions overestimated the growth response in high-productive plots. Higher N deposition in Norway than in Sweden may count for parts of the deviations. Testing of fertilization functions on new datasets is rare, but important part of the evaluation of functions. As the functions are not well fit for predicting the growth response in spruce and high-productive plots in our sample, new functions that include N deposition are welcome.

  • Sjølie, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, NO-1432 Ås, Norway ORCID ID:E-mail: hanne.sjolie@nmbu.no (email)
  • Sørlie, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, NO-1432 Ås, Norway ORCID ID:E-mail: hans.asbjorn.sorlie@slf.dep.no
  • Tveite, Norwegian Forest and Landscape Institute, P.O. Box 115, NO-1431 Ås, Norway ORCID ID:E-mail: bjorn.tveite@skogoglandskap.no
  • Solberg, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, NO-1432 Ås, Norway ORCID ID:E-mail: birger.solberg@nmbu.no
article id 974, category Research note
Kristina Ahnlund Ulvcrona, Lars Karlsson, Ingegerd Backlund, Urban Bergsten. (2013). Comparison of silvicultural regimes of lodgepole pine (Pinus contorta) in Sweden 5 years after precommercial thinning. Silva Fennica vol. 47 no. 3 article id 974. https://doi.org/10.14214/sf.974
Highlights: Management regimes can serve different purposes such as biomass production, pulp and timber production or a combination of those; 30 tons biomass or 38–45 m3 stem volume ha–1 could be derived by schematic corridor thinning (70%) at year 20; Producing large amounts of biomass early in the rotation period does not exclude a conversion into pulp and timber production.
Early effects (stem volume, mean diameter at breast height weighted against basal area (Dgv) (Dgv), biomass and damage frequency) of different silvicultural regimes 18-19 years after direct seeding of lodgepole pine in northern Sweden were analysed. A Conventional regime, (i) precommercial thinning (PCT) to 2200 stems ha-1, was compared to: (ii) High biomass production (15 300 stems ha-1, no PCT) with and without corridor thinning at year 20, (iii) production of Large dimension trees (PCT to 1700 stems ha-1), (iv), Combined high biomass production and production of conventional round wood (PCT to 4500 stems ha-1). PCT was done 15 yrs after direct seeding for all PCT treatments. Local biomass functions showed that the regimes aiming at High biomass production displayed ca 144-157% more biomass and 134-143% more stem volume than the Conventional and Large dimension regimes (ca 21 tons and 31 m3 ha-1). Dgv for the 1000 (9.2 cm) and 2000 (8.3 cm) largest trees ha-1 appeared unaffected by regime. By schematic corridor thinning (70% of the total area) at year 20 in the High biomass regime, 27-32 tons of biomass ha-1 and 38-45 m3 ha-1 could be derived while still having a Dgv of the 1000 largest trees ha-1 of about 8 cm. Therefore, this study indicates that it is possible to produce and harvest large amounts of biomass and stem volume early in the rotation period without excluding later pulp and timber production. This initial regime comparison should be continued over time.
  • Ahnlund Ulvcrona, SLU, Forest Biomaterials and Technology, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: kristina.ulvcrona@slu.se (email)
  • Karlsson, SLU, Forest Biomaterials and Technology, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: lars.karlsson@slu.se
  • Backlund, SLU, Forest Biomaterials and Technology, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: ingegerd.backlund@slu.se
  • Bergsten, SLU, Forest Biomaterials and Technology, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: urban.bergsten@slu.se
article id 914, category Research note
Ingegerd Backlund, Urban Bergsten. (2012). Biomass production of dense direct-seeded lodgepole pine (Pinus contorta) at short rotation periods. Silva Fennica vol. 46 no. 4 article id 914. https://doi.org/10.14214/sf.914
Lodgepole pine (Pinus contorta) is a fast-growing species that is suitable for producing woody biomass in Nordic countries. Direct seeding of this species is cheaper than planting and creates dense, stable stands. The objective of this study was to quantify the stem volume and biomass production of direct seeded lodgepole pine stands grown under different site conditions with different stem densities, at an age that would permit extensive harvesting of biomass. A circle-plot inventory was performed in 16 of the oldest direct seeded lodgepole pine stands in mid-northern Sweden. Stemwood production of almost 200 m3/ha was achieved on average on the best sites, rising to about 300 m3/ha for the best circle-plots within 30 years of direct seeding despite the fact that pre-commercial thinning was made once or twice. This corresponds to 100 and 140 tons of dry weight biomass/ha, respectively. Higher stand stem densities (≥3000 st/ha) yielded more biomass with only slight reductions in diameter at breast height. The development of stem volume with respect to dominant height in direct seeded stands was becoming comparable to that in planted stands with similar spacing. It therefore seems that there is an unutilized potential for cost-effectively growing lodgepole pine in dense stands for biomass production after direct seeding. It may be possible to devise regimes for short(er) rotation forestry that would yield substantial amount of inexpensive biomass for biorefineries within a few decades.
  • Backlund, Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: ingegerd.backlund@slu.se (email)
  • Bergsten, Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: urban.bergsten@slu.se
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 7142, category Article
Seppo Ervasti. (1964). Suomen sahateollisuuden kausivaihtelu. 2. Tutkimustulokset. Acta Forestalia Fennica vol. 76 no. 2 article id 7142. https://doi.org/10.14214/aff.7142
English title: Seasonal variation in the sawmill industry of Finland II. Investigation results.

Seasonal variation in the sawmill industry of Finland was studied in an investigation based on questionnaires answered by a random sample of sawmills concerning the time period of 1958-1960. The method is described in detail in a separate article in Acta Forestalia Fennica issue 75 no. 1.

The seasonal variations in purchase of roundwood was largest in big sawmills, which purchase the main part of the timber as standing sales and buy most of the wood from the State Forest auctions at the end of September. Also, they can afford to reserve their material earlier than the smaller companies. The saw logs are mainly felled in the winter in Finland because the climatic conditions and availability of labour are best at that time. Small sawmills begin fellings a little earlier than the larger ones.

In long-transport of timber the proportion of floating decreased from 47% in 1958 to 38% in 1960. At the same time, proportion of truck transport increased from 48% to 55%. Small sawmills use almost exclusively land transport. They received almost three-fourths of their logs between January and May, because the sawing is concentrated in the first half of the year. Therefore, floating does not suit for their transport method. The larger the sawmill, the later is the seasonal peak of log deliveries. The output of the big sawmills is distributed more evenly thoughout the year. The smaller the sawmill, the quicker is the turnover of raw material and the smaller the sawlog inventories.

The seasonal variation in output is sharper at small sawmills where sawing is concentrated in the first half of the year. The seasonal peak of the early spring is due to the aim at getting the sawn wood to dry early enough for shipments in the summer. Air drying takes an average of 4 ½ months. Kiln drying is more common at the larger sawmills, and gives them more flexibility. Due to the large seasonal variation in operation, the capacity of the small mills is poorly utilized. Domestic sales of sawn wood levels up the seasonality of the deliveries. Export sales are concentrated at the end and turn of the year. Also, the seasonal peak of expenditure occurs in the winter, but that of income in the summer.

The PDF includes a summary in English.

  • Ervasti, ORCID ID:E-mail:
article id 7134, category Article
Päiviö Riihinen. (1962). Sales of newsprint in Finland, 1949-1959: models for short term forecasting. Acta Forestalia Fennica vol. 74 no. 7 article id 7134. https://doi.org/10.14214/aff.7134

Short run market forecasting is desirable both for adjusting production and for regulating the national employment policy. In this study a forecast is made for one product. The purpose of the study is to develop a short run model describing newsprint sales in Finland that will combine mathematical simplicity, accuracy of description and universality.

Two methods of selecting variables seemed to be available. According to the first, newsprint consumption is divided into components, each of which is considered separately. The second method, which proved more fruitful, starts out directly from factors influencing the publishers’ decisions in purchasing newsprint, eliminating the least significant intuitively and simultaneously determining the lags.

The models developed in this study are capable of forecasting potential consumption. Even the best models in this study are multicollinear. The further into the future a forecast is extended, the greater is the possibility that relationships between the explanatory variables will change. It is intended that the newsprint seller will profit from the models achieved by using them to forecast sales in a future period, so that he can avoid both loss of interest due to acquiring a surplus of raw material or acute shortages of raw material.

The PDF includes a summary in Finnish.

  • Riihinen, ORCID ID:E-mail:
article id 7421, category Article
Olli Heikinheimo. (1954). Taimitarhan maantieteellinen sijainti, siemenen alkuperä ja istutuskaudet. Acta Forestalia Fennica vol. 61 no. 9 article id 7421. https://doi.org/10.14214/aff.7421
English title: Geographical location of a tree nursery, seed origin and planting seasons.

Planning of large central tree nurseries, which has become topical in Finland, means that the seedlings will be used in a wide geographical area. The nursery must decide which proveniences of seeds of the different tree species it will use. This concerns also the customer that buys the seedlings. The planting and lifting of the seedlings in the nursery have to be timed so that the seedlings are in a right state of growth at the time of planting.

The growth of the seedlings can, under certain conditions, be promoted by using a slightly southerly seed provenience, and large-sized seeds. There are, however, limitations to how much the seeds can be transferred northwards. If the nursery lies much south of the planting site, the seedlings have started height growth at the time of planting. This applies especially larch (Larix sp.), Scots pine (Pinus sylvestris L.) and birch (Betula sp.), but affects less Norway spruce (Picea abies (L.) Karst.). The problem can be handled by using a cool storage space for the seedlings waiting for a delivery in the nursery.

According to an international study, seedlings grown from seeds collected in countries south from Finland usually die already during the first two years in the nursery. Within Finland the seeds can be transferred at least by two latitudes. Spruce seems to tolerate longer transfer. Seed orchards should be planted south of the seed’s origin to ensure better yield and better quality seeds.

The Silva Fennica issue 61 was published in honour of professor Eino Saari‘s 60th birthday.
The PDF includes a summary in German.

  • Heikinheimo, ORCID ID:E-mail:
article id 7404, category Article
Valter Keltikangas. (1950). Suotyyppien liiketaloudellisesta ojituskelpoisuusjärjestyksestä. Acta Forestalia Fennica vol. 58 no. 4 article id 7404. https://doi.org/10.14214/aff.7404
English title: Drainability of different peatland types from an economic perspective.

One of the factors that influence if a peatland is suitable for draining is the time required until fellings bring income, even if it the discounting calculations has uncertainties. This article discusses the factors that affect the economic profitability of draining peatlands.

The profitability of draining increases the more the yield or increase of the yield exceeds the costs of draining. Estimation of the yield is in Finland based on the peatland type, which reflects production capacity of the site. In addition, the growing stock of the site can vary in peatlands within same peatland type. The density and size of ditches affects the draining costs. Thus, productivity based on a peatland type alone does not describe well enough the drainability of a peatland area.

In Finnish classification of site quality of the peatlands, the treeless bogs and rich fens have been given too high a class compared to well stocked spruce swamps and pine swamps. Also, the drainability of two spruce and pine swamps can differ markedly in economic point of view if the tree’s quality, volume and ability to recover differ. The article discusses different methods to assess profitability of draining that have been descibed in the previous studies. It is suggested that the classification of peatlands by their drainability should be more selective.

The PDF includes a summary in German.

  • Keltikangas, ORCID ID:E-mail:
article id 7390, category Article
Onni Pohjakallio, Olli Vaartaja. (1948). Über Vorkommen und Sporenbildung von Coleosporium Melampyri Kleb. auf verschiedenen Standorten und Wirtspflanzen. Acta Forestalia Fennica vol. 55 no. 2 article id 7390. https://doi.org/10.14214/aff.7390
English title: Occurrence and spore production of Coleosporium melanpyri Kleb. (pine needle rust) on different sites and host plants.

Department of plant pathology of University of Helsinki conducted studies in the surrounding forests of Viikki test farm and on the Hyytiälä forest training station to find about occurrence and spore production of pine needle rust.

The damages have been minor. Most often the infection did not cause yellowing of the needles, only individual needles might have dried up. There were no dead young trees.

The spore production was strongest at the more fertile sites, with abundant occurrence of cow-wheat (Melanpyrum spp.). The infection caused more harm on the cow-wheat than on the pines. In many cases the foliage died prematurely. Melanpyrum spp. were more strongly infected on sites with more light. However, there was no difference found with the fertility of the site.

The PDF contains a summary in Finnish. 

  • Pohjakallio, ORCID ID:E-mail:
  • Vaartaja, ORCID ID:E-mail:
article id 7367, category Article
Esko Kangas. (1942). Karistuslämmön vaikutuksesta männyn siemenen karisemiseen ja itämiseen. Acta Forestalia Fennica vol. 50 no. 14 article id 7367. https://doi.org/10.14214/aff.7367
English title: Effect of seed extracting temperature on extraction and germination of Scots pine seeds.

Temperatures needed in extracting Scots pine (Pinus sylvestris L.) seeds is relatively high, however, there is little information on its effect on germination of the seeds. This survey aimed at studying how different temperatures affect both extraction result and germination of Scots pine seeds. Comparisons between different temperatures (20, 30, 40, 50, 60 and 70 ºC) were made from cones collected from same sample trees, three trees in total.

Temperatures 20 and 30 ºC resulted in incomplete opening of the cones, and gave thus smaller amount of seeds. Complete extraction requires at the least the temperature of 40 ºC. The result is slightly better in 50 ºC, but germination of the seeds is little lower. Temperatures 60 and 70 ºC improve the results, but in the cost of germination. The main reason for lower germination percentage was that the higher temperatures release more empty and defective seeds from the cones. Results of different sample trees were different due to, for instance, quality and size of cones. Higher temperatures accelerated the extraction. According to the study, perfect extraction in 40 ºC requires longer extraction time than when the temperature of 50 ºC is used. In practice, 50 ºC temperature or even little higher temperatures can be used when the extraction time is shorter. Decessive factors in choosing the temperature would be the humidity of cones and length of extraction time.

The PDF includes a summary in German.

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

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

  • de Reffye, ORCID ID:E-mail:
  • Barthélémy, ORCID ID:E-mail:
  • Blaise, ORCID ID:E-mail:
  • Fourcaud, ORCID ID:E-mail:
  • Houllier, ORCID ID:E-mail:
article id 5592, category Article
Ari Talkkari. (1996). Regional predictions concerning the effects of climate change on forests in southern Finland. Silva Fennica vol. 30 no. 2–3 article id 5592. https://doi.org/10.14214/sf.a9237

A gap-model was used with forest inventory data in taking ground-true site, soil and tree characteristics into account in predicting the effects of climate change on forests. A total of 910 permanent sample plots established in the course of national forest inventory (NFI) in Finland and located on mineral soil sites in southern Finland were selected as the input data. The climatological input used in the simulations consisted of interpolated means of and deviations from long-term local temperature and precipitation records. The policy-oriented climate scenarios of SILMU (Finnish Research Programme on Climate Change) were used to describe the climate change. The temperature changes in the climate scenarios were increases of ca. +1.1 °C (low), +4.4 °C (medium) and +6.6 °C (high) compared to the current climate in 110 years. The simulation period was 110 years covering the time years 1990–2100.

Southern Finland, divided into fifteen forestry board districts, was used as the study region. Regional development of stand volume, cutting yield, and total wood production of forests under different climate scenarios were examined. The annual average growth in simulations under current climate was close to that observed in NFL Forests benefited from a modest temperature increase (Scenario 2), but under Scenario 1 the growing stock remained at a lower level than under the current climate in all parts of the study region. In wood production and cutting yield there were regional differences. In the southern part of the study regional wood production under Scenario 1 was ca. 10% lower than under the current climate, but in the eastern and western parts wood production was 5–15% higher under Scenario 1 than under the current climate. The relative values of total wood production and cutting yield indicated that the response of forests to climate change varied by geographical location and the magnitude of climate change. This may be a consequence of not just varying climatic (e.g. temperature and precipitation) and site conditions, but of varying responses by different kind of forests (e.g. forests differing in tree species composition and age).

  • Talkkari, ORCID ID:E-mail:
article id 7195, category Article
Martti Hertz. (1925). Niinipuun uudistumisesta Suomessa. Acta Forestalia Fennica vol. 29 no. 5 article id 7195. https://doi.org/10.14214/aff.7195
English title: Regeneration of small leaved lime in Finland.

The northern range of small leaved lime (Tilia cordata Mill.) in Finland has remained the same since the end of 1800s, but according to the studies of subfossiles of lime found in peatlands, the northern limit has once been higher than at the present. The northernmost natural specimens of the species in Reisjärvi do not produce seed, and are therefore probably a relict. The article includes a review on the distribution of the species in Finland and its capacity to regenerate. The natural regeneration of lime in Finland is at present very rare. The species has lost its ability to sexual reproduction, but reproduces readily vegetatively.

The PDF includes a summary in German.

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

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

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

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

  • Hytönen, ORCID ID:E-mail:
  • Rossi, ORCID ID:E-mail:
  • Saarsalmi, ORCID ID:E-mail:
article id 5550, category Article
Jyrki Hytönen. (1995). Effect of repeated fertilizer application on the nutrient status and biomass production of Salix ’Aquatica’ plantations on cut-away peatland areas. Silva Fennica vol. 29 no. 2 article id 5550. https://doi.org/10.14214/sf.a9201

The effects of repeated fertilizer treatment on biomass production and nutrient status of willow (Salix ’Aquatica’) plantations established on two cut-away peatland areas in western Finland were studied over a rotation period of three years. Comparisons were made between single fertilizer applications and repeated annual fertilization.

The annually repeated fertilizer application increased the amounts of acid ammonium acetate extractable phosphorus and potassium in the soil as well as the concentrations of foliar nitrogen, phosphorus and potassium compared to single application. Depending on the fertilizer treatment and application rate, annual fertilizer application resulted in over two times higher biomass production when compared to single fertilizer application over a three-year rotation period. The effect of phosphorus fertilizer application lasted longer than that of nitrogen. The optimum fertilization regime for biomass production requires that nitrogen fertilizer should be applied annually, but the effect of phosphorus can last at least over a rotation of three years. Potassium fertilizer treatment did not increase the yield in any of the experiments during the first three years. The leafless, above-ground yield of three-year-old, annually NP-fertilized willow plantations was 9.5 t ha-1 and the total biomass, including stems, leaves, roots and the stump, averaged 17 t ha-1.

  • Hytönen, ORCID ID:E-mail:
article id 5544, category Article
Jyrki Hytönen. (1995). Effect of fertilizer treatment on the biomass production and nutrient uptake of short-rotation willow on cut-away peatlands. Silva Fennica vol. 29 no. 1 article id 5544. https://doi.org/10.14214/sf.a9195

The effects of fertilized treatment on the soil nutrient concentrations, biomass production and nutrient consumption of Salix x dasyclados and Salix ’Aquatica’ were studied in five experiments on three cut-away peatland sites in western and eastern Finland during three years. Factorial experiments with all combinations of N (100 kg ha-1 a-1), P (30 kg ha-1 a-1) and K (80 kg ha-1 a-1) were conducted.

The application of P and K fertilizers increased the concentrations of corresponding extractable nutrients in the soil as well as in willow foliage. N-fertilization increased foliar nitrogen concentration. An increase in age usually led to decreases in bark and wood N, P and K concentrations and increases in bark Ca concentrations. N-fertilization increased the three-year biomass yield 1.5–2.7 times when compared to control plots. P-fertilization increased the yield only in those experimental fields whose substrates had the lowest phosphorus concentration. K-fertilization did not increase the yield in any of the experimental fields. The highest total biomass yield of NPK-fertilized willow after three growing seasons, 23 t ha-1, was distributed in the following way: wood 42%, bark 19%, foliage 17%, stumps 6% and roots 16%. As the yield and stand age increased, more biomass was allocated in above-ground wood. Three-year-old stands (above-ground biomass 18 t ha-1) contained as much as 196 kg N ha-1, 26 kg P ha-1, 101 kg K ha-1, 74 kg Ca ha-1 and 37 kg Mg ha -1. By far the highest proportion of nutrients accumulated in the foliage. The bark and wood contained relatively high proportions of calcium and phosphorus. With an increase in age and size, the amount of nitrogen and potassium bound in one dry-mass ton of willow biomass decreased while that of phosphorus remained unchanged.

  • Hytönen, ORCID ID:E-mail:
article id 5542, category Article
Leena Ryynänen, Anneli Viherä-Aarnio. (1995). Growth, crown structure and seed production of birch seedlings, grafts and micropropagated plants. Silva Fennica vol. 29 no. 1 article id 5542. https://doi.org/10.14214/sf.a9193

Growth, crown structure, flowering and seed production of silver birch (Betula pendula Roth) seedlings, grafts and micropropagated plants was compared during four years in a polythene greenhouse experiment. The growth of the seedlings was clearly the most vigorous and that of the grafts the weakest, the micropropagated plants being intermediate. The seedlings had the highest and the grafts the lowest number of branches before cutting the tops of the plants, but the differences between the material types were no more significant after cutting the tops. The grafts had significantly shorter and thinner branches than the seedlings and the micropropagated plants, whereas the differences in branch length and branch thickness between the latter two groups were not significant. The grafts started flowering at the age of two years, one year earlier than the other two types of material. At the age of four years the micropropagated plants had abundant seed production, about 75% of that of the seedlings and about two times higher than that of the grafts. Thus, the micropropagated plants can be used instead of grafts when establishing polythene greenhouse seed orchards of birch.

  • Ryynänen, ORCID ID:E-mail:
  • Viherä-Aarnio, ORCID ID:E-mail:
article id 5539, category Article
Tore Skrøppa. (1994). Impacts of tree improvement on genetic structure and diversity of planted forests. Silva Fennica vol. 28 no. 4 article id 5539. https://doi.org/10.14214/sf.a9179

After a presentation of basic biodiversity concepts, reviews are made of studies reporting genetic implications of tree improvement activities: seed treatments, seedling production, provenance transfers, plus tree selection, seed production in seed orchards and progeny testing.

Several of the activities may influence the genetic structure and diversity of the planted forests. The general conclusion is, however, that planted forests are at least as genetically diverse as the natural stands that they replace. The diversity in forest management and use is best assurance for the future adaptability of the forests.

  • Skrøppa, ORCID ID:E-mail:
article id 5538, category Article
Anneli Viherä-Aarnio, Leena Ryynänen. (1994). Seed production of micropropagated plants, grafts and seedlings of birch in a seed orchard. Silva Fennica vol. 28 no. 4 article id 5538. https://doi.org/10.14214/sf.a9178

Seed production of micropropagated plants, seedlings and grafts of Silver birch (Betula pendula Roth) in a polyethylene greenhouse experiment was followed for five years. The grafts started flowering and seed production at the age of two years, one year earlier than other two types of material. At the age of three the seed production of both micropropagated plants and seedlings was already more than two times higher than that of the grafts. Variation between the clones was high and plant type x clone interaction was significant. At the age of four, in 1993, seed production was high in all three types of material. Seed production of the micropropagated plants was two times higher than that of the grafts but about 75% of that of the seedlings. In 1994 seed production of all three plant types was very low, which shows large variation between different years. The early development of the plant material types suggests that micropropagated plants have higher seed production than grafts and could well be used instead of grafts in polythene greenhouse seed orchards.

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

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

  • Honkanen, ORCID ID:E-mail:
article id 5519, category Article
Jyrki Kangas, Jari Karsikko, Laura Laasonen, Timo Pukkala. (1993). A method for estimating the suitability function of wildlife habitat for forest planning on the basis of expertise. Silva Fennica vol. 27 no. 4 article id 5519. https://doi.org/10.14214/sf.a15680

In the method presented in this study, a group of experts evaluate, in a pairwise manner, a set of forest areas with respect to the game species considered. On the basis of these comparisons, relative priorities of forest areas are estimated using the eigenvalue technique. Using regression analysis, a habitat suitability function is estimated in which the priority is predicted by measures already familiar in forest planning. As a case study, a habitat suitability function was estimated for black grouse (Tetrao tetrix, Lururus tetrix L.). The function is applicable in forestry planning carried out using modern planning techniques.

The PDF includes an abstract in Finnish.

  • Kangas, ORCID ID:E-mail:
  • Karsikko, ORCID ID:E-mail:
  • Laasonen, ORCID ID:E-mail:
  • Pukkala, ORCID ID:E-mail:
article id 5512, category Article
Christian Messier, Pasi Puttonen. (1993). Coniferous and non-coniferous fine-root and rhizome production in Scots pine stands using the ingrowth bag method. Silva Fennica vol. 27 no. 3 article id 5512. https://doi.org/10.14214/sf.a15673

Coniferous and non-coniferous fine root and rhizome production was measured after one growing season using the ingrowth bag method in Scots pine (Pinus sylvestris L.) stands differing in ages from 7 to 105 years in Southern Finland. Total fine-root production decreased from the 7-year to 20-year-old stands, and then increased slightly in the 85- to 105-year-old stands. Most of the total fine-root biomass in the youngest age groups came from non-conifer species, whereas most of the total fine-root biomass in the three older age groups came from conifer species. The maximum coniferous fine-root production was found to occur at crown closure in the 11- to 13-year-old stands. Rhizome production was the lowest and highest in the 20- and 85- to 105-year-old stands, respectively. The increase in rhizome production in the 85- to 105-year-old stands was associated with an abundant understory cover of Vaccinium myrtillus and V. vitis-idaea and an increase in light penetration. The ingrowth bag method was found to be useful in assessing the relative fine-root production among species-group and successional stages of Scots pine stands.

The PDF includes an abstract in Finnish.

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

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

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

  • Heiskanen, ORCID ID:E-mail:
article id 5477, category Article
Martti Saarilahti. (1992). Skidding by sulky - a literature study. Silva Fennica vol. 26 no. 2 article id 5477. https://doi.org/10.14214/sf.a15638

Speed and load sizes presented in three study reports on sulky skidding were compared with estimates based on ergonomic models. Speed and load size estimates were closely correlated with the observed values, when a 400 W energy expenditure of the subject was used. This corresponds to less than half of his submaximal oxygen intake and matches well with the heart rate given in one of the time studies. It seems possible to develop methods for evaluating the work pace/production rate for sulky skidding in varying terrain conditions.

The PDF includes an abstract in Finnish.

  • Saarilahti, ORCID ID:E-mail:
article id 5462, category Article
Wladyslaw Chalupka. (1991). Usefulness of hormonal stimulation in the production of genetically improved seeds. Silva Fennica vol. 25 no. 4 article id 5462. https://doi.org/10.14214/sf.a15620

Application of growth regulators, primarily gibberellins, has become an efficient method of flowering regulation in many coniferous forest trees. In this paper some results are discussed with respect to various genetic processes in seed orchards. It is concluded that there are still several unsolved problems in the regulation of flowering in forest seed orchards. These problems are related to different genetic processes occurring in the seed orchards and they should be taken into account in endeavouring to produce genetically improved seeds. 

  • Chalupka, ORCID ID:E-mail:
article id 5459, category Article
Pertti Pulkkinen. (1991). Crown form and harvest increment in pendulous Norway spruce. Silva Fennica vol. 25 no. 4 article id 5459. https://doi.org/10.14214/sf.a15617

Crown characteristics and the distribution of three years’ (1986–88) biomass production of 20 pendulous Norway spruce (Picea abies f. pendula (Lawson) Sylvén) trees with heritable narrow crown and 15 normal-growned spruces (Picea abies (L.) H. Karst.) were studied in a 19-year-old mixed stand.

The form of the crown is conical in normal-crowned trees, columnar and narrow in pendulous trees. The partitioning of aboveground biomass to stems during the studied 3-year period was significantly higher in pendulous (0.281) than in normal-crowned trees (0.255) and also the ratio between growth of stemwood and growth of needle biomass during three years was higher in pendulous trees (0.67 g g-1) than in normal-crowned trees (0.52 g g-1). The needle biomass was distributed higher in the crown in pendula than in normal-crowned trees and they had a higher needle biomass/branchwood biomass ratio than normal trees. The difference in harvest increment between the two crown types are mostly due to the significantly lower branchwood biomass values in pendulous than in normal-crowned trees. The higher needle ’efficiency’ in pendulous trees is probably connected with high partitioning of needle biomass to the upper part of the crown in pendulous trees.

The PDF includes an abstract in Finnish.

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

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

The PDF includes an abstract in Finnish.

  • Kuuluvainen, ORCID ID:E-mail:
article id 5347, category Article
Timo Kuuluvainen, Markku Kanninen, Juha-Pekka Salmi. (1988). Tree architecture in young Scots pine: properties, spatial distribution and relationships of components of tree architecture. Silva Fennica vol. 22 no. 2 article id 5347. https://doi.org/10.14214/sf.a15504

The architecture of Scots pine (Pinus sylvestris L.) was studied in an eight-year-old progeny test. The measurements included characteristics of crown structure, spatial distribution of shoots and yield components. The spatial distribution of shoots showed striking between-tree differences, and two extreme distribution patterns were detected. One represented a non-layered structure with a vertically relative even shoot distribution, and the other a layered structure with a vertically highly uneven shoot distribution.

Close correlations existed between several components of tree architecture and it is suggested that changes in the phenotypic architecture in Scots pine follow an epigenetic pattern, which enables the prediction of adaptational changes in structural components. The structural characteristics related to high above-ground biomass were a long crown, high total shoot length, high number of branches per whorl and big shoots of low needle density occupying a big share of the crown volume.

The PDF includes a summary in Finnish.

  • Kuuluvainen, ORCID ID:E-mail:
  • Kanninen, ORCID ID:E-mail:
  • Salmi, ORCID ID:E-mail:
article id 5342, category Article
Ilari Lumme, Timo Törmälä. (1988). Selection of fast-growing willow (Salix spp.) clones for short-rotation forestry on mined peatlands in northern Finland. Silva Fennica vol. 22 no. 1 article id 5342. https://doi.org/10.14214/sf.a15499

Possibilities of developing suitable willow (Salix spp.) clones for short-rotation forestry on mined peatlands in the north-western area of Finland were studied in a field experiment in which 300 willow clones were tested during 1985–87. Most of the tested clones started to grow from cuttings on limed and fertilized peat soil. Salix viminalis L. clones of southern origin had a higher leafless above ground biomass production than the well adapted control clone and the local Finnish willows, but their winter hardiness was not satisfactory. The growth habit of some southern willows was also better than that of the control clone. It was also possible to select clones with good sprouting capacity. There were few Salix myrsinifolia Calisb. clones of Finnish origin, which had better cold tolerance than all other willows tested and higher biomass production than that of the control clone. The most critical factor to be selected for this is the optimal combination of winter hardiness and biomass production. This is attempted by selecting clones on the basis of this experiment for a breeding program.

The PDF includes a summary in Finnish.

  • Lumme, ORCID ID:E-mail:
  • Törmälä, ORCID ID:E-mail:
article id 5314, category Article
M. Saarilahti, E. Bakena, G. Mboya, T. Minja, T. Ngerageze, J. Ntahompagaze. (1987). Studies on Tanzanian forest work. Silva Fennica vol. 21 no. 2 article id 5314. https://doi.org/10.14214/sf.a15471

Four teams of two workers were time-studied in clearcutting of a cypress plantation and three teams in sulky skidding. The heart rate was recorded every 30 s. The average heartrate in timber cutting was 117.5 ± 13.4 P/min, and it was mainly dependent on worker’s working capacity. Average work load index was 41 ± 3% when working at 97% performance. The production rate was then 2.5 m3/h (crew). In sulky skidding the heart rate was lower, 106 ± 1.1 P/min, as well as the work load (WLI 30 ± 1%) and performance rating (87%). The low production rate (1.1 m3/h) (crew)) over 45 m distance is mainly due to under-dimensioned load size. The energy expenditure in timber cutting was 21.4 kJ/min and in sulky skidding 16.3 kJ/min. Daily energy expenditure was 15.0 MJ/d, and most of the timber cutters belonged to the class ”exceptionally active”.

The PDF includes an abstract in Finnish.

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

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

The PDF includes an abstract in Finnish.

  • Saarilahti, ORCID ID:E-mail:
  • Ole-Meiludie, ORCID ID:E-mail:
article id 5292, category Article
Ryoichi Handa. (1986). On the principles of Japanese forest policy since 1950. Silva Fennica vol. 20 no. 4 article id 5292. https://doi.org/10.14214/sf.a27748

In Japan many governmental projects have been promoted during 35 years since 1950, which were most active in the history of our forestry and wood industry. They were pushed forward for and by high economic growth. This article refers to the development of our forest policy and projects in those days. But as for the future of the forest economics, it is an urgent question to develop the comparative study between every nation’s experience. In order to contribute to this problem, the forest policy is divided into three fields and experiences are discussed.

  • Handa, ORCID ID:E-mail:
article id 5260, category Article
The Forest 2000 Programme sub-commitee. (1986). The Forest 2000 Programme in Finland. Silva Fennica vol. 20 no. 1 article id 5260. https://doi.org/10.14214/sf.a15439

The Forest 2000 Programme is a long-term programme for forestry and the forest industries in Finland. It attempts to obtain a better integration of timber production and other forms of forest use. The total annual cut is to be increased by 15 million m3 by the year 2010. This is almost one third greater than the level during the first few years of the 1980’s. In order to achieve the cutting targets, the cut area will have to be increased by almost one third by the turn of the century. The area of thinnings will experience the greatest increase. Considerable changes are proposed in silvicultural and basic improvement work. According to the programme, the growth of the raw-material base and the consumption of the wood-based products will permit an annual increase of about 3% in the production of the forest industries as a whole until the end of the century. This would be the same as the target growth rate of the GNP.

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  • The Forest 2000 Programme sub-commitee, ORCID ID:E-mail:
article id 5244, category Article
Juha Lappi, Markku Siitonen. (1985). A utility model for timber production based on different interest rates for loans and savings. Silva Fennica vol. 19 no. 3 article id 5244. https://doi.org/10.14214/sf.a15423

The paper discusses the evaluation of timber production policies with different income (timber drain) schedules. Special attention is given to the temporal smoothness of the income flow. A utility model is formulated in which the objective is to maximize a fixed consumption pattern, and money can be saved and borrowed at different interest rates. We thus have smoothness requirements only for consumption, the capital market then determines the smoothness of the optimal income flow. Present discounted value and maximization of even income flow criteria are special cases of the utility model. Consumption can be maximized by linear programming. A sample problem is presented.

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  • Lappi, ORCID ID:E-mail:
  • Siitonen, ORCID ID:E-mail:
article id 5145, category Article
Torleif Bramryd. (1981). Environmental effects of heavy metals distributed from power plants. Silva Fennica vol. 15 no. 4 article id 5145. https://doi.org/10.14214/sf.a15372

Increased prices on oil have resulted in the search for alternative energy sources, e.g. coal, peat, biomass, different types of waste. Combustion especially of waste, coal and peat emits large quantities of air pollutants such as heavy metals but also harmful organic substances. Heavy metals are not easily separated from the smoke, and the concentrations are often high in the emissions even with advanced fly-ash separators.

Ecological investigations carried out around a coal burning power plant in Finland using mosses and pine needles as parameters are presented in the paper. Increased concentrations of Pb, Cd, Cr, Ni, Cu and V have been found near the plant. Often a clear gradient was found with increased concentrations at decreased distance from the power plant.

  • Bramryd, ORCID ID:E-mail:
article id 5101, category Article
Ilpo Tikkanen. (1981). Effects of public forest policy in Finland. Silva Fennica vol. 15 no. 1 article id 5101. https://doi.org/10.14214/sf.a15042

The purpose of the present study is to explore the applicability of some methodological approaches to empirical policy analysis in evaluating the effectiveness of public forest policy. From the perspective of effectiveness analysis we can distinguish in forest policy, aiming at the promotion of timber production, two principal objective levels in forestry: the quantity of silvicultural investments and their allocation and the quantity (sufficiency) together with the structure of timber supply. This paper is restricted to the exploration of the effect of forest policy measures directed to silvicultural investments in private forestry. First, the effects of state subsidies in silvicultural investments are analysed. The analysis is macro analysis of quantitative forest policy means, in which aggregated time series data are used as study material. Second, an attempt is made to provide a causal interpretation of the impacts of qualitative forest policy means at the woodlot level. This micro analysis utilizes an approach characteristic to the behavioural sciences.

It is concluded that like quantitative forest policy means the qualitative means, coupled with the activities of the forest promotion organizations, play a significant role in attaining the timber production goals. Of these, the professional advice given by forestry experts, has a direct effect on silvicultural activities. Extension and training activities have an indirect effect by increasing the willingness of forest owners to employ experts on their woodlots.

  • Tikkanen, ORCID ID:E-mail:
article id 4981, category Article
Seppo Kellomäki, Pertti Hari, Pekka Kauppi, Eero Väisänen. (1977). Production of structural matter by a plant community in successional environment. Silva Fennica vol. 11 no. 4 article id 4981. https://doi.org/10.14214/sf.a14835

The structural matter production of selected plant species of a ground cover community was determined in relation to light available for photosynthesis. The resulting functions were applied in a situation where the light reaching the ground cover was controlled by the dynamics of the tree crown strata, and the occurrence of different plant species at different stages of succession was determined on the basis of their production of structural matter in actual light conditions. The possible strategies involved in adaptation to a successional environment have been discussed.

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  • Kellomäki, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
  • Kauppi, ORCID ID:E-mail:
  • Väisänen, ORCID ID:E-mail:
article id 4973, category Article
Olli Saastamoinen. (1977). Economics of forest uses in Finnish Lapland. Silva Fennica vol. 11 no. 3 article id 4973. https://doi.org/10.14214/sf.a14824

The object of the study was to give a tentative indication of the realized economic significance of the principal forest (forestry land) uses in Finnish Lapland. Data concerns the years of the 1970s. Nowadays timber harvesting generates a major part of the total value of production. Recreation (tourism) is in second place. Reindeer husbandry, collection of berries and mushrooms and hunting together produce, in the best years, an output value which is about one fifth of that of timber harvesting. Non-timber uses together produce a rather significant portion on the total value of the integrated forestry output.

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  • Saastamoinen, ORCID ID:E-mail:
article id 4920, category Article
Peitsa Mikola. (1975). Turvetuotannosta vapautuvan maan metsittäminen. Silva Fennica vol. 9 no. 2 article id 4920. https://doi.org/10.14214/sf.a14776
English title: Afforestation of bogs after industrial exploitation of peat.

Peat industry is rapidly expanding in Finland. Consequently, during next decades peat will be removed from thousands of hectares. Because timber production probably is the most rational use of this area after the peat production has ended, some experiments of afforestation of such areas have already been conducted. This article reports results of two experiments which were started in Kihniö, Western Finland, in 1953 and 1964.

In the first experiment fertilization with wood ash proved very effective whereas seeding and planting without fertilization resulted in almost complete failure. In the second experiment, interplanting with grey alder (Alnus glutinosa L. Gaertn.) greatly promoted the growth of Scots pine (Pinus sylvestris L.). The effect of slight fertilization lasted a few years only. The reasons for the remarkable effect of alder need further research. Although alder is known as a nitrogen-fixing plant, its beneficial effect was most clearly seen in the K and P contents of pine needles. Inoculation with mycorrhizal fungi was beneficial but not necessary. Experiments hitherto show that afforestation of bogs after peat removal is possible although some additional measures like fertilization or interplanting with alder may be needed.

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  • Mikola, ORCID ID:E-mail:
article id 4918, category Article
Pekka Kilkki, Raimo Pökälä, Markku Siitonen. (1975). Metsätalousyksikön puuntuotannon suunnittelu lineaarista ohjelmointia käyttäen. Silva Fennica vol. 9 no. 2 article id 4918. https://doi.org/10.14214/sf.a14762
English title: Linear programming in the planning of timber production in a forestry unit.

The planning of timber production in a forestry unit is divisible into two phases. In the first phase, planning provides the decision-maker with a number of possible timber production policies; these policies define the production possibility boundary. After the decision-maker has chosen one of these policies, planning moves to the second phase, in which a detailed programme is prepared with a view to meeting the requirements of the timber production policy accepted. The paper indicates one possibility of solving these two tasks simultaneously. In the first phase, the solution of the primal linear programming problem is employed and in the second phase the respective dual or shadow price solution.

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  • Kilkki, ORCID ID:E-mail:
  • Pökälä, ORCID ID:E-mail:
  • Siitonen, ORCID ID:E-mail:
article id 4906, category Article
Lasse Lovén. (1974). Maisemanhoitomallien käyttö metsätalouden maan aluevaraussuunnittelussa. Silva Fennica vol. 8 no. 3 article id 4906. https://doi.org/10.14214/sf.a14750
English title: Regional landscape planning of forest areas.

The study deals with economic significance of forest landscape planning models used in regional planning in Finland. The »judge»-method is used among professional foresters working on private forestry boards in Southern Finland to define their view of what would be moderate level of costs of landscape management for private forest owners. A sample of 154 forest professionals working in district forestry boards in Southern Finland was sent a sociological questionnaire.

It was possible to form three hierarchical moderation classes by statistical grouping of judgement distributions. Prolongations in rotation ages and restrictions concerning ditching of forested bogs, forest read building and clear-cutting were considered the most immoderate models. Rather or wholly insignificant were evaluated such management models, which mean restrictions in »old fashioned» methods or which are already used in practice.

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  • Lovén, ORCID ID:E-mail:
article id 7013, category Article
Lauri Ilvessalo. (1917). Tutkimuksia mäntymetsien uudistumisvuosista Etelä- ja Keski-Suomessa. Acta Forestalia Fennica vol. 6 no. 2 article id 7013. https://doi.org/10.14214/aff.7013
English title: Studies on the regeneration years of Scots pine forests in Southern and Central Finland.

The success of natural regeneration of Scots pine (Pinus sylvestris L.) is dependent on the amount and quality of seeds produced in each year. While seed production of Scots pine in Northern Finland is well known, there is little information about frequency of good seed years in Southern and Central Finland. The success of regeneration of Scots pine was studied by defining from the growth rings of felled sample trees in which year they started to grow. The aim was to choose sample trees so that they would form a continual series from seedlings to 100 years old trees. In the material there was too little sample trees from certain years. However, within the period of 1827-1910 it could be identified 13 good regeneration years of pine in Southern Finland. According to the study, pine has regenerated very well every 6th year and at least moderately well every 4th year. When compared to the previous studies made in Northern Finland, part of the good regeneration years seems to be same both in Northern and Southern Finland. Regeneration of Scots pine is affected also by the type and condition of the site.

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  • Ilvessalo, ORCID ID:E-mail:
article id 4868, category Article
Mikko Tormilainen. (1972). Havaintoja Oitin siemenviljelyksen mäntykloonien kukinnasta ja käpysadosta. Silva Fennica vol. 6 no. 2 article id 4868. https://doi.org/10.14214/sf.a14671
English title: Studies of flowering and cone crop in a seed orchard of Scots pine.

Male and female flowering, cone crop, and some vegetative characteristics were studied in grafts 10 to 16 years of age in a clonal seed orchard of Scots pine (Pinus sylvestris L.). Genetic variation was found between clones in flowering as well as in cone production. Clone evaluation resulted in similar classifications of clones in different years. A regression analysis showed that crown size clearly increased but previous height growth slightly decreased flowering and cone production. The percentage of pollinated female strobili did not differ between clones.

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  • Tormilainen, ORCID ID:E-mail:
article id 4855, category Article
Peitsa Mikola. (1971). Puuntuotannon ja metsien virkistyskäytön koordinointi Saksan liittotasavallassa. Silva Fennica vol. 5 no. 4 article id 4855. https://doi.org/10.14214/sf.a14657
English title: Integration on timber production and forest recreation in the German Federal Republic.

The article is a report of a study tour of five Finnish foresters in Germany on September 27 – October 2. 1971. As in most industrial countries, the recreation use of forests is rapidly expanding and, therefore, its needs are considered in the management of forests. Two examples of intensively used recreation forests are described, Schönbuch near Stuttgart and the Bavarian Forest National Park at the Czechoslovakian border. These forests are effectively used for both timber production and recreation at the same time. Some other effects of urbanization on forests also are discussed in the article.

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  • Mikola, ORCID ID:E-mail:
article id 4828, category Article
Juhani Numminen. (1970). Pellonvaraussopimusten alaisten peltojen metsitys. Silva Fennica vol. 4 no. 4 article id 4828. https://doi.org/10.14214/sf.a14617
English title: Afforestation of agricultural land under soil bank contracts.

Under the soil bank act, which took effect in 1969, 85,000 hectares of agricultural land were withdrawn from agricultural production in order to cut down the heavy surpluses of grain and butter in Finland. The farmers have a possibility to afforest their soil bank land partly on public funds, and if they choose to do so they receive a compensation of 250 Fmk for 15 years, instead of the nine years which is the maximum duration of a soil bank contract.

The study involved interviewing of 136 farmers sampled from the total of 13,368. The farmers were planning to afforest a total of 18,600 ha by the end of 1972. The main species were birch (Betula sp.) 40%, Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) both 30%. The main reasons (mentioned by 65% of the farmers) for afforestating the soil bank land were the unfavourable conditions for agriculture. On the other hand, 43% of those who had decided not to afforest felt that their land is too good to be planted with trees. One fifth of those not afforesting said that they themselves would not benefit from the afforestation and therefore were not interested in investing in forestry. The attitudes of the farmers seem to have also influenced their decision on afforestation. Those who had taken a positive decision on afforestation appeared to take more positive attitude in regard to forestry than other farmers.

The soil bank act does not seem to solve permanently Finland’s problem of the surpluses of agricultural products since the soil bank farmers planned to revert two thirds of the soil bank land under cultivation on the expiration of the soil bank act.

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  • Numminen, ORCID ID:E-mail:
article id 7527, category Article
August Renvall. (1913). Die periodischen Erscheinungen der Reproduktion der Kiefer an der polaren Waldgrenze. Acta Forestalia Fennica vol. 1 no. 2 article id 7527. https://doi.org/10.14214/aff.7527
English title: The periodic variation of the regeneration of pine (Pinus sylvestris) at the polar tree line.

The study deals with the preconditions for natural regeneration of the pine at the polar tree line in northern Finland and Sweden. The data has been collected in three summers from 1909 to 1911 in areas of Inari and Utsjoki in Finland and Kaaresuvanto, Jukkasjärvi und Pajala in Sweden. The yearly variation of seed production of pine is studied and compared with the age of the stand, site factors and weather conditions.

Intensity of reproduction is dependent on different preconditions for pistils and stamens and hence the total reproduction (formation of cones) can vary very much depending on the weather.

According the study, the formation of cones varies yearly and is particularly strong every three to four years.  Supposedly the same model applies to whole polar tree line of the Fennoscandia. There seem to be no difference between northern and southern parts of Scandinavia when it comes to frequency of good cone years though they not always occur in the same years.
  • Renvall, ORCID ID:E-mail:
article id 7527, category Article
August Renvall. (1913). Die periodischen Erscheinungen der Reproduktion der Kiefer an der polaren Waldgrenze. Acta Forestalia Fennica vol. 1 no. 2 article id 7527. https://doi.org/10.14214/aff.7527
English title: The periodic variation of the regeneration of pine (Pinus sylvestris) at the polar tree line.

The study deals with the preconditions for natural regeneration of the pine at the polar tree line in northern Finland and Sweden. The data has been collected in three summers from 1909 to 1911 in areas of Inari and Utsjoki in Finland and Kaaresuvanto, Jukkasjärvi und Pajala in Sweden. The yearly variation of seed production of pine is studied and compared with the age of the stand, site factors and weather conditions.

Intensity of reproduction is dependent on different preconditions for pistils and stamens and hence the total reproduction (formation of cones) can vary very much depending on the weather.

According the study, the formation of cones varies yearly and is particularly strong every three to four years.  Supposedly the same model applies to whole polar tree line of the Fennoscandia. There seem to be no difference between northern and southern parts of Scandinavia when it comes to frequency of good cone years though they not always occur in the same years.
  • Renvall, 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 7669, category Article
Leena Finér. (1991). Effect of fertilization on dry mass accumulation and nutrient cycling in Scots pine on an ombrotrophic bog. Acta Forestalia Fennica no. 223 article id 7669. https://doi.org/10.14214/aff.7669

The first three-year effects of PK(MgB) and NPK(MgB) fertilization on the dry mass accumulation and nutrient cycling were studied in a Scots pine (Pinus sylvestris L.) stand growing on a drained low-shrub pine bog in Eastern Finland. The total dry mass of the tree stand before fertilization was 78 tn/ha, of which the above-ground compartments accounted for 69%. The annual above-ground dry mass production was 6.3 tn/ha, 51% of it accumulating in the tree stand.

The study period was too short for detecting any fertilization response in the stems. The total dry mass accumulation was not affected, because the increase in foliar and cone dry masses after both fertilization treatments, and that of the living branches after NPK fertilization, were compensated by the decrease in the dry mass of dead branches.

The nutrients studied accounted for 392 kg/ha (0.49%) of the total dry mass of the tree stand before fertilization. The amounts were as follows; N 173 kg/ha (44%), Ca 90 kg (23%), K 58 kg/ha (15%). The rest (18%) consisted of P, Mg, S and micronutrients combined. The unfertilized trees took up the following amounts of nutrients of the soil: N 15.6, Ca 12.8, K 4.1, P 1.3, MG 1.7, and S and Mn 1.5 kg/ha. The uptake of Fe and Zn was 510 and 130 g/ha and that of B and Cu less than 100 g/ha. More than 50% of the nutrient uptake, except for that of K and Fe, was released in litterfall. The results indicated very efficient cycling of K, Mn and B between the soil and trees.

The fertilized stands accumulated more N, P, K and B than the unfertilized ones during the tree-year study period. The increased accumulation corresponded to 35% (52 kg/ha) of the N applied on the NPK fertilized plots, 10% of the P, 25% of the K and 10% of the B on the PK and NPK fertilized plots. The increased amount of B released in litterfall after fertilization was equivalent to 4% of the applied B. Fertilization inhibited the uptake of Mn and Ca.

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  • Finér, ORCID ID:E-mail:
article id 7667, category Article
Veli Pohjonen. (1991). Selection of species and clones for biomass willow forestry in Finland. Acta Forestalia Fennica no. 221 article id 7667. https://doi.org/10.14214/aff.7667

Willow (Salix sp.) species and clones have been selected in Finland, originally for basket willow husbandry, since 1910's. Screening for biomass willows started in 1973 by the Foundation for Forest Tree Breeding. Biomass willow research for energy started in 1978. The objective of the study was, based on theoretical background, on historical record of Finnish willow research between 1910–80 and on analysis of the Finnish biomass willow research of the 1980s, a further selection of exotic and indigenous willows for energy and chemicals.

Swedish selection of 63 exotics, mainly of Salix viminalis L. and S. burjatica Nazarov, was screened in Kompparnäs willow research site in the southern coast of Finland in 1983–89. S. viminalis showed both high yield potential and good crop certainty. The yield variation in S. burjatica were big due to rust (Melampsora sp.) infection followed by lowered winter hardiness. Three recommendable S. viminalis clones for Southern Finland were found.

Finnish indigenous species were screened based on collection (375 clones) in 1974–74 of the Foundation for Forest Tree Breeding, and the Finnish 4H-organization (566 clones) in 1978–79 in test sites in Suomusjärvi, Nurmijärvi, Kannus and Haapavesi. Salix myrsinifolia Salisb. was most productive of the indigenous willows. Five recommendable clones were selected. The second most productive indigenous was S. phylicifolia, with three recommendable clones. Based on willow hybridization studies in the Finnish Forest Research Institute, a considerable additional selection effect, boosted by heterosis, was found from the progenies. Further intraspecific crossings of geographically distant clones of S. myrsinifolia are recommended.

Based on the results, S. viminalis is recommended for practical biomass forestry application in the southernmost agroclimatic zone of Finland. S. myrsinifolia is recommended for further research and development in the other zones.

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  • Pohjonen, ORCID ID:E-mail:
article id 7651, category Article
Raymond K. Omwami. (1988). An economic model underlying the choice of capital intensity in timber production. Acta Forestalia Fennica no. 204 article id 7651. https://doi.org/10.14214/aff.7651

The process of capital accumulation in timber production has been examined in this study. A detailed explanation of new investment in forest industry in terms of productive capacity as the determinant of national forest policy target growing stock and silviculture is presented. The basis of the explanation of forest industry productive capacity was a linear vertically integrated input-output production model. The model was used to derive a macroeconomic equilibrium condition specifying forest sector aggregate demand as an integral part of the national economy. Timber production has been constructed as a state variable system and the Maximum Principle used to derive silvicultural investment criterion. The derivation of the investment criterion was formulated as a dynamic problem in a labour surplus economy with linkage between savings and choice of silvicultural technology defined via income distribution between wages and profit. Maximization of aggregate consumption was specified as the goal of timber production.

By assuming a state of sub-optimal savings rate, it is shown that the real cost of labour is not zero in a labour surplus economy. Because unemployment labour is not a free commodity, it is concluded that capital-intensive silvicultural technology represents an optimal means of maximizing aggregate consumption in labour surplus economy, contrary to the recommendation of social marginal productivity theory.

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  • Omwami, ORCID ID:E-mail:
article id 7616, category Article
Min-Sup Chung. (1981). Flowering characteristics of Pinus sylvestris L. with special emphasis on the reproductive adaptation to local temperature factor. Acta Forestalia Fennica no. 169 article id 7616. https://doi.org/10.14214/aff.7616

Flowering time and characteristics of cones and seed development of Scots pine (Pinus sylvestris L.) plus tree clones originating from various parts of Finland and planted (grafts) in Southern Finland (61° 48’ N, 29° 19’ E) were studied during 1976-1978.

The flowering time (in terms of period unit (p.u.) sums for flowering) of the Scots pine plus tree clones showed characteristics specific to each population and the characteristics appear mainly adapted to the local temperature factor within Finland. Generally, the development of floral organs, cones and seed in the spring and summer seasons also showed a temperature dependence in that the reproductive organs are developed rapidly and/or favourably under higher temperature conditions within its optimum range.

In this respect, establishment of northern Scots pine seed orchards in Central or Southern Finland or an optimum flowering, and a favourable seed development with an optimum physiological reproductive isolation from surrounding Scots pine populations can be justified. Problem arising from the north-south transfer of seed orchards and the significance of trees’ growth rhythm are discussed in connection with tree improvement.

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  • Chung, ORCID ID:E-mail:
article id 7585, category Article
Jorma Ahvenainen. (1976). Suomen paperiteollisuuden kilpailukyky 1920- ja 1930-luvulla. Acta Forestalia Fennica no. 151 article id 7585. https://doi.org/10.14214/aff.7585
English title: The competitive position of the Finnish paper industry in the inter-war years.

The aim of the present study was to explain how the Finnish paper industry increased its production and its exports, broadened its markets and managed to show a profit in its activities during the period between the two world wars, despite the restrictive international commercial policies then prevailing, and despite the economic depression of the thirties. Newsprint has been treated as a subject for detailed examination.

The study is based on a comparative investigation of the price received by the paper mills for their paper and the costs of production. Since the market price of paper fell during the twenty years in question, one must examine how the mills responded to the reduction in selling price. Technically the study ranges from the valuation of the standing timber to the handing over of the finished product to the buyer. Between 1929 and 1933 the cost of producing newsprint fell by 387 marks per ton.

The most significant factor in maintaining competitive power was the technical development and increased output brought about in the mills. That alone accounted for half the savings achieved. The reduction in the buying price of wood and in delivery costs accounted for about a third of the difference in production costs, and other factors for the remaining fifth. In addition, the devaluation of the Finnish mark was crucial. Measures taken to reduce costs were effective in so far as the paper mills, with only one or two exceptions, maintained their competitiveness in international markets and managed not only to retain but also to extend their markets.

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  • Ahvenainen, ORCID ID:E-mail:
article id 7578, category Article
Yrjö Ilvessalo, Mikko Ilvessalo. (1975). Suomen metsätyypit metsiköiden luontaisen kehitys- ja puuntuottokyvyn valossa. Acta Forestalia Fennica no. 144 article id 7578. https://doi.org/10.14214/aff.7578
English title: The forest types of Finland in the light of natural development and yield capacity of forest stands.

The aim of the present study was to describe the forest types of Finnish mineral forest lands as a uniform whole in the light of stand development and wood production.

The study shows that it has been possible to work out uniform age-based development series for different stand characteristics for forest types on mineral forest lands in Finland. There is generally a clear difference in the development series of various stand characteristics and their average values between different forest types. The exceptions in a few places have been explained as depending on certain factors. The differences between adjacent forest types in order of their quality are of varying magnitude, thus differing from a schematic site quality classification obtained through calculation. Consequently, each forest type has its own development series with regard to the stand characteristics.

The number of forest types in the whole country is rather high. However, the different forest types are limited to different parts cf the country in such a way that there is no need for more than 5–6 forest types and 4 northerly sub-forms (-types) in each region, except in the border areas between the regions. In Finland the forest types have been the basis of forest site classification in forest research and practical forestry over a period of half a century. In pointing out the necessity of further study of forest types, Cajander has stressed the examination of differences in the compositions of vegetation between different classes of density of tree-stand and building up average descriptions of vegetation in such classes in young, middle-age and old stands. The same may be caused by some other factors which also are of essential influence to the composition of the vegetation.

The PDF includes a summary in English.

  • Ilvessalo, ORCID ID:E-mail:
  • Ilvessalo, ORCID ID:E-mail:
article id 7577, category Article
Pekka Kilkki, Raimo Pökälä. (1975). A long-term timber production model and its application to a large forest area. Acta Forestalia Fennica no. 143 article id 7577. https://doi.org/10.14214/aff.7577

A long-term timber production model was developed. The model is based upon numerical simulation and it is viewed only as a means of providing the decision-maker with values of the predicting variables in his utility function. Special attention was paid to the development of automatic cutting decision rules. The model was applied to the area of 2,752,000 hectares of forest land in Central Finland. The measurement data were extracted from the Sixth National Forest Inventory, which was made in 1973. Utilities from a hypothetical utility function were attained to a number of feasible timber production policies. The Bayes and maximin criteria were employed to evaluate these policies.

The PDF includes a summary in Finnish.

  • Kilkki, ORCID ID:E-mail:
  • Pökälä, ORCID ID:E-mail:
article id 7577, category Article
Pekka Kilkki, Raimo Pökälä. (1975). A long-term timber production model and its application to a large forest area. Acta Forestalia Fennica no. 143 article id 7577. https://doi.org/10.14214/aff.7577

A long-term timber production model was developed. The model is based upon numerical simulation and it is viewed only as a means of providing the decision-maker with values of the predicting variables in his utility function. Special attention was paid to the development of automatic cutting decision rules. The model was applied to the area of 2,752,000 hectares of forest land in Central Finland. The measurement data were extracted from the Sixth National Forest Inventory, which was made in 1973. Utilities from a hypothetical utility function were attained to a number of feasible timber production policies. The Bayes and maximin criteria were employed to evaluate these policies.

The PDF includes a summary in Finnish.

  • Kilkki, ORCID ID:E-mail:
  • Pökälä, ORCID ID:E-mail:
article id 4638, category Article
Risto Sarvas. (1953). Ohjeita pluspuiden valitsemista ja ilmoittamista varten. Silva Fennica no. 80 article id 4638. https://doi.org/10.14214/sf.a14054
English title: Instruction for the selection and registration of plus trees.

Silva Fennica Issue 80 includes presentations held in 1952 in the 7th 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 principles of breeding of forest trees and the selection of fast growing, healthy and qualitatively good trees, named plus trees, for seed production in Finland.

  • Sarvas, ORCID ID:E-mail:
article id 4558, category Article
Olli Heikinheimo. (1939). Kokemuksia paksusammaltyypin metsien käsittelystä. Silva Fennica no. 52 article id 4558. https://doi.org/10.14214/sf.a13965
English title: Experiences in forest management of Hylocomnium-Myrtillus type forests in Northern Finland.

Silva Fennica issue 52 includes presentations held in professional development courses, arranged for foresters working in public administration in 1938. 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 a study of forest management practices suitable for in Hylocomnium-Myrtillus site type forests, typical for Northern Finland. A special problem for the forest site type is poor regeneration due weak seed production of Norway spruce (Picea abies L. Karst.) and thick moss layer.

  • Heikinheimo, ORCID ID:E-mail:
article id 4487, category Article
Erkki J. Kinnunen. (1937). Metsäseutujen työläisten omavaraistuttaminen elintarvikkeisiin nähden. Silva Fennica no. 39 article id 4487. https://doi.org/10.14214/sf.a13897
English title: Promoting self-sufficiency in food supply of the farms in the remote areas of Finland.

Silva Fennica Issue 39 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. The education was arranged by Forest Service.

This presentation studies the food supply and economic situation of the farmers in the remote parts of Finland.

  • Kinnunen, ORCID ID:E-mail:

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