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Articles containing the keyword 'climate'.

Category: Commentary

article id 461, category Commentary
Sari Palmroth. (2009). Boreal forest and climate change – from processes and transport to trees, ecosystems and atmosphere. Silva Fennica vol. 43 no. 4 article id 461. https://doi.org/10.14214/sf.461
Book review: Hari, P. & Kulmala, L. (eds.). 2008. Boreal Forest and Climate Change. Advances in Global Change Research 34. Springer. 582 p. ISBN 978-1-4020-8717-2.
  • Palmroth, Duke University, Nicholas School of the Environment, Box 90328 Duke University, Durham, USA ORCID ID:E-mail: sari.palmroth@duke.edu (email)

Category: Research article

article id 10040, category Research article
Bengt Andersson Gull, Torgny Persson, Aleksey Fedorkov, Tim J. Mullin. (2018). Longitudinal differences in Scots pine shoot elongation. Silva Fennica vol. 52 no. 5 article id 10040. https://doi.org/10.14214/sf.10040
Highlights: More northerly Scots pine origins exhibit earlier onset and cessation of shoot growth; Continental origins show more northern phenological behaviour; Heat accumulation requirements for onset are not fixed and may be lower when accumulating slower; Scots pine may suffer from spring frost due to earlier growth onset in a warming climate; Phenological traits show potential to adapt to new climate conditions by breeding.

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

  • Andersson Gull, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden ORCID ID: https://orcid.org/0000-0003-3556-3172 E-mail: bengt.anderssongull@skogforsk.se
  • Persson, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden ORCID ID:E-mail: torgny.persson@skogforsk.se
  • Fedorkov, The Institute of Biology of Komi Scientific Centre of the Ural Branch of the Russian Academy of Sciences (IB Komi SC UB RAS), Kommunisticheskaya St., 28, Syktyvkar, 167982, Russia ORCID ID: https://orcid.org/0000-0001-7800-7534 E-mail: fedorkov@ib.komisc.ru
  • Mullin, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden ORCID ID: https://orcid.org/0000-0003-4924-1836 E-mail: tim.mullin@skogforsk.se (email)
article id 9980, category Research article
Eino Levkoev, Lauri Mehtätalo, Katri Luostarinen, Pertti Pulkkinen, Anatoly Zhigunov, Heli Peltola. (2018). Development of height growth and frost hardiness for one-year-old Norway spruce seedlings in greenhouse conditions in response to elevated temperature and atmospheric CO2 concentration. Silva Fennica vol. 52 no. 3 article id 9980. https://doi.org/10.14214/sf.9980
Highlights: Elevated temperature resulted in increased height growth, delayed onset and shortened duration of autumn frost hardiness development in Norway spruce seedlings; Elevated temperature increased variation between genotypes in height growth and frost hardiness development; Elevated atmospheric CO2 concentration had no effect on the development of height or autumn frost hardiness in Norway spruce seedlings.

The mean temperature during the potential growing season (April–September) may increase by 1 °C by 2030, and by 4 °C, or even more, by 2100, accompanied by an increase in atmospheric CO2 concentrations of 536–807 ppm, compared to the current climate of 1981–2010, in which atmospheric CO2 is at about 350 ppm. This may affect both the growth and frost hardiness of boreal trees. In this work, we studied the responses of height and autumn frost hardiness development in 22 half-sib genotypes of one-year-old Norway spruce (Picea abies (L.) Karst.) seedlings to elevated temperatures and atmospheric CO2 concentration under greenhouse conditions. The three climate treatments used were: T+1 °C above ambient and ambient CO2; T+4 °C above ambient and ambient CO2; and T+4 °C above ambient and elevated CO2 (700 ppm). The height growth rate and final height were both higher under T+4 °C compared to T+1 °C. Temperature increase also delayed the onset, and shortened the duration, of autumn frost hardiness development. Elevated CO2 did not affect the development of height or frost hardiness, when compared to the results without CO2 elevation under the same temperature treatment. Higher temperatures resulted in greater variation in height and frost hardiness development among genotypes. Three genotypes with different genetic backgrounds showed superior height growth, regardless of climate treatment; however, none showed a superior development of autumn frost hardiness. In future studies, clonal or full-sib genetic material should be used to study the details of autumn frost hardiness development among different genotypes.

  • Levkoev, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: eino.levkoev@uef.fi (email)
  • Mehtätalo, University of Eastern Finland, Faculty of Science and Forestry, School of Computing, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: lauri.mehtatalo@uef.fi
  • Luostarinen, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: katri.luostarinen@uef.fi
  • Pulkkinen,  Natural Resources Institute Finland (Luke), Production systems, Haapastensyrjä Breeding Station, FI-16200 Läyliäinen, Finland ORCID ID:E-mail: pertti.pulkkinen@luke.fi
  • Zhigunov, Saint-Petersburg State Forest Technical University, Forestry Faculty, RU-194021, Institutskiy per. 5, Saint-Petersburg, Russia ORCID ID:E-mail: a.zhigunov@bk.ru
  • Peltola, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: heli.peltola@uef.fi
article id 7751, category Research article
Göran Nordlander, Euan G. Mason, Karin Hjelm, Henrik Nordenhem, Claes Hellqvist. (2017). Influence of climate and forest management on damage risk by the pine weevil Hylobius abietis in northern Sweden. Silva Fennica vol. 51 no. 5 article id 7751. https://doi.org/10.14214/sf.7751
Highlights: Analysis of survey data from 292 reforestation areas in northern Sweden show that the probability of pine weevil damage can be predicted with a standard error of 0.12; Three variables are important in the optimal model: proportion of seedlings in mineral soil, age of clear-cut, and temperature sum; Temperature sum in the model can be adjusted to reflect future climate scenarios.

The pine weevil Hylobius abietis L. is an economically important pest insect that kills high proportions of conifer seedlings in reforestation areas. It is present in conifer forests all over Europe but weevil abundance and risk for damage varies considerably between areas. This study aimed to obtain a useful model for predicting damage risks by analyzing survey data from 292 regular forest plantations in northern Sweden. A model of pine weevil attack was constructed using various site characteristics, including both climatic factors and factors related to forest management activities. The optimal model was rather imprecise but showed that the risk of pine weevil attack can be predicted approximatively with three principal variables: 1) the proportion of seedlings expected to be planted in mineral soil rather than soil covered with duff and debris, 2) age of clear-cut at the time of planting, and 3) calculated temperature sum at the location. The model was constructed using long-run average temperature sums for epoch 2010, and so effects of climate change can be inferred from the model by adjustment to future epochs. Increased damage risks with a warmer climate are strongly indicated by the model. Effects of a warmer climate on the geographical distribution and abundance of the pine weevil are also discussed. The new tool to better estimate the risk of damage should provide a basis for foresters in their choice of countermeasures against pine weevil damage in northern Europe.

  • Nordlander, Swedish University of Agricultural Sciences (SLU), Department of Ecology, P.O. Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: Goran.Nordlander@slu.se
  • Mason, University of Canterbury, School of Forestry, Private Bag 4800, Christchurch 8140, New Zealand; Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID: http://orcid.org/0000-0001-9024-9106 E-mail: euan.mason@canterbury.ac.nz (email)
  • Hjelm, Skogforsk, The Forest Research Institute of Sweden, Ekebo 2250, SE-268 90 Svalöv, Sweden; Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: karin.hjelm@skogforsk.se
  • Nordenhem, Swedish University of Agricultural Sciences (SLU), Department of Ecology, P.O. Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: h.nordenhem@telia.com
  • Hellqvist, Swedish University of Agricultural Sciences (SLU), Department of Ecology, P.O. Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: Claes.Hellqvist@slu.se
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 1391, category Research article
Roberts Matisons, Jānis Jansons, Juris Katrevičs, Āris Jansons. (2015). Relation of tree-ring width and earlywood vessel size of alien Quercus rubra L. with climatic factors in Latvia. Silva Fennica vol. 49 no. 4 article id 1391. https://doi.org/10.14214/sf.1391
Highlights: Climate-growth relationships of red oak from three sites in Latvia were studied; Tree-ring width was mainly affected by temperature and precipitation in late summer; Vessel size was correlated with temperature parameters in autumn–spring; Sets of climatic factors significant for growth of red oak differed between sites; Changes in climate-growth relationships occurred during 20th century.

The effect of climatic factors on wood anatomy of the alien red oak (Quercus rubra L.) growing in three experimental plantations in Latvia was assessed by classical dendrochronological techniques. Two tree-ring proxies – tree-ring width (TRW) and mean area of earlywood vessel lumen (VLA) – were studied on 33 trees. Annual variation of TRW amongst trees was similar (mean r = 0.46), but there was more individuality in VLA (mean r = 0.26); nevertheless, chronologies of both proxies had rather synchronous variation amongst the sites. Annual variation of TRW was affected by factors related to water deficit in late summer, as suggested by the negative effect of temperature and positive effect of precipitation that have intensified during the 20th century, likely due to warming. Although weather conditions during the dormant period did not directly affect TRW, temperature during the autumn-spring period has been the main climatic determinant of VLA likely via influence on overwintering and hence vigour of tree. This suggests that conductive properties of wood and hence the susceptibility to water deficit have been affected by weather conditions before the formation of tree rings. During the 20th century, sensitivity of VLA has shifted from temperature in winter to temperature in autumn likely due to climate change. Still, the positive effect of these factors suggests that warming of climate would increase VLA and hence the risk of embolism and xylem disfunction. Therefore, the importance of availability of water for growth of red oak in Latvia is increasing.

  • Matisons, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: robism@inbox.lv (email)
  • Jansons, Latvian Forest Competence Centre, Dzērbenes str. 27, Riga, Latvia, LV 1006 ORCID ID:E-mail: janis.jansons@silava.lv
  • Katrevičs, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: juris.katrevics@silava.lv
  • Jansons, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: aris.jansons@silava.lv
article id 1155, category Research article
Feng Chen, Yujiang Yuan, Wenshou Wei, Tongwen Zhang, Huaming Shang, Shulong Yu. (2015). Divergent response of tree-ring width and maximum latewood density of Abies faxoniana to warming trends at the timberline of the western Qinling Mountains and northeastern Tibetan Plateau, China. Silva Fennica vol. 49 no. 4 article id 1155. https://doi.org/10.14214/sf.1155
Highlights: We describe new tree-ring width and maximum latewood density chronologies of Faxon fir; Temperature is the most important limiting factor for the radial growth of Faxon fir; The tree-ring width series captured the warming trends and allowed detecting the recent warming in a long-term context, while the maximum latewood density series showed no upward trend.

Tree-ring width (TRW) and maximum latewood density (MXD) data of Faxon fir (Abies faxoniana Rehd. et Wils.) were analyzed for five timberline sites in the western Qinling Mountains and northeastern Tibetan Plateau, to investigate their relationships to climate change, especially twentieth century warming. The cross-correlations among TRW chronologies at the low-frequency band were higher, while the higher correlations among MXD chronologies were found at the high-frequency band. Response analysis showed that the tree-ring formation of fir trees was significantly and positively affected by temperature variations, while it was also negatively affected by precipitation. The TRW series captured the warming trends and allowed detecting the recent warming in a long-term context, while the MXD series showed no upward trend. We also found the temperature sensitivity of the TRW series is unstable over space and time. The divergent response between TRW and MXD might be caused by the seasonal variations of warming trends.

  • Chen, Key Laboratory of Tree-ring Physical and Chemical Research of China Meteorological Administration/Xinjiang Laboratory of Ecology, Institute of Desert Meteorology, China Meteorological Administration, 46 Jianguo Road, Urumqi 830002, China ORCID ID:E-mail: feng653@163.com (email)
  • Yuan, Key Laboratory of Tree-ring Physical and Chemical Research of China Meteorological Administration/Xinjiang Laboratory of Ecology, Institute of Desert Meteorology, China Meteorological Administration, 46 Jianguo Road, Urumqi 830002, China ORCID ID:E-mail: yuanyuj5502@sina.com
  • Wei, Key Laboratory of Tree-ring Physical and Chemical Research of China Meteorological Administration/Xinjiang Laboratory of Ecology, Institute of Desert Meteorology, China Meteorological Administration, 46 Jianguo Road, Urumqi 830002, China ORCID ID:E-mail: cycfqq@sohu.com
  • Zhang, Key Laboratory of Tree-ring Physical and Chemical Research of China Meteorological Administration/Xinjiang Laboratory of Ecology, Institute of Desert Meteorology, China Meteorological Administration, 46 Jianguo Road, Urumqi 830002, China ORCID ID:E-mail: tongwenzhang19820705@hotmail.com
  • Shang, Key Laboratory of Tree-ring Physical and Chemical Research of China Meteorological Administration/Xinjiang Laboratory of Ecology, Institute of Desert Meteorology, China Meteorological Administration, 46 Jianguo Road, Urumqi 830002, China ORCID ID:E-mail: shang8632@163.com
  • Yu, Key Laboratory of Tree-ring Physical and Chemical Research of China Meteorological Administration/Xinjiang Laboratory of Ecology, Institute of Desert Meteorology, China Meteorological Administration, 46 Jianguo Road, Urumqi 830002, China ORCID ID:E-mail: yushl@idm.cn
article id 1266, category Research article
Edwyn K. Midmore, Shelagh A. McCartan, Richard L. Jinks, Christine M. Cahalan. (2015). Using thermal time models to predict germination of five provenances of silver birch (Betula pendula Roth) in southern England. Silva Fennica vol. 49 no. 2 article id 1266. https://doi.org/10.14214/sf.1266
Highlights: Using cumulative germination data, thermal time models were developed for Betula pendula; Models indicated varying degrees of dormancy and pre-chill requirements among provenances; Thermal time parameters were used with climatic data to predict germination times under mild and cold winters in southern England; Predictions suggest that pre-chilled French seeds would germinate about six weeks later than the fastest germinating provenance.
Climate predictions indicate that growing conditions may become unfavourable for certain tree species in parts of Britain. Guidelines suggest some planting of seed sources from regions between 2° and 5° south of those currently used as part of a climate change adaptation strategy. However, there has been little research on the benefits and risks associated with the use of planting stock from more southerly seed sources. Seeds of five provenances of the ‘relatively’ dormant Betula pendula were germinated over a range of temperatures both with and without a pre-chill. Subsequently, a thermal time model was used to predict the impact of migrating these provenances to southern England. Results identified geographical differences in germination response; those from higher latitude were more sensitive to pre-chill.
  • Midmore, Forest Research Agency, Alice Holt, Surrey. Current: Dolwyddelan, Llandre, Ceredigion, Wales, SY24 5BZ ORCID ID:E-mail: emidmore@gmail.com
  • McCartan, Forest Research, Alice Holt, Farnham, Surrey, GU10 4LH, UK ORCID ID:E-mail: shelagh.mccartan@forestry.gsi.gov.uk (email)
  • Jinks, Forest Research, Alice Holt Lodge, Farnham, Surrey, GU10 4LH, UK ORCID ID:E-mail: richard.jinks@forestry.gsi.gov.uk
  • Cahalan, Bangor University, School of Environment, Natural Resources and Geography, Bangor, Gwynedd, Wales, LL57 2UW ORCID ID:E-mail: c.m.cahalan@bangor.ac.uk
article id 1220, category Research article
Elisabeth Düthorn, Lea Schneider, Oliver Konter, Philipp Schön, Mauri Timonen, Jan Esper. (2015). On the hidden significance of differing micro-sites on tree-ring based climate reconstructions. Silva Fennica vol. 49 no. 1 article id 1220. https://doi.org/10.14214/sf.1220
Highlights: Pines and spruces show growth level differences in wet and dry micro-sites with higher growth rates in the dry sites; Spruces show a robust climate-growth relationship with June-July temperatures; Application of collective detrending methods can bias long-term trends in climate reconstructions, if relict and recent samples originate from different micro-sites.
Tree-ring chronologies are commonly extended back in time by combining samples from living trees with relict material preserved in man-made structures or natural archives (e.g. lakes). Although spatially close, these natural archives and living-tree-sites often comprise different micro-climates. Inhomogeneous growth conditions among these habitats, which may yield offsets in growth-rates, require caution in data processing. Here we assess species-specific growth dynamics in two micro-habitats and their potential effects on long chronologies by combining tree-ring data from different living-tree-sites with an “artificial” subfossil dataset. Well replicated (n > 80) Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) chronologies from northern Fennoscandia, sampled directly at the lakeshore (wet) and several meters beyond the lakeshore (dry) reveal high coherence of the variance between micro-sites (rspruce = 0.59, rpine = 0.68). Significant differences of the Regional Curves (RC) indicate faster growth of both species at the drier site though. Growth differences are more pronounced between the spruce micro-sites. The combination of recent dry and wet spruce data with artificial relict data results in two long chronologies covering the last 800 years with substantially different trends, although they consist of the same relict material and the micro-site chronologies correlate significantly over the past two centuries. The combination of spruce samples from dry inland micro-sites with subfossil samples originating from the wet lake shore can result in an underestimation of past temperatures prior to the 19th century. Such effects, hidden in the composition of long chronologies (living trees + subfossil samples) can bias long-term trends in climate reconstructions.
  • Düthorn, Department of Geography, Johannes Gutenberg University, Becherweg 21, 55099 Mainz, Germany ORCID ID:E-mail: duethorn@uni-mainz.de (email)
  • Schneider, Department of Geography, Johannes Gutenberg University, Becherweg 21, 55099 Mainz, Germany ORCID ID:E-mail: l.schneider@geo.uni-mainz.de
  • Konter, Department of Geography, Johannes Gutenberg University, Becherweg 21, 55099 Mainz, Germany ORCID ID:E-mail: O.Konter@geo.uni-mainz.de
  • Schön, Department of Geography, Johannes Gutenberg University, Becherweg 21, 55099 Mainz, Germany ORCID ID:E-mail: philipp.schoen@gmx.de
  • Timonen, Natural Resources Institute Finland (Luke), Natural resources and bioproduction, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: mauri.timonen@metla.fi
  • Esper, Department of Geography, Johannes Gutenberg University, Becherweg 21, 55099 Mainz, Germany ORCID ID:E-mail: J.Esper@geo.uni-mainz.de
article id 1107, category Research article
Arvo Tullus, Arne Sellin, Priit Kupper, Reimo Lutter, Linnar Pärn, Anna K. Jasinska, Meeli Alber, Maarja Kukk, Tea Tullus, Hardi Tullus, Krista Lõhmus, Anu Sõber. (2014). Increasing air humidity – a climate trend predicted for northern latitudes – alters the chemical composition of stemwood in silver birch and hybrid aspen. Silva Fennica vol. 48 no. 4 article id 1107. https://doi.org/10.14214/sf.1107
Highlights: Hybrid aspen and silver birch trees grew more slowly under increased air humidity conditions and had higher concentrations of N and P and a lower K to N ratio in stemwood; Minor species-specific changes were detected in stemwood concentrations of cellulose and hemicellulose; Density, calorific value and concentrations of lignin and ash in stemwood were not affected by elevated humidity.
We studied the physicochemical properties of stemwood in saplings of silver birch (Betula pendula Roth) and hybrid aspen (Populus tremula L. × P. tremuloides Michx.), grown for four years under artificially elevated relative air humidity (on average by 7%) in field conditions, using the Free Air Humidity Manipulation (FAHM) research facility in Estonia. Altogether 91 sample trees from three experimental plots with manipulated air humidity and from three control plots were cut in the dormant season and sampled for the analysis of cellulose, hemicellulose, acid detergent lignin, macronutrients (N, P, K), ash content, density, and calorific value of wood. The analysed trees grew significantly more slowly under elevated humidity conditions, with a more pronounced effect on aspens. Significantly higher concentrations of N and P were observed in the stemwood of both aspens and birches grown under elevated humidity. This could be the result of a change in the content of living parenchyma cells and/or enhanced retranslocation of nutrients into wood parenchyma. Additionally, humidification resulted in a significantly higher concentration of cellulose and a lower concentration of hemicellulose in aspen stemwood, and in significantly lower concentrations of cellulose and K in birch stemwood. Elevated humidity did not affect lignin concentration, ash content, basic density and calorific value of stemwood. Results from the FAHM experiment suggest that the increasing air humidity accompanying global warming at northern latitudes will affect the growth and functioning of deciduous trees and forests, with obvious consequences also for forest management and industry.
  • Tullus, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: arvo.tullus@ut.ee (email)
  • Sellin, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: arne.sellin@ut.ee
  • Kupper, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: priit.kupper@ut.ee
  • Lutter, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: reimo.lutter@emu.ee
  • Pärn, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: linnar.parn@emu.ee
  • Jasinska, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia & Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland ORCID ID:E-mail: jasiak9@wp.pl
  • Alber, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: meeli.alber@ut.ee
  • Kukk, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: maarja.kukk@ut.ee
  • Tullus, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: tea.tullus@emu.ee
  • Tullus, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: hardi.tullus@emu.ee
  • Lõhmus, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: krista.lohmus@ut.ee
  • Sõber, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: anu.sober@ut.ee
article id 1120, category Research article
Ilari Lehtonen, Petri Hoppula, Pentti Pirinen, Hilppa Gregow. (2014). Modelling crown snow loads in Finland: a comparison of two methods. Silva Fennica vol. 48 no. 3 article id 1120. https://doi.org/10.14214/sf.1120
Highlights: A new method to model crown snow loads is presented and compared with a previously published simpler method; The heaviest crown snow loads in Finland are found to typically occur in the eastern parts of the country; The relative importance of different snow load types varies between different regions of Finland.
The spatial occurrence of heavy crown snow loads in Finland between 1961 and 2010 is studied by using for the first time a model that classifies the snow load into four different types: rime, dry snow, wet snow and frozen snow. In producing this climatology, we used meteorological observations made at 29 locations across Finland. The model performance is evaluated against classified daily images of canopy snow cover and with the help of two short case studies. The results are further compared to those achieved with a simpler method used in previous studies. The heaviest crown snow loads are found to occur typically in eastern Finland. The new method reveals that this holds not only for the total snow loads but also for the different snow load types, although there are certain differences in their geographical occurrence. The greatest benefit achieved with the new method is the inclusion of rime accretion. The forests most prone to heavy riming are those located on tree-covered hills in northern Finland, but as the terrain elevation affects riming efficiency greatly, these small-scale variations in the snow load amounts could not be described in this study in great detail. Moreover, the results are more inaccurate in northern Finland where variations in the terrain elevation are greater than elsewhere. Otherwise, the largest uncertainties in this study are related to wind speed measurements and possibly partly because of that, we were not able to detect any significant trends in the crown snow-load amounts over the study period.
  • Lehtonen, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail: ilari.lehtonen@fmi.fi (email)
  • Hoppula, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail: petri.hoppula@fmi.fi
  • Pirinen, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail: pentti.pirinen@fmi.fi
  • Gregow, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail: hilppa.gregow@fmi.fi
article id 63, category Research article
Leena Koivuranta, Tarja Latva-Karjanmaa, Pertti Pulkkinen. (2012). The effect of temperature on seed quality and quantity in crosses between European (Populus tremula) and hybrid aspens (P. tremula x P. tremuloides). Silva Fennica vol. 46 no. 1 article id 63. https://doi.org/10.14214/sf.63
Hybrid aspen (Populus tremula L. Populus tremuloides Michx.) plantations are expanding in Fennoscandia and the Baltic countries; however, the possible effects of plantations on the native European aspen (P. tremula) and the level of gene flow between European and hybrid aspen have not been investigated. We studied seed quantity and quality in intraspecific and interspecific crosses of the European and hybrid aspens over a two year period. In order to study whether elevated temperatures due to climate change would benefit the species differently, we performed the crosses in different temperatures. In both years, interspecific crosses produced more seeds with higher quality than intraspecific crosses. This result was most distinct in crosses between female hybrid aspen and male European aspen. In higher temperatures, relative germination difference between hybrid aspen seeds and seeds from P. tremula P. tremula crosses seems to increase. These results suggest that hybrid aspen may have a significant genetic impact on the European aspen, and this effect may be strengthened by climate warming.
  • Koivuranta, Finnish Forest Research Institute, Haapastensyrjä, Finland ORCID ID:E-mail:
  • Latva-Karjanmaa, Finnish Forest Research Institute, Haapastensyrjä, Finland ORCID ID:E-mail:
  • Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä, Finland ORCID ID:E-mail: pertti.pulkkinen@metla.fi (email)
article id 110, category Research article
Erlend Nybakk, Pablo Crespell, Eric Hansen. (2011). Climate for innovation and innovation strategy as drivers for success in the wood industry: moderation effects of firm size, industry sector, and country of operation. Silva Fennica vol. 45 no. 3 article id 110. https://doi.org/10.14214/sf.110
This study examines the relationships between firm financial performance and a) the climate for innovation and b) innovation strategy in the wood products industry. The focus is on the moderator effects of firm size, country of operation, and industry sector. Using a sample of 460 responses from chief executive officers and top managers of Norwegian and US firms, we conducted a regression analysis to probe for interaction effects. The sample included primary and secondary manufacturers of various sizes. Consistent with previous studies, we found a positive impact for both a climate for innovation and an innovation strategy on firm performance. In terms of moderation, only one interaction was found to be significant, representing a moderator effect of industry size on the climate-performance relationship. Further testing showed that secondary, large manufacturers exhibited a weaker, yet still positive, relationship between climate for innovation and performance. This low level of significant interactions suggests stability of the relationship among the main factors depicted in the model, with important implications for managers and future research. These findings indicate that a positive climate for innovation and a management committed to innovation through an innovation strategy have a positive effect on the bottom line of wood products firms. This effect holds true regardless of industry, size, or country, so most firms can benefit from the implementation of these pro-innovation practices.
  • Nybakk, Norwegian Forest and Landscape Institute, P.O. Box 115, N-1431 Ås, Norway ORCID ID:E-mail: nye@skogoglandskap.no (email)
  • Crespell, FPInnovations (Forintek Division), Vancouver, BC, Canada ORCID ID:E-mail:
  • Hansen, Oregon State University, College of Forestry, OR, USA ORCID ID:E-mail:
article id 41, category Research article
Ying Hou, Jintao Qu, Zukui Luo, Chao Zhang, Kaiyun Wang. (2011). Morphological mechanism of growth response in treeline species Minjiang fir to elevated CO2 and temperature. Silva Fennica vol. 45 no. 2 article id 41. https://doi.org/10.14214/sf.41
To test whether and how morphological traits are linked with growth responses of plants to temperature and CO2 is important for understanding the mechanism underlying how plant growth will respond to global warming. In this study, using closed-top chambers to mimic future elevated CO2 and temperature, the growth response, morphological traits of Minjiang fir (Abies faxoniana Rehd.et Wils.) and the relationship of the two were investigated after two years of exposure to the single and combined elevation of CO2 and temperature. The results showed that biomass of Minjiang fir was 21%, 31%, and 35% greater than the control in elevated CO2, elevated temperature and the combination of elevated CO2 and temperature treatments, respectively. Elevated CO2 and temperature significantly affected the morphology of Minjiang fir, and a few morphological traits were highly correlated with growth responses. Larger branch angles at the upper layer, crown volume, and relative crown length contributed to positive growth responses to elevated CO2, while decreased specific leaf area (SLA) constricted any further growth response. Leaf morphological traits were more closely correlated with the response ratio than crown did in the elevated temperature, while in the combination of elevated CO2 and temperature, crown was more correlated with the response ratio than the leaf morphological traits. Thus, our results indicate that morphological traits may contribute differently to growth responses under different experimental conditions.
  • Hou, Department of Life Sciences, Shangqiu Normal University, Shangqiu, China ORCID ID:E-mail:
  • Qu, Department of Life Sciences, Shangqiu Normal University, Shangqiu, China ORCID ID:E-mail:
  • Luo, School of Environment and Life Sciences, Kaili University, Kaili, China ORCID ID:E-mail:
  • Zhang, Shanghai Key Laboratory of Urbanization and Ecological Restoration, East China Normal University, Shanghai, China, and University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Wang, Shanghai Key Laboratory of Urbanization and Ecological Restoration, East China Normal University, Shanghai, China, and University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail: kywang@re.ecnu.edu.cn (email)
article id 30, category Research article
Hilppa Gregow, Heli Peltola, Mikko Laapas, Seppo Saku, Ari Venäläinen. (2011). Combined occurrence of wind, snow loading and soil frost with implications for risks to forestry in Finland under the current and changing climatic conditions. Silva Fennica vol. 45 no. 1 article id 30. https://doi.org/10.14214/sf.30
This work focuses on the combined occurrence of wind, snow loading and soil frost with implications for risks to forestry in Finland under the current and changing climatic conditions. For this purpose, we employ meteorological datasets, available for the period of 1971–2009 and global climate model (GCM) simulations for the current climate 1971–2000, and periods 2046–65 and 2081–2100 applying the A1B-climate change scenario. Based on our results, the wind and snow induced risks to Finnish forests are projected to increase in the future although the change in the occurrence of strong winds is small. This is because soil frost depths that support tree anchorage from late autumn to early spring in Finland are projected to nearly disappear in the southern and central parts of the country. Heavy snow loads > 30 kg m–2 are becoming more common in southern and eastern Finland despite that the average cumulative 5-day snow loads decrease in these areas by 18 to 50%, respectively. As a result of the changes in the combined occurrence of wind, snow loading and soil frost, the risk of climatic conditions making conifers liable to uprooting are projected to increase in southern, central and eastern Finland. In the north, the risk of stem breakage is becoming more pronounced under snow loading > 20 kg m–2. Despite some uncertainties related to this work, we assume that the findings can serve as valuable support for the risk assessment of wind and snow induced damages to Finnish forests and for forestry, in general.
  • Gregow, Finnish Meteorological Institute, Helsinki, Finland ORCID ID:E-mail: hilppa.gregow@fmi.fi (email)
  • Peltola, University of Eastern Finland, Faculty of Forest Sciences, Joensuu, Finland ORCID ID:E-mail: heli.peltola@uef.fi
  • Laapas, Finnish Meteorological Institute, Helsinki, Finland ORCID ID:E-mail:
  • Saku, Finnish Meteorological Institute, Helsinki, Finland ORCID ID:E-mail:
  • Venäläinen, Finnish Meteorological Institute, Helsinki, Finland ORCID ID:E-mail:
article id 453, category Research article
Eduard Schiessl, Michael Grabner, Gerald Golesch, Thomas Geburek, Silvio Schueler. (2010). Sub-montane Norway spruce as alternative seed source for a changing climate? A genetic and growth analysis at the fringe of its natural range in Austria. Silva Fennica vol. 44 no. 4 article id 453. https://doi.org/10.14214/sf.453
Insights into the intraspecific variation in climate response of forest trees and the utilization of suitable seed sources are required to maintain forest ecoystems under expected climate change. Individuals of Norway spruce with an anomalous spherical-shaped crown were characterized by genetic (using a mtDNA marker) and dendroclimatic analysis. Such trees occur frequently at the fringe of the spruce distribution in east/south-east Austria. We employed pair-wise comparisons between trees with spherical and “regular” conical crowns on 47 sites. No evidence was found for a different phylogeographic history of spherical and conical spruces, but the high allelic diversity at the nad1 locus highlighted the importance of east/south-east Austria as refugium and migration corridor for Norway spruce. Analysis of mean annual increment revealed a larger amount of earlywood within the sapwood area and fewer negative pointer years for spherical spruces than for conical ones, pointing at a higher vitality and smaller interactions between climate and growth for spherical spruces. Although the results cannot explain the anomalous crown form, they suggest spherical trees to have a higher ability to cope the warm and dry climate of the region than “regular” conical spruces. We discuss the origin of spherical crowns in terms of population history and phenotypic plasticity and speculate on possible effects of crown architecture on canopy-atmosphere exchange.
  • Schiessl, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail:
  • Grabner, Department of Material Sciences and Process Engineering, Institute of Wood Science and Technology, University of Natural Resources and Applied Life Sciences, Peter-Jordan-Strasse 82, A-1190 Vienna, Austria ORCID ID:E-mail:
  • Golesch, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail:
  • Geburek, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail:
  • Schueler, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail: silvio.schueler@bfw.gv.at (email)
article id 455, category Research article
Seppo Kellomäki, Matti Maajärvi, Harri Strandman, Antti Kilpeläinen, Heli Peltola. (2010). Model computations on the climate change effects on snow cover, soil moisture and soil frost in the boreal conditions over Finland. Silva Fennica vol. 44 no. 2 article id 455. https://doi.org/10.14214/sf.455
This study considered how climate change affects the accumulation of snow, the soil moisture and soil frost at sites without tree cover in boreal conditions in Finland (60°–70°N). An increase of 4.5 °C in annual mean temperature and 20 % in annual precipitation were assumed for Finland by the year 2100 according to A2 emission scenario. Along with climate, the soil type of the permanent inventory plots of the Finnish National Forest Inventory was used. Soil and climate data were combined by using a process-based ecosystem model. Calculations were done for four periods: current climate (1971–2000), near future (2001–2020), mid-term future (2021–2050) and long-term future (2071–2100). According to our simulations, the average monthly duration and depth of snow decreased over the simulation period. However, the increasing precipitation may locally increase the snow depths in the mid-term calculations. In the autumn and winter, the average volumetric soil moisture content slightly increased in southern Finland during the near future, but decreased towards the end of the century, but still remained on a higher level than presently. In northern Finland, the soil moisture in the autumn and winter increased by the end of this century. In the summertime soil moisture decreased slightly regardless of the region. Throughout Finland, the length and the depth of soil frost decreased by the end of the century. In the south, the reduction in the depth was largest in the autumn and spring, while in the mid-winter it remained relatively deep in the middle of the century. In the north, the depth tended to increase during the first two calculation periods, in some areas, even during the third calculation period (2071–2100) due to reduced insulation effects of snow during cold spells. The wintertime increase in soil moisture and reduced soil frost may be reflected to reduced carrying capacity of soil for timber harvesting.
  • Kellomäki, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail: seppo.kellomaki@uef.fi (email)
  • Maajärvi, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Strandman, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Kilpeläinen, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Peltola, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
article id 455, category Research article
Seppo Kellomäki, Matti Maajärvi, Harri Strandman, Antti Kilpeläinen, Heli Peltola. (2010). Model computations on the climate change effects on snow cover, soil moisture and soil frost in the boreal conditions over Finland. Silva Fennica vol. 44 no. 2 article id 455. https://doi.org/10.14214/sf.455
This study considered how climate change affects the accumulation of snow, the soil moisture and soil frost at sites without tree cover in boreal conditions in Finland (60°–70°N). An increase of 4.5 °C in annual mean temperature and 20 % in annual precipitation were assumed for Finland by the year 2100 according to A2 emission scenario. Along with climate, the soil type of the permanent inventory plots of the Finnish National Forest Inventory was used. Soil and climate data were combined by using a process-based ecosystem model. Calculations were done for four periods: current climate (1971–2000), near future (2001–2020), mid-term future (2021–2050) and long-term future (2071–2100). According to our simulations, the average monthly duration and depth of snow decreased over the simulation period. However, the increasing precipitation may locally increase the snow depths in the mid-term calculations. In the autumn and winter, the average volumetric soil moisture content slightly increased in southern Finland during the near future, but decreased towards the end of the century, but still remained on a higher level than presently. In northern Finland, the soil moisture in the autumn and winter increased by the end of this century. In the summertime soil moisture decreased slightly regardless of the region. Throughout Finland, the length and the depth of soil frost decreased by the end of the century. In the south, the reduction in the depth was largest in the autumn and spring, while in the mid-winter it remained relatively deep in the middle of the century. In the north, the depth tended to increase during the first two calculation periods, in some areas, even during the third calculation period (2071–2100) due to reduced insulation effects of snow during cold spells. The wintertime increase in soil moisture and reduced soil frost may be reflected to reduced carrying capacity of soil for timber harvesting.
  • Kellomäki, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail: seppo.kellomaki@uef.fi (email)
  • Maajärvi, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Strandman, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Kilpeläinen, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Peltola, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
article id 180, category Research article
Hongzhang Kang, Björn Berg, Chunjiang Liu, Carl J. Westman. (2009). Variation in mass-loss rate of foliar litter in relation to climate and litter quality in Eurasian forests: differences among functional groups of litter. Silva Fennica vol. 43 no. 4 article id 180. https://doi.org/10.14214/sf.180
With a data set of litter decomposition collected by means of literature survey, our objectives are 1) to determine the differences in the variation in the first-year mass loss (%) of leaf litter with regard to climate and litter quality among different functional groups of tree species in Eurasian forests, and 2) to determine the difference in effect of mean annual temperature (°C), annual precipitation (dm), as well as concentration of nitrogen (%), and lignin (%) on first-year mass loss over a wide range in climate and litter quality. The main results are as follows. 1) The significant differences between litter types in the relationships between first-year mass loss and climatic factors plus litter quality revealed clearly different decomposition patterns over the continent. Thus, differences were found between coniferous and broadleaf litter, between deciduous broadleaf and evergreen broadleaf as well as between genera and even within a genus, viz. between deciduous and evergreen Quercus. 2) With a change in a relative unit of climate and litter quality variables, there were clear differences in effects of mean annual temperature, annual precipitation, and nitrogen on first-year mass loss for different functional groups of trees. 3) We identified some broadleaf litter species that decomposed to 100% in one year and thus did not contribute to carbon sequestration in a humus layer. Thus, the variation in pattern of foliar litter decomposition with climate and litter quality across functional groups in Eurasian forests showed different decomposition strategies for litter of different groups and genera.
  • Kang, School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240, P. R. China ORCID ID:E-mail:
  • Berg, Department of Forest Ecology, University of Helsinki, Latokartanonkaari 7, FIN-00014 Finland; Dipartimento Biologia Strutturale e Funzionale. Complesso Universitario, Monte S. Angelo, Via Cinthia, IT-80126 Napoli, Italy ORCID ID:E-mail:
  • Liu, School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240, P. R. China; Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, P. R. China, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, P. R. China ORCID ID:E-mail: chjliu@sjtu.edu.cn (email)
  • Westman, Dipartimento Biologia Strutturale e Funzionale. Complesso Universitario, Monte S. Angelo, Via Cinthia, IT-80126 Napoli, Italy ORCID ID:E-mail:
article id 231, category Research article
Hilppa Gregow, Ulla Puranen, Ari Venäläinen, Heli Peltola, Seppo Kellomäki, David Schultz. (2008). Temporal and spatial occurrence of strong winds and large snow load amounts in Finland during 1961-2000. Silva Fennica vol. 42 no. 4 article id 231. https://doi.org/10.14214/sf.231
Information on the temporal and spatial occurrence of strong winds and snow loads on trees is important for the risk management of wind- and snow-induced damage. Meteorological measurements made at 19 locations across Finland during 1961–2000 are used to understand the temporal and spatial occurrence of strong winds and large snow loads. A Kriging interpolation method was used to produce a spatial analysis of wind-speed events above 11 m s–1, 14 m s–1, and greater or equal to 17 m s–1 and snowfall accumulation above 20 kg m–2 and 30 kg m–2. According to the analysis, wind speeds exceeded 14 m s–1 at least 155 times and reached 17 m s–1 only 5 times at inland locations during the 40 years. Large snowfall accumulations were more frequent in the higher-elevation inland areas than along the coast. The snow load on trees exceeded 20 kg m–2 about 65 times a year when averaged over all 40 years, but was as high as 150 times a year during the mild 1990s. The maximum number of heavy snow-load events occurred in 1994 in northern Finland, consistent with a forest inventory by the Finnish Forest Research Institute in 1992–1994. The findings of this study imply that the risk of wind-induced damage is highest in the late autumn when trees do not have the additional support of frozen soil. In contrast, the risk of snow-induced damage is highest at higher-elevations inland, especially in northern Finland.

* Erratum (23 Oct 2012): The authors have requested inclusion of an additional author. Author information should thus be as follows: Hilppa Gregow, Ulla Puranen, Ari Venäläinen, Heli Peltola, Seppo Kellomäki & David Schultz
  • Gregow, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail: hilppa.gregow@fmi.fi (email)
  • Puranen, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail:
  • Venäläinen, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail:
  • Peltola, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: heli.peltola@uef.fi
  • Kellomäki, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: seppo.kellomaki@uef.fi
  • Schultz, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail:
article id 243, category Research article
Rupert Seidl, Werner Rammer, Petra Lasch, Franz-Werner Badeck, Manfred J. Lexer. (2008). Does conversion of even-aged, secondary coniferous forests affect carbon sequestration? A simulation study under changing environmental conditions. Silva Fennica vol. 42 no. 3 article id 243. https://doi.org/10.14214/sf.243
To circumvent problems associated with even-aged, pure coniferous stands propagated outside their natural range alternative management strategies and conversion programs are currently discussed in Central Europe. However, a mainstreaming of such adapted silvicultural systems with climate change mitigation objectives is missing to date. In this study the objective was to assess in situ C storage under conditions of climate change in a secondary Norway spruce (Picea abies (L.) Karst.) forest management unit in Austria. Four management strategies (Norway spruce age class forestry, transition to continuous cover forestry with Norway spruce, conversion to mixed conifer/broadleaved stands, no management) were investigated under current climate and two transient climate change scenarios in a simulation study. By comparing the results of two independent forest ecosystem models (PICUS v1.41, 4C) applied under identical forcings and boundary conditions we aimed at addressing uncertainties in model-based projections. A transition to continuous cover forestry increased C storage in all climate scenarios (+45.4 tC·ha–1 to +74.0 tC·ha–1 over the 100 year analysis period) compared to the approximately balanced C budget under the age class system. For the mixed conifer/broadleaved management variant predictions of the two models diverged significantly (+29.4 tC·ha–1 and –10.6 tC·ha–1 in PICUS and 4C respectively, current climate). With regard to climate change impacts both models agreed on distinct effects on productivity but lower sensitivity of C stocks due to compensation from respiration and adaptive harvest levels. In conclusion, considering the potential effects of silvicultural decisions on C stocks climate change mitigation should be addressed explicitly in programs advocating targeted change in management paradigms.
  • Seidl, Institute of Silviculture, BOKU, Vienna, Austria ORCID ID:E-mail: rupert.seidl@boku.ac.at (email)
  • Rammer, Institute of Silviculture, BOKU, Vienna, Austria ORCID ID:E-mail:
  • Lasch, Potsdam Institute for Climate Impact Research e.V., Potsdam, Germany ORCID ID:E-mail:
  • Badeck, Potsdam Institute for Climate Impact Research e.V., Potsdam, Germany ORCID ID:E-mail:
  • Lexer, Institute of Silviculture, BOKU, Vienna, Austria ORCID ID:E-mail:
article id 259, category Research article
Jani Laturi, Jarmo Mikkola, Jussi Uusivuori. (2008). Carbon reservoirs in wood products-in-use in Finland: current sinks and scenarios until 2050. Silva Fennica vol. 42 no. 2 article id 259. https://doi.org/10.14214/sf.259
This study addresses the question of how much carbon will be sequestered in wood products during the coming decades in Finland. Using sawnwood and other wood material consumption data since the 1950s and inventory data of carbon reservoirs of wood products in the Finnish construction and civil engineering sector, we first derive estimates for the carbon reservoirs in wood products-in-use in that sector. We then extend the estimate to include all wood products-in-use. We find that the carbon pool of wood products in the Finnish construction and civil engineering sector grew by about 12% since an inventory for 2000, and that the overall estimate for carbon reservoirs of Finnish wood products in 2004 was 26.6 million tons of carbon. In building the scenarios until 2050, econometric time series models accounting for the relationship between wood material consumption and the development of GDP were used. The results indicate that the range of carbon reservoirs of wood products in Finland will be 39.6–64.2 million tons of carbon in the year 2050. The impacts of different forms of the decay function on the time-path of a carbon sink and its value in wood products were also studied. When a logistic decay pattern is used, the discounted value of the predicted carbon sink of wood products in Finland is between EUR850 and EUR1380 million – at the price level of EUR15/CO2 ton – as opposed to 440–900 million euros, if a geometric decay pattern is used.
  • Laturi, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: jani.laturi@metla.fi (email)
  • Mikkola, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Uusivuori, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 271, category Research article
Patrick Insinna, Risto Jalkanen, Bernhard Götz. (2007). Climate impact on 100-year foliage chronologies of Scots pine and Ponderosa pine in the northeast lowlands of Brandenburg, Germany. Silva Fennica vol. 41 no. 4 article id 271. https://doi.org/10.14214/sf.271
Due to differences in the high-frequency signal and mean sensitivity of needle parameters in Scots pine and Ponderosa pine revealed in previous investigations, variance caused by climate factors at a dry site in the northeast lowlands of Brandenburg was investigated. Although water is the general limiting factor for both tree species, there are evident differences in the climate-driven impact on individual needle parameters. Autumn precipitation of the previous year was equally important for Scots pine and Ponderosa pine, but summer precipitation was more significant for the needle parameters of Scots pine. In contrast to precipitation, temperature seems to have a minor impact on needle parameters. Although January temperatures are significant predictors for both species, intercorrelations between needle parameters and summer temperatures were found only for Ponderosa pine. Striking correlation was also found between sun activity and needle production in Ponderosa pine, but not Scots pine, indicating possible adaptation to solar radiation.
  • Insinna, Office for Environmental Protection Liechtenstein, Climate Change Division, P.O. Box 684, FL-9490 Vaduz, Liechtenstein ORCID ID:E-mail: patrick.insinna@aus.llv.li (email)
  • Jalkanen, Rovaniemi Research Unit, Finnish Forest Research Institute, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
  • Götz, Eberswalde University of Applied Sciences, Department of Forestry, Forest-Botanical Gardens, D-16225 Eberswalde, Germany ORCID ID:E-mail:
article id 338, category Research article
Andrea Vajda, Ari Venäläinen, Pekka Hänninen, Raimo Sutinen. (2006). Effect of vegetation on snow cover at the northern timberline: a case study in Finnish Lapland. Silva Fennica vol. 40 no. 2 article id 338. https://doi.org/10.14214/sf.338
The presence of permanent snow cover for 200–220 days of the year has a determining role in the energy, hydrological and ecological processes at the climate-driven spruce (Picea abies) timberline in Lapland. Disturbances, such as forest fires or forest harvesting change the vegetation pattern and influence the spatial variation of snow cover. This variability in altered snow conditions (in subarctic Fennoscandia) is still poorly understood. We studied the influence of vegetation on the small-scale spatial variation of snow cover and wind climate in the Tuntsa area that was disturbed by a widespread forest fire in 1960. Radar was applied to measure snow thickness over two vegetation types, the spruce-dominant fire refuge and post-fire treeless tundra. Wind modelling was used to estimate the spatial variation of wind speed and direction. Due to the altered surface roughness and the increased wind velocity, snow drifting was more vigorous on the open tundra, resulting in a 30-cm thinner snow cover and almost half the water equivalent compared to the forest values. The changes in local climate after the fire, particularly in snow cover, may have played an important role in the poor recovery of vegetation: a substantial area is still unforested 40 years after the fire.
  • Vajda, Finnish Meteorogical Institute, Climate and Global Change, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail: andrea.vajda@fmi.fi (email)
  • Venäläinen, Finnish Meteorogical Institute, Climate and Global Change, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail:
  • Hänninen, Geological Survey of Finland, P.O. Box 96, FI-02151 Espoo, Finland ORCID ID:E-mail:
  • Sutinen, Geological Survey of Finland, P.O. Box 77, FI-96101 Rovaniemi, Finland ORCID ID:E-mail:
article id 434, category Research article
Igor Drobyshev, Mats Niklasson, Per Angelstam. (2004). Contrasting tree-ring data with fire record in a pine-dominated landscape in the Komi Republic (Eastern European Russia): recovering a common climate signal. Silva Fennica vol. 38 no. 1 article id 434. https://doi.org/10.14214/sf.434
For the period 1420–1960 we contrasted fire events reconstructed at 14 sites distributed over a 50 km x 50 km area in the central part of the Komi Republic (European Russia) with a set of tree-ring width chronologies of Scots pine (Pinus sylvestris L.), developed for the same area. Our aim was to infer common climatic information contained in tree-ring variables and independently dated fire events with the help of a superposed epoch analysis. The strongest weather–growth link was shown for the latewood width, which was positively correlated with the temperature in April–May and July–August of the current growth season and with previous year precipitation in July–August. Earlywood width was positively affected by previous year precipitation in May and November. The relationship between yearly ring variables and multiple-site fire events was dependent on the seasonal timing of fire events as recorded in the scars. In years with early-season fires (which made up 37% of all fires dated with seasonal resolution) total ring width was significantly narrower. In years with late-season fires (63%) total ring width, earlywood, and latewood width were significantly wider. Years with late-season fires tended to be associated with local highs of the latewood width chronologies over 1400–1960, which implied a link between decadal-scale climate variation and fire regime of the area.
  • Drobyshev, SUFOR Project, Department of Plant Ecology and Systematics, Ecology Building, Sölvegatan 37, Lund University, SE-223 62 Lund, Sweden ORCID ID:E-mail: igor.drobyshev@ekol.lu.se (email)
  • Niklasson, SUFOR Project, Southern Swedish Forest Research Centre, SLU, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail:
  • Angelstam, Grimsö Wildlife Research Station, Department of Conservation Biology, Forest Faculty, SLU, SE-730 91 Riddarhyttan, Sweden ORCID ID:E-mail:
article id 499, category Research article
Mikhail V. Kozlov, Pekka Niemelä. (2003). Drought is more stressful for northern populations of Scots pine than low summer temperatures. Silva Fennica vol. 37 no. 2 article id 499. https://doi.org/10.14214/sf.499
Needle fluctuating asymmetry, which is a non-specific stress indicator, was used to evaluate responses of Scots pine (Pinus sylvestris L.) to annual climatic variation in the Kola Peninsula, NW Russia, during 1992–1999. Although the 30 trees surveyed for this study demonstrated individualistic responses to the temperature and precipitation of the growth seasons, at the population level we found no effect of temperature and a significant increase in fluctuating asymmetry with a decline in precipitation during the previous August. This finding suggests that the vitality of Scots pine populations at the northern tree limit is controlled by late summer precipitation rather than by temperatures of the growth season.
  • Kozlov, Section of Ecology, University of Turku, 20014 Turku, Finland ORCID ID:E-mail: mikoz@utu.fi (email)
  • Niemelä, Forestry Faculty, University of Joensuu, P.O. Box 111, 80101 Joensuu, Finland ORCID ID:E-mail:
article id 635, category Research article
Manfred J. Lexer, Karl Hönninger, Helfried Scheifinger, Christoph Matulla, Nikolaus Groll, Helga Kromp-Kolb. (2000). The sensitivity of central European mountain forests to scenarios of climatic change: methodological frame for a large-scale risk assessment. Silva Fennica vol. 34 no. 2 article id 635. https://doi.org/10.14214/sf.635
The methodological framework of a large-scale risk assessment for Austrian forests under scenarios of climatic change is presented. A recently developed 3D-patch model is initialized with ground-true soil and vegetation data from sample plots of the Austrian Forest Inventory (AFI). Temperature and precipitation data of the current climate are interpolated from a network of more than 600 weather stations to the sample plots of the AFI. Vegetation development is simulated under current climate (‘control run’) and under climate change scenarios starting from today's forest composition and structure. Similarity of species composition and accumulated biomass between these two runs at various points in time were used as assessment criteria. An additive preference function which is based on Saaty’s AHP is employed to synthesize these criteria to an overall index of the adaptation potential of current forests to a changing climate. The presented methodology is demonstrated for a small sample from the Austrian Forest Inventory. The forest model successfully simulated equilibrium species composition under current climatic conditions spatially explicit in a heterogenous landscape based on ground-true data. At none of the simulated sites an abrupt forest dieback did occur due to climate change impacts. However, substantial changes occured with regard to species composition of the potential natural vegetation (PNV).
  • Lexer, Institute of Silviculture, University of Agricultural Sciences, Peter-Jordanstrasse 70, A-1190 Vienna, Austria ORCID ID:E-mail: lexer@edv1.boku.ac.at (email)
  • Hönninger, Institute of Silviculture, University of Agricultural Sciences, Peter-Jordanstrasse 70, A-1190 Vienna, Austria ORCID ID:E-mail:
  • Scheifinger, Institute of Meteorology and Physics, University of Agricultural Sciences, Türkenschanzstrasse 18, A-1180 Vienna, Austria ORCID ID:E-mail:
  • Matulla, Institute of Meteorology and Physics, University of Agricultural Sciences, Türkenschanzstrasse 18, A-1180 Vienna, Austria ORCID ID:E-mail:
  • Groll, Institute of Meteorology and Physics, University of Agricultural Sciences, Türkenschanzstrasse 18, A-1180 Vienna, Austria ORCID ID:E-mail:
  • Kromp-Kolb, Institute of Meteorology and Physics, University of Agricultural Sciences, Türkenschanzstrasse 18, A-1180 Vienna, Austria ORCID ID:E-mail:
article id 634, category Research article
Marcus Lindner, Petra Lasch, Markus Erhard. (2000). Alternative forest management strategies under climatic change – prospects for gap model applications in risk analyses. Silva Fennica vol. 34 no. 2 article id 634. https://doi.org/10.14214/sf.634
The projected global climate change will influence growth and productivity of natural and managed forests. Since the characteristics of the future regional climate are still uncertain and the response of our forests to changes in the atmospheric and climatic conditions may be both positive or negative, decision making in managed forests should consider the new risks and uncertainties arising from climatic change, especially if the rotation periods are long. An extended version of the forest gap model FORSKA was applied to simulate the forest development at 488 forest inventory plots in the federal state of Brandenburg, Germany, under two climate and three management scenarios. The transient growth dynamics from 1990 to 2100 were investigated at four sites in different parts of the state, representing the variability of environmental and forest conditions within Brandenburg. The alternative management strategies led to distinct differences in forest composition after 110 years of simulation. The projected climate change affected both forest productivity and species composition. The impacts of alternative management scenarios are discussed. It is concluded that the extended forest gap model can be a valuable tool to support decision making in forest management under global change.
  • Lindner, Potsdam Institute for Climate Impact Research, P.O. Box 60 12 03, D-14412 Potsdam, Germany ORCID ID:E-mail: lindner@pik-potsdam.de (email)
  • Lasch, Potsdam Institute for Climate Impact Research, P.O. Box 60 12 03, D-14412 Potsdam, Germany ORCID ID:E-mail:
  • Erhard, Potsdam Institute for Climate Impact Research, P.O. Box 60 12 03, D-14412 Potsdam, Germany ORCID ID:E-mail:
article id 676, category Research article
Erik Sundström. (1998). Afforestation of low-productive peatlands in Sweden – a tree species comparison. Silva Fennica vol. 32 no. 4 article id 676. https://doi.org/10.14214/sf.676
In 1970, five low-productive treeless peatlands in Sweden, ranging from latitudes 56°N to 67°N, were drained and fertilized for afforestation. The aim of the study was to determine the effect of four ditch spacings, varying from 7.5 to 60 m, and five NPK-fertilizer combinations, on the survival and growth of planted Scots pine (Pinus sylvestris), lodgepole pine (Pinus contorta), Norway spruce (Picea abies), and silver birch (Betula pendula) seedlings. The assessments were carried out 18–22 years after planting. Neither silver birch, nor Norway spruce was regarded suitable for the site type. The mortality of silver birch was almost complete, and Norway spruce did not grow well in any of the study areas, however, better than Scots pine in the north. Lodgepole pine had better height and diameter growth but also higher mortality rates than Scots pine. In the two northernmost experimental areas no response to fertilization was found. In the other three areas, the response to fertilization did not differ between species. Phosphorus was the most effective of the added fertilizer elements, whereas nitrogen showed no positive effect. Broadcast fertilizer application, with three times higher amount of fertilizer per ha gave the same growth response as spot application.
  • Sundström, Swedish University of Agricultural Sciences, Dept. of Silviculture, S-901 83 Umeå, Sweden ORCID ID:E-mail: erik.sundstrom@ssko.slu.se (email)
article id 691, category Research article
Jacek Oleksyn, Mark G. Tjoelker, Peter B. Reich. (1998). Adaptation to changing environment in Scots pine populations across a latitudinal gradient. Silva Fennica vol. 32 no. 2 article id 691. https://doi.org/10.14214/sf.691
In several growth chamber and field experiments we examined the growth response of Scots pine (Pinus sylvestris L.) populations from a wide latitudinal range to temperature and photoperiod. The duration of the shoot elongation period of one-year-old seedlings was affected by temperature and photoperiod. In contrasting temperatures, 23/20 °C, 20/17 °C, and 17/14 °C (day/night), shoot elongation period for all populations was shortest in the high and longest in the low temperature treatments. The northern populations from 61–57°N ceased height growth earlier than the other populations in the southern 50°N photoperiod. The order of growth cessation among populations at 50°N in the chamber experiment and at 52°N in the field experiment was similar and related to observed population differences in terminal leader growth and total tree height. Since the length of growing season is under strong environmentally-mediated genetic control in Scots pine, potential climatic changes such as increasing temperature will probably alter the length and timing of growth in aboveground tree parts, but likely in the opposite direction (a shorter growing season) than has been often hypothesized (a longer growing season). Tree-ring analyses of a provenance experiment established in 1912 indicate that the main climatic factors that limited ring-width growth in Scots pine were air temperatures in the winter months of December through March. Low winter temperatures were followed by the formation of narrow rings over the next summer. Based on responses to temperature, Scots pine populations from the continuous European range can be divided in several geographic groups along a latitudinal gradient. Our results suggest that in developing new models to predict the response of Scots pine to changing environmental conditions, it is necessary to include intraspecific differentiation in acclimation and adaptation to environmental factors.
  • Oleksyn, Polish Academy of Sciences, Institute of Dendrology, Parkowa 5, PL-62-035 Kórnik, Poland; University of Minnesota, Department of Forest Resources, 1530 Cleveland Ave. N., St. Paul, MN 55108, USA ORCID ID:E-mail: oleks001@gold.tc.umn.edu (email)
  • Tjoelker, University of Minnesota, Department of Forest Resources, 1530 Cleveland Ave. N., St. Paul, MN 55108, USA ORCID ID:E-mail:
  • Reich, University of Minnesota, Department of Forest Resources, 1530 Cleveland Ave. N., St. Paul, MN 55108, USA ORCID ID:E-mail:

Category: Review article

article id 1650, category Review article
Uriel Safriel. (2017). Land Degradation Neutrality (LDN) in drylands and beyond – where has it come from and where does it go. Silva Fennica vol. 51 no. 1B article id 1650. https://doi.org/10.14214/sf.1650
Highlights: LDN, a mechanism for offsetting new losses of land’s productivity by restoring productivity of already degraded lands, would maintain the balance of productive lands; As target of Sustainable Development Goal LDN highlights the significance of land whose biological productivity is critical to human survival; Commissioning UNCCD to oversee the implementation of LDN empowers the UNCCD and its impact on sustainability.

The paper first reviews the desertification/land degradation syndrome, the shortcomings of attempts to control it and the consequences of this failure, including to climate change and biodiversity. It then examines the experience gained by carbon and biodiversity offsets that helped adapting the offsetting principle to the context of land degradation, by emphasizing the restoration of the many already degraded lands on earth, as major component of the Land Degradation Neutrality (LDN) mechanism. LDN is a new voluntary and aspirational target of a Sustainable Development Goal (SDG) under the UN 2030 Agenda for Sustainable Development, aimed at neutralizing the rate of lands coming under degrading use of their productivity. This by balancing the ongoing added degradation with similar rate of restoring equivalent lands whose productivity had been already degraded. If extensively implemented, LDN would stabilize the global amount of productive land by 2030. This would increase global food security and reduce poverty of land users, thus contributing to global sustainability. This review maintains that the failure of United Nations Convention to Combat Desertification (UNCCD) to reduce desertification triggered the emergence of LDN as a mechanism for addressing land degradation globally, rather than just desertification in the drylands. LDN accepted as target of a Sustainable Development Goal also legitimized UNCCD to lead and oversee the aspired process of achieving land degradation neutral world. This paper reviews the development of the LDN concept expressed in scientific deliberations and political advocacy, throughout the five years from inception in 2011 at the UNCCD Secretariat, to early 2016. It notes the fast and increasing acceptance of LDN, expressed in the initiation of implementation already in April 2015 by an increasing number of countries, and in the growing interest and engagement of scientists and policy-makers. But the paper also express concern regarding potential misuse of the concept.

  • Safriel, Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel ORCID ID:E-mail: uriel36@gmail.com (email)
article id 695, category Review article
Marja-Leena Päätalo. (1998). Factors influencing occurrence and impacts of fires in northern European forests. Silva Fennica vol. 32 no. 2 article id 695. https://doi.org/10.14214/sf.695
The return interval and number of fires vary, depending on the geographical location in interaction with climate, topography and amount of fuel. During recent decades, in northern Europe the number and severity of fires have been insignificant compared with Mediterranean region, in which fire return intervals may be 15–35 years, compared to the average of 60–120 years for boreal forests. This is partly due to the efficient system of fire protection in northern Europe, but is mainly due to the less favourable climate for fire and the smaller human impact on ignition of forest fires. The consequences of fire are related to both site and stand characteristics, site being the most important factor controlling the stability of stands. Dry sites being more flammable and likely to ignite are associated with high risk of fire. In northern Europe, due to the interaction between species and site, the role of species difference in risk of fire damage is not clear. In southern Europe, fire risk cannot be explained by differences between tree species. There, other vegetation (shrubs, etc.) is of major importance for the risk of fire. Management of forests can, to some degree, alter the risk and the occurrence of fire. In northern Europe, logging may have compensated for fire occurrence by decreasing the amount of fuel. In addition, forest roads act as fire-breaks and facilitate fire-fighting. On the contrary, in southern Europe the risk of fire has been found to increase because the traditional forest uses and management have decreased, which increases the accumulation of fuel. However, it is not yet possible to quantify and compare the effect of management in absolute terms. Currently, some tools, such as fire-risk indices, remote sensing and GIS-based techniques, are available for prediction of fire risk in some areas. For example, fire-risk indices are most suitable for areas, like northern Europe, which have a low fire risk. In high-risk areas, such as southern Europe, more sophisticated techniques are needed for assessment of the risk. In the future, assuming global warming at northern latitudes (2 x CO2 climate), the risk of fire damage could also increase in northern Europe. Therefore, to allow the various locational and silvicultural factors to be assessed on the European level, an integrated risk model is needed.
  • Päätalo, Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:

Category: Research note

article id 960, category Research note
Shou-Qin Sun, Liang Peng, Gen-Xu Wang, Yan-Hong Wu, Jun Zhou, Hai-Jian Bing, Dong Yu, Ji Luo. (2013). An improved open-top chamber warming system for global change research. Silva Fennica vol. 47 no. 2 article id 960. https://doi.org/10.14214/sf.960
This study is an assessment of an improved temperature warming system developed to enhance global warming research-based forest ecosystem and soil ecophysiological experiments. The architecture couples a standard open-top chamber (OTC) with a heating cable. A 16 m wire cable with an 18 W m-1 and 288 W h-1 power rating was coiled around a polyvinyl chloride (PVC) pipe 2.5 m in length and 3.5 cm in diameter. The pipe was reshaped into a circle and fixed inside the OTC at a height of 15 cm. PVC pipe distance to plants was 10 to 15 cm while distance to OTC inner walls was 15 cm. The cable was constructed from a heating source with an alloy resistance wire, an aluminum foil and copper wire shielded layer, a crosslinking polyethylene inner insulator, a PVC coating, and a tinned copper grounding wire. After the cable is powered up, air and soil inside the OTC-cable system is heated by conductivity. Temperature is manipulated according to the voltage and resistance of the cable. The OTC-cable system was developed to examine plant reaction to an increase in air and soil temperatures by 2.84 °C and 1.83 °C, respectively. Temperature values are adjustable by changing cable and PVC pipe length. It offers a new, affordable, low energy consumption and low running cost method by which to study climate change effects on forest ecosystems. This method is especially useful for application in forest ecosystems of many developing countries or in many remote areas of developed countries where the feasibility in supplying sufficient power from local power grids is questionable.
  • Sun, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, No. 9, Block 4, South Renmin Road, Chengdu, China, 610041 ORCID ID:E-mail: shouqinsun@imde.ac.cn (email)
  • Peng, Horticulture and Landscape College, Hunan Agricultural University, Furong District, Changsha, China, 410128 ORCID ID:E-mail: keith215@126.com
  • Wang, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China ORCID ID:E-mail: cookiedot@sina.cn
  • Wu, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China ORCID ID:E-mail: free2001@tom.com
  • Zhou, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China ORCID ID:E-mail: haitaosun@sohu.com
  • Bing, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China ORCID ID:E-mail: 78186181@qq.com
  • Yu, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China ORCID ID:E-mail: dongdyu@sohu.com
  • Luo, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China ORCID ID:E-mail: 1254157095@qq.com

Category: Article

article id 7479, category Article
Matti Franssila. (1958). Kulovaaran ja säätekijöiden välisestä riippuvuudesta. Acta Forestalia Fennica vol. 67 no. 5 article id 7479. https://doi.org/10.14214/aff.7479
English title: The dependence of forest fire danger on meteorological factors.
Original keywords: metsäpalot; ilmasto; kuivuus; maan kuivuus

The investigation is divided into statistical and experimental sections, the latter of which were conducted in a Vaccinium type Scots pine (Pinus sylvestris L.) stand with the aim of elucidating the interdependence of soil humidity and meteorological factors. The moisture content of pine needles and moss and wooden cylinders placed on the soil or slightly over the ground was determined by weighing. The results showed that there is correlation between the moisture content of the wooden cylinders and the relative humidity of air during the days without rain. Correlation between moisture content of pine needles and moss with the air was slightly poorer.

In the statistical section, based on meteorological observations made in the geophysical observatory at Sodankylä in Northern Finland in 1920-1943, and forest fire statistics of the area, forest fire days and days without forest fires were divided into 40 temperature-humidity groups. Of the 391 forest fires observed in the area, the cause of the fire was known in 353 cases, and 69% of these were caused by lightning. A forest fire danger index was calculated using the data. A sharp increase in the burned area when the index exceeded the limit k=0.3 seem to be explained by thunderstorms, which are the most notable cause of forest fires in the Sodankylä area.

The forest fire index was calculated also at four meteorological stations in different parts of the country using weather observations in 1927-1936. It appears that the number of days in which the k>0.1 decreases when proceeding northwards, obviously because of the shortening of the summer. On the other hand, the number of days in which k>0.3 increases towards the north.

The PDF includes a summary in English.

  • Franssila, ORCID ID:E-mail:
article id 7450, category Article
J. Keränen. (1954). Lämmityskausi ja sen lämpötekijät Suomen ilmastossa. Acta Forestalia Fennica vol. 62 no. 1 article id 7450. https://doi.org/10.14214/aff.7450
English title: Heating season and factors affecting temperature in Finnish climate.
Original keywords: lämmitys; ilmasto; Suomi; lämpötilat

The aim of the investigation was to estimate the effect of climate on the temperature observations and heating of buildings. Temperature data of observation stations in Finland and in the neighbouring countries near Finnish borders, in all 190 stations, was collected during heating season. 

Heating season begins in the northern border of Finland in 20th of July,  in Rovaniemi oin the Northern Finland in the middle of August, and 5th of September in the Southern coast of the country. Similarly, the heating season ends in 2.-10.6. in Southern and Central Finland, in June in Northern Finland, and in the middle of June in the Northernmost Finland, where heating season continued almost the whole year. In Southern Finland the length of heating season was 280 days. In the coldest heating season in 1942-1942 the heating decree-days increased most in the province of Varsinais-Suomi in Southern Finland. The increase decreased towards North. In the warmest heating season in 1929-1930 decrease of heating decree-days was similar in almost the whole country. The data can be used to define how different weather conditions affect the need of fuel.  

The PDF includes a summary in German. 

  • Keränen, ORCID ID:E-mail:
article id 7303, category Article
J. Keränen. (1934). Lämpöoloista puiden ja eräiden pensaiden kasvupaikkojen pohjoisilla rajoilla Suomessa. Acta Forestalia Fennica vol. 40 no. 26 article id 7303. https://doi.org/10.14214/aff.7303
English title: Thermal conditions in the northern limits of some tree species and bushes in Finland.

The article discusses the thermal conditions in the northern limits of trees and some bushes in Finland. Temperature is the most important limiting factor for distribution of plant species. Precipitation variations, however, are small in Finland. The article lists the main features of thermal conditions during the different seasons in different parts of Finland. The northern limits and the thermal condition of the area are described for the following species: Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.), mezereon, buckthorn, common alder, linden, elm, maple, hazel, ash, oak, hybrid mountain ash, yew and Swedish whitebeam.

The PDF includes a summary in English.

  • Keränen, ORCID ID:E-mail:
article id 7275, category Article
Esa Hyyppä. (1933). Das Klima und die Wälder der spätglazialen Zeit im Bereich der karelischen Landenge. Acta Forestalia Fennica vol. 39 no. 4 article id 7275. https://doi.org/10.14214/aff.7275
English title: The climate and forests in the late glacial time in the region of the Karelian Isthmus.

The study is based on pollen analyses of varves collected from Kivennapa area. The varves contain the plant fossils of Dryas sp., which were the typical plants of the era. Geological samples form the Russia side of the border are also utilized. The study describes the results regarding the late-glacial forests and the vegetation that consist mostly of Dryas sp. and the climate in the area in the late-glacial era.

The late-glacial era in the Karelian Isthmus should be divided into two periods and better named as glacial and subglacial eras, also known as arctic and subarctic eras. 

The PDF contains a summary in Finnish.

  • Hyyppä, ORCID ID:E-mail:
article id 7257, category Article
P. S. Tikka. (1929). Ulkomaisten puulajien kasvu- ja menestymissuhteista eräässä Kulosaaren yksityispuistikossa. Acta Forestalia Fennica vol. 35 no. 2 article id 7257. https://doi.org/10.14214/aff.7257
English title: Growth and success of exotic tree species in a private garden in Kulosaari, Finland.
English keywords: climate; provenance

The growth of 35 exotic tree species in garden established in 1912 is discussed in the article. The site is located in Kulosaari, Helsinki in the Southern coast of Finland. The species represented the Chamaecyparis, Abies, Tsuga, Picea, Larix, Pinus, Betula, Fagus, Quercus, Juglans, Populus, Salix, Tilia, Acer, Prunus, Crataegus and Amelanchier families. All the tree species from northern continental climate and most of the species of temperate regions grew well or moderately well. Species form northern oceanic climate succeeded moderately well. The species from southern continental or oceanic climate did not endure the climate in Kulosaari. Definite conclusions were not possible to make, because the precise origin of the seedlings was not known, and there was usually only one tree from each species.

The PDF includes a summary in German.

  • Tikka, ORCID ID:E-mail:
article id 5606, category Article
Pekka E. Kauppi, Pekka Hänninen, Helena M Henttonen, Antti Ihalainen, Eino Lappalainen, Maximilian Posch, Michael Starr, Pekka Tamminen. (1997). Carbon reservoirs in peatlands and forests in the boreal regions of Finland. Silva Fennica vol. 31 no. 1 article id 5606. https://doi.org/10.14214/sf.a8507

The carbon reservoir of ecosystems was estimated based on field measurements for forests and peatlands on an area in Finland covering 263,000 km2 and extending about 900 km across the boreal zone from south to north. More than two thirds of the reservoir was in peat, and less than ten per cent in trees. Forest ecosystems growing on mineral soils covering 144,000 km2 contained 10–11 kg C m-2 on an average, including both vegetation (3.4 kg C m-2) and soil (uppermost 75 cm; 7.2 kg C m-2). Mire ecosystems covering 65,000 km2 contained an average of 72 kg C m-2 as peat. For the landscape consisting of peatlands, closed and open forests, and inland water, excluding arable and built-up land, a reservoir of 24.6 kg C m-2 was observed. This includes the peat, forest soil and tree biomass. This is an underestimate of the true total reservoir, because there are additional unknown reservoirs in deep soil, lake sediments, woody debris, and ground vegetation. Geographic distributions of the reservoirs were described, analysed and discussed. The highest reservoir, 35–40 kg C m-2, was observed in sub-regions in central western and north western Finland. Many estimates given for the boreal carbon reservoirs have been higher than those of ours. Either the Finnish environment contains less carbon per unit area than the rest of the boreal zone, or the global boreal reservoir has earlier been overestimated. In order to reduce uncertainties of the global estimates, statistically representative measurements are needed especially on Russian and Canadian peatlands.

  • Kauppi, ORCID ID:E-mail:
  • Hänninen, ORCID ID:E-mail:
  • Henttonen, ORCID ID:E-mail:
  • Ihalainen, ORCID ID:E-mail:
  • Lappalainen, ORCID ID:E-mail:
  • Posch, ORCID ID:E-mail:
  • Starr, ORCID ID:E-mail:
  • Tamminen, ORCID ID:E-mail:
article id 5604, category Article
Nigel Dudley, Jean-Paul Jeanrenaud, Adam Markham. (1996). Conservation in boreal forests under conditions of climate change. Silva Fennica vol. 30 no. 2–3 article id 5604. https://doi.org/10.14214/sf.a9249

Addressing the potential impact of climate change on boreal forest ecosystems will require a range of new conservation techniques. During the early 1990s, the scope of WWF's (the World Wide Fund for Nature) forest policy work has broadened from a focus on tropical moist forests to a more general consideration of all the world's forests. Climate change is only one of a series of threats currently facing boreal forests.

Planning conservation strategies that take account of global warming is not easy when there are many computer models of climate change, sometimes predicting very different ecological effects. Climate change could result in some particularly extreme problems for the boreal forest biome. A summary of the problems and opportunities in boreal forests is presented. WWF has also been drawing up strategies for conservation on a global, regional and national level. The organization has concluded that conservation strategies aimed at combatting climate change need not be in direct conflict with other conservation planning requirements. However, proposals have emerged for ways to address the impacts of climate change that would have detrimental impacts on existing conservation plans.

  • Dudley, ORCID ID:E-mail:
  • Jeanrenaud, ORCID ID:E-mail:
  • Markham, ORCID ID:E-mail:
article id 5604, category Article
Nigel Dudley, Jean-Paul Jeanrenaud, Adam Markham. (1996). Conservation in boreal forests under conditions of climate change. Silva Fennica vol. 30 no. 2–3 article id 5604. https://doi.org/10.14214/sf.a9249

Addressing the potential impact of climate change on boreal forest ecosystems will require a range of new conservation techniques. During the early 1990s, the scope of WWF's (the World Wide Fund for Nature) forest policy work has broadened from a focus on tropical moist forests to a more general consideration of all the world's forests. Climate change is only one of a series of threats currently facing boreal forests.

Planning conservation strategies that take account of global warming is not easy when there are many computer models of climate change, sometimes predicting very different ecological effects. Climate change could result in some particularly extreme problems for the boreal forest biome. A summary of the problems and opportunities in boreal forests is presented. WWF has also been drawing up strategies for conservation on a global, regional and national level. The organization has concluded that conservation strategies aimed at combatting climate change need not be in direct conflict with other conservation planning requirements. However, proposals have emerged for ways to address the impacts of climate change that would have detrimental impacts on existing conservation plans.

  • Dudley, ORCID ID:E-mail:
  • Jeanrenaud, ORCID ID:E-mail:
  • Markham, ORCID ID:E-mail:
article id 5596, category Article
Renaat S.A.R. van Rompaey. (1996). Need for integrated policy oriented national research programmes: the second phase (1995–2001) of the Dutch National Research Programme on Global Air Pollution and Climate Change NRP. Silva Fennica vol. 30 no. 2–3 article id 5596. https://doi.org/10.14214/sf.a9241

As a follow-up on acid rain programmes many countries, e.g. Finland, the Netherlands, Sweden, launched national research programmes on Climate Change by the end of the eighties. Other countries centred new programmes on Global Change, such as Belgium, United Kingdom, Germany, Canada. Also, the European Community included the climate issue in the research programme 'Environment & Climate'. The conclusion of the Intergovernmental Panel on Climate Change (IPCC) shifted in the successive assessment reports from possible climate change to actual climate change. The paper describes the first and second phase of the Dutch Climate Change Research Programme, and discusses the future of the programme.

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

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

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

  • Fleming, ORCID ID:E-mail:
article id 5593, category Article
Malle Mandre, Jaan Klõseiko, Vaike Reisner, Hardi Tullus. (1996). Assessment of CO2 fluxes and effects of possible climate changes on forests in Estonia. Silva Fennica vol. 30 no. 2–3 article id 5593. https://doi.org/10.14214/sf.a9238

The present study is the first attempt to carry out an inventory of greenhouse gas (GHG) fluxes in the forests of Estonia. The emission and uptake of CO2 as a result of forest management, forest conversion and abandonment of cultivated lands in Estonia was estimated. The removal of GHG by Estonian forests in 1990 exceeded the release about 3.3 times. Changes in the species composition and productivity of forest sites under various simulated climate change scenarios have been predicted by using the Forest Gap Model for the central and coastal areas of Estonia. The computational examples showed that the changes in forest community would be essential.

  • Mandre, ORCID ID:E-mail:
  • Klõseiko, ORCID ID:E-mail:
  • Reisner, ORCID ID:E-mail:
  • Tullus, 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 5591, category Article
Egbert Beuker, Seppo Kellomäki, Marja Kolström. (1996). Changes in wood production of Picea abies and Pinus sylvestris under a warmer climate: comparison of field measurements and results of a mathematical model. Silva Fennica vol. 30 no. 2–3 article id 5591. https://doi.org/10.14214/sf.a9236

To project the changes in wood production of Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) in Finland as a result of climate change, two separate studies were made. The first study, at the Faculty of Forestry, University of Joensuu, based its projections on mathematical models; the second one, at the Finnish Forest Research Institute, based projections on measurements of wood production in two series of aged provenance experiments. The results of the two studies were similar for both species: after a 4°C increase of the annual mean temperature a drastic increase in wood production in northern Finland, but little effect, or even some decrease in the southern part of the country. However, the assumptions used in the two studies differed. One important difference was that in the models the temperature is assumed to be increasing gradually over the years, whereas in the provenance experiments, climate changed immediately when the seedlings were transferred to the planting sites. Another problem with the provenance experiments is that when material is moved in a north-south direction in Finland, not only temperature but also photoperiod changes markedly. To compare these two studies, site factors (e.g. soil type, temperature, precipitation) and silvicultural factors (e.g. plant spacing, survival, time of thinning, thinning intensity) from the provenance experiments were included a variable in the mathematical models.

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

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

  • Hänninen, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
  • Leinonen, ORCID ID:E-mail:
  • Repo, ORCID ID:E-mail:
article id 5587, category Article
Dina I. Nazimova, N.P. Polikarpov. (1996). Forest zones of Siberia as determined by climatic zones and their possible transformation trends under global change. Silva Fennica vol. 30 no. 2–3 article id 5587. https://doi.org/10.14214/sf.a9232

A system of zonality in Siberia has been formed under the control of continentality, which provides the heat and humidity regimes of the forest provinces. Three sectors of continentality and four to six boreal sub-zone form a framework for the systematization of the different features of land cover in Siberia. Their climatic ordination provides the fundamental basis for the principal potential forest types (composition, productivity) forecasting the current climate. These are useful in predicting the future transformations and succession under global change.

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

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

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

  • Monserud, ORCID ID:E-mail:
  • Denissenko, ORCID ID:E-mail:
  • Kolchugina, ORCID ID:E-mail:
  • Tchebakova, ORCID ID:E-mail:
article id 5584, category Article
Tarmo Virtanen, Seppo Neuvonen, Pekka Niemelä, Ari Nikula, Martti Varama. (1996). Climate change and the risks of Neodiprion sertifer outbreaks on Scots pine. Silva Fennica vol. 30 no. 2–3 article id 5584. https://doi.org/10.14214/sf.a9229

The European Pine Sawfly (Neodiprion sertifer Geoffroy) is one of the most serious defoliators of Scots pine (Pinus sylvestris L.) in northern Europe. We studied the pattern in the regional occurrence of the outbreaks of N. sertifer in Finland in years 1961-90, and made predictions about the outbreak pattern to the year 2050 after predicted winter warming. We tested whether minimum winter temperatures and forest type and soil properties could explain the observed outbreak pattern. We analysed outbreak patterns at two different spatial levels: forest board- and municipal-level.

The proportion of coniferous forests on damage-susceptible soils (dry and infertile sites) explained a significant part of the variation in outbreak frequency at small spatial scale (municipalities) but not at large spatial scale (forest boards). At the forest board level, the incidence of minimum temperatures below -36 °C (= the critical value for egg mortality) explains 33% of the variation in the outbreak pattern, and at the municipal level the incidence of cold winters was also the most significant explaining variable in northern Finland. Egg mortality due to cold winters seems to be the most parsimonious factor explaining why there have been so few N. sertifer outbreaks in northern and north-eastern Finland. We predict that climate change (increased winter temperatures) may increase the frequency of outbreaks in eastern and northern Finland in the future.

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

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

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

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

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

  • Ruel, ORCID ID:E-mail:
  • Ayres, ORCID ID:E-mail:
article id 5580, category Article
Virpi Palomäki, Toini Holopainen, Seppo Kellomäki, Kaisa Laitinen. (1996). First-year results on the effects of elevated atmospheric CO2 and O3 concentrations on needle ultrastructure and gas exchange responses of Scots pine saplings. Silva Fennica vol. 30 no. 2–3 article id 5580. https://doi.org/10.14214/sf.a9225

The effects of realistically elevated O3 and CO2 concentrations on the needle ultrastructure and photosynthesis of ca. 20-year-old Scots pine (Pinus sylvestris L.) saplings were studied during one growth period in open-top field chambers situated on a natural pine heath at Mekrijärvi, in eastern Finland. The experiment included six different treatments: chamberless control, filtered air, ambient air and elevated O3, CO2 and O3 + CO2. Significant increases in the size of chloroplast and starch grains were recorded in the current-year needles of the saplings exposed to elevated CO2 These responses were especially clear in the saplings exposed to elevated O3 + CO2 concentrations. These treatments also delayed the winter hardening process in cells. In the shoots treated with O3, CO2 and combined O3 + CO2 the Pmax was decreased on average by 50% (ambient CO2) and 40% (700 ppm CO2). Photosynthetic efficiency was decreased by 60% in all the treated shoots measured under ambient condition and by 30% in the CO2 and O3 + CO2 treated shoots under 700 ppm. The effect of all the treatments on photosynthesis was depressive which was probably related to evident accumulation of starch in the chloroplasts of the pines treated with CO2 and combined O3 + CO2. But in O3 treated pines, which did not accumulate starch in comparison to pines subjected to ambient air conditions, some injuries may be already present in the photosynthetic machinery.

  • Palomäki, ORCID ID:E-mail:
  • Holopainen, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
  • Laitinen, ORCID ID:E-mail:
article id 5579, category Article
F.G. Hall, P.J. Sellers, D.L. Williams. (1996). Initial results from the boreal ecosystem-atmosphere experiment, BOREAS. Silva Fennica vol. 30 no. 2–3 article id 5579. https://doi.org/10.14214/sf.a9224

BOREAS is a four-year, regional-scale experiment to study the forested continental interior of Canada. It aims at improving our understanding of the interaction between the earths' climate system and the boreal forests at short and intermediate time scales, in order to clarify their role in global change.

During the winter, spring and summer of 1994, five field campaigns were conducted. About 85 investigation teams including nearly 300 scientists participated, including forest ecologists and ecophysiologists, atmospheric physicists, boundary-layer meteorologists, hydrologists, biochemists, atmospheric chemists and remote sensing specialists.

The findings so far have been significant in terms of their implication for global change. The boreal ecosystem, occupying roughly 17 percent of the vegetated land surface and thus an important driver of global weather and climate, absorbs much more solar energy than is assumed by operational numerical weather prediction models. Albedo measurement show that this forest absorbs nearly 91% of the sun's incident energy. Additionally, while it is known that much of the boreal ecosystems consists of forested wetlands, lakes, bogs and fens, the measurements show that the atmosphere above was extremely dry; humidity and deep boundary layer convection (3,000 m) mimicked conditions found only over deserts. Physiological measurements of the trees show that this atmospheric desiccation was a result of the forests' strong biological control limiting surface evaporation. This tight control was linked to the low soil temperature and subsequently reduced rates of photosynthesis. BOREAS measurement also focused on net ecosystem carbon exchange. Data acquired during the late spring and summer, showed the boreal forests to be a net carbon sink. However, no measurements were taken in the early spring following thaw, and in the late fall, where the balance between photosynthesis and respiration is poorly understood. During 1996 additional data will be acquired to resolve the annual carbon budget and how it might depend on interannual climate differences.

  • Hall, ORCID ID:E-mail:
  • Sellers, ORCID ID:E-mail:
  • Williams, ORCID ID:E-mail:
article id 5533, category Article
Reijo Solantie. (1994). Effect of weather and climatological background on snow damage of forests in Southern Finland in November 1991. Silva Fennica vol. 28 no. 3 article id 5533. https://doi.org/10.14214/sf.a9173

Snow damage to forests in Southern Finland in November 1991 was examined in relation to meteorological conditions. The combined effect of different factors proved to be necessary for severe damage. First, the snow load, in terms of precipitation, should exceed a certain limit. The limit can be set for weak or moderate damage at about 40 mm and for very severe damage at about 60 mm. Second, temperature at the time of precipitation should be above 0°C, which enables the slightly wet snow to attach to twigs during the subsequent period with temperature below 0°C. On the other hand, temperatures exceeding 0.6°C prohibit damage by permitting the snow load to fall from the branches. Wind speed exceeding 9 ms-1, as observed 15 m above ground, were strong enough to dislodge the snow which is not attached, and thus reduce the damage. There are few statistics either of snow damage or of the relation between the snow damage and precipitation. However, there is causal connection between snow damage and heavy snowfalls. Therefore, the regions with a high frequency of heavy snowfalls, as indicated by orographical features and occurrence of thick snow cover, were investigated.

  • Solantie, ORCID ID:E-mail:
article id 7065, category Article
Aimo Kaarlo Cajander. (1921). Zur Frage der gegenseitigen Beziehungen zwischen Klima, Boden und Vegetation. Acta Forestalia Fennica vol. 21 no. 1 article id 7065. https://doi.org/10.14214/aff.7065
English title: The mutual relationship between the climate, the soil and the vegetation.

The article is based on the work “Metsänhoidon perusteet I” [The fundamentals of Forest management I] by the author (1919 in Finnish). The different processes of the soil and the vegetation are dependent on the climatic conditions, but also affect each other. The article presents the climatic zones of the earth and their most important characteristics in regard of cultivation of (to respective zone) exotic trees species and agriculture. 

  • Cajander, ORCID ID:E-mail:
article id 5239, category Article
Jussi Kuusipalo. (1985). On the use of tree stand parameters in estimating light conditions below the canopy. Silva Fennica vol. 19 no. 2 article id 5239. https://doi.org/10.14214/sf.a15418

Especially in forest vegetation studies, the light climate below the canopy is of great interest. In extensive forest inventories, direct measurement of the light conditions is too time-consuming. Often only the standard tree stand parameters are available. The present study was undertaken with the aim to develop methods for estimation of the light climate on the basis of readily measurable tree stand characteristics. The study material includes 40 sample plots representing different kinds of more or less mature forest stands of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.).

In each forest stand, a set of hemipherical photographs was taken and standard tree stand measurements were performed. A regression approach was applied in order to elaborate linear models for predicting the canopy coverage. The total basal area of the stand explained 63% of variance in the canopy coverage computed from hemipherical photographs. A coefficient representing the relative proportion of Norway spruce in the stand increased the explanatory power into 75%. When either the stand density (stems/unit area) or dominant age of the stand was included into the model, increment of the explanatory power into 80% was achieved. By incorporating both of the preceding predictors, an explanatory power of 85% was reached.

The PDF includes a summary in Finnish.

  • Kuusipalo, ORCID ID:E-mail:
article id 5237, category Article
Leo Heikurainen, Jukka Laine. (1985). Duration of the height growth response of young pine stands to NPK-fertilization on oligotrophic pine bogs in Finland. Silva Fennica vol. 19 no. 2 article id 5237. https://doi.org/10.14214/sf.a15416

This is the latest report in a series of publications from an on-going investigation which is concerned with the influence of different fertilization treatments and ditch spacings on the growth of Scots pine (Pinus sylvestris L.) seedlings and transplants growing on nutrient drained poor bogs in different parts of Finland. This paper concentrates on duration of the growth response to NPK-fertilization on the experimental plots. The experiment was established and the treatments performed in 1965–66.

The results show that climate, expressed as effective temperature sum (dd°C, threshold +5°C) has a clear influence on the duration of the fertilization effect. In Southern Finland (>1,200 dd°C), the duration was at least 15 years. In Central Finland (1,200–1,000 dd°C), it appears to be almost 10 years, and in Northern Finland (<1,000 dd°C), slightly shorter. The amount of fertilizer applied clearly influenced the duration of the fertilization effect. The dosage of 500 kg/ha (N 14, P 7.8, K 8.3 per cent) had, on average, a shorter duration than the greater dosages of 1,000 and 1,500 kg/ha. However, there was no clear difference between the latter two dosages.

The PDF includes a summary in Finnish.

  • Heikurainen, ORCID ID:E-mail:
  • Laine, ORCID ID:E-mail:
article id 7050, category Article
Lauri Ilvessalo. (1920). Ulkomaalaisten puulajien viljelymahdollisuudet Suomen oloja silmälläpitäen. Acta Forestalia Fennica vol. 17 no. 2 article id 7050. https://doi.org/10.14214/aff.7050
English title: Prospects of cultivating exotic tree species in Finland.

The article includes a dendrological review on the effect of climate to the success of cultivation of exotic tree species, based on literature and analysis of the existing Finnish field tests. The cultivation of an exotic tree species succeeds only if the seed has been procured from an area, which climate is similar to the place of cultivation. Climate is even more important than site quality.

Finnish climate is boreal and continental, and thus tree species of similar climate suit here best. In favorable site conditions it is possible to grow also species from boreal marine, and temperate climates. Finnish summers are not warm enough for species from temperate continental climate to get prepared for the winter, and the shoots can get frost damages. This may be compensated with a warm and sheltered site. If the species tolerates shading, it can be planted under sheltering trees. For species from maritime boreal climate, the Finnish summer tends to be too short, and the winters too cold. A suitable site is rich, warm and sheltered, and has preferably a protective sparse tree cover. Species from southern maritime climate cannot be grown in Finland. The provenance of the seeds is also very important. An important source of seeds are the successful plantations in Finland.

The PDF includes a summary in German.

  • Ilvessalo, ORCID ID:E-mail:
article id 5183, category Article
Risto Ojansuu, Helena Henttonen. (1983). Kuukauden keskilämpötilan, lämpösumman ja sademäärän paikallisten arvojen johtaminen Ilmatieteen laitoksen mittaustiedoista. Silva Fennica vol. 17 no. 2 article id 5183. https://doi.org/10.14214/sf.a15099
English title: Estimation of the local values of monthly mean temperature, effective temperature sum and precipitation sum from the measurements made by the Finnish Meteorological Office.

Methods involving the use of moving averages, trend surfaces and their combination are compared in deriving local values of monthly mean temperatures and precipitation sums from the observations made by the Finnish Meteorological Office. Correlation between meteorological variables and sea index, lake index and height above sea level were used in the trend surface method and in the combined method. Combined method, with a trend surface calculated from means of a long time period, was the most reliable method to estimate long local time series.

A method to calculate unbiased estimates of effective temperature sums from monthly mean temperatures is presented.

The PDF includes a summary in English.

  • Ojansuu, ORCID ID:E-mail:
  • Henttonen, ORCID ID:E-mail:
article id 5178, category Article
Reijo Solantie. (1983). "Mereisyyden - mantereisuuden" ja "humidisuuden" käsitteistä erityisesti tammen luontaisen levinneisyyden perusteella. Silva Fennica vol. 17 no. 1 article id 5178. https://doi.org/10.14214/sf.a15093
English title: Concepts of continentality-oceanity and humidity especially in the light of the natural distribution of Quercus robur.

Climatological factors determining the natural northern boundary in Europe of oak (Quercus robur L.) were investigated. The natural northern boundary of oak corresponds in detail to the curve at which the growing season, beginning at +5°C in spring and ending at +10°C in autumn, is of a certain constant length. The northern boundaries for more oceanic plants can be explained by prolonged autumn activity. This is obviously the general explanation or the concept of oceanity. Oak spread markedly in Finland in the summers during 1961–1975, which on an average were as warm but much dried than those during 1931–1960. The importance of humidity for oak was discussed.

The PDF includes a summary in English.

  • Solantie, ORCID ID:E-mail:
article id 7043, category Article
O. J. Lukkala. (1920). Tutkimuksia soiden kantokerroksista. Acta Forestalia Fennica vol. 16 no. 1 article id 7043. https://doi.org/10.14214/aff.7043
English title: Studies on stump layers in peatlands in Finland.
English keywords: peat profile; paludification; climate

The investigations that have studied peat layers in peatlands have shown that the peatlands in several countries have layers containing tree stumps of different tree species. The stump layers have been explained by local hydrological changes that have caused paludification, or changes in climate.

Peat layers were studied in drained peatlands in Finland, and ditches were used to study the peat profiles. A peatland in Multia in Central Finland was studied in more detail. Tree stump layer patterns that would support the climate change explanation was not found in the Finnish peatlands. The peat changes usually gradually more oligotrophic towards the surface. The stump layers seemed to be caused by local drier periods. According to the layers of Sphagnum-peat near the bottom of the peatlands and the pollen studies indicate that the peatlands have been formed at different times. In South-West Finland, the peat profiles had more apparent layer patterns than in Central Finland, but these were not considered to be caused by changes in climate.

The PDF includes a summary in German.

  • Lukkala, ORCID ID:E-mail:
article id 5015, category Article
Seppo Kellomäki. (1979). On geoclimatic variation in basic density of Scots pine wood. Silva Fennica vol. 13 no. 1 article id 5015. https://doi.org/10.14214/sf.a14869

The effect of temperature and water supply in the basic density of Scots pine (Pinus sylvestris L.) wood was studied on the basis of material obtained from the literature. On a monthly basis, the basic density increased with increasing mean temperature for June, July and August. The rainfall in these months had no detectable effect on the basic density except through the difference between rainfall and evaporation in July. On a yearly basis, the basic density increased with increasing mean temperature, temperature sum and length of growth period. The effect of water supply on the basic density was evident, and a linear relationship between basic density and annual rainfall was detected. The variation in basic density was, however, explained only partly by the chosen factors. Possible reasons for the poor explanatory power have been discussed.

The PDF includes a summary in Finnish.

  • Kellomäki, ORCID ID:E-mail:
article id 4905, category Article
Reijo Solantie. (1974). Kesän vesitaseen vaikutus metsä- ja suokasvillisuuteen ja linnustoon sekä lämpöolojen välityksellä maatalouden toimintaedellytyksiin Suomessa. Silva Fennica vol. 8 no. 3 article id 4905. https://doi.org/10.14214/sf.a14749
English title: The influence of water balance in summer on forest and peatland vegetation and bird fauna and through the temperature on agricultural conditions in Finland.

The significance of water budget in June and July for forest and peatland vegetation, and consequent effects on fauna, climate and agriculture has been studied.

In June, the difference between evaporation and precipitation is greater than it is later in the summer. North of the line zero difference of evaporation and precipitation, coinciding with a line of sharp change in forest vegetation, the uppermost part of podsol remains wet throughout the summer. During July, the line of zero difference moves from north to south over the greater part of Finland, run-off being minute and podsol at the driest in this month. This line, indicating the length of the period with evaporation greater than precipitation and causing a sharp change in forest vegetation, in frequency of peatlands, amount of growing stock productive capacity of forests etc. This line is significant also for cultivation: because of the lower evaporation north of this line, night temperature below the freezing point often appear in summer.

The PDF includes a summary in English.

  • Solantie, ORCID ID:E-mail:
article id 4754, category Article
Matti Leikola. (1967). Havaintoja erään hoidetun männikön tuulisuhteista. Silva Fennica vol. 1 no. 3 article id 4754. https://doi.org/10.14214/sf.a14538
English title: Observations on wind conditions in a managed Scots pine stand.

An explorative study on wind conditions in a well-managed Scots pine (Pinus sylvestris L.) stand was made in Southern Finland. The wind velocity was recorded continually with two cup anomometers from April to August, 1964. The two levels used were 2 m and 9 m. The wind velocity was lower at 2 m than within the canopy at 9 m. The dependence on the absolute wind velocity at 9 metres was logarithmic. The wind velocity did affect the difference between daily minimum temperatures at the two levels; the difference in the maximum temperatures was affected only in May and August.

The PDF includes a summary in English.

  • Leikola, ORCID ID:E-mail:
article id 4754, category Article
Matti Leikola. (1967). Havaintoja erään hoidetun männikön tuulisuhteista. Silva Fennica vol. 1 no. 3 article id 4754. https://doi.org/10.14214/sf.a14538
English title: Observations on wind conditions in a managed Scots pine stand.

An explorative study on wind conditions in a well-managed Scots pine (Pinus sylvestris L.) stand was made in Southern Finland. The wind velocity was recorded continually with two cup anomometers from April to August, 1964. The two levels used were 2 m and 9 m. The wind velocity was lower at 2 m than within the canopy at 9 m. The dependence on the absolute wind velocity at 9 metres was logarithmic. The wind velocity did affect the difference between daily minimum temperatures at the two levels; the difference in the maximum temperatures was affected only in May and August.

The PDF includes a summary in English.

  • Leikola, ORCID ID:E-mail:
article id 7606, category Article
Kari Heliövaara, Rauno Väisänen, Auli Immonen. (1991). Quantitative biogeography of the bark beetles (Coleoptera, Scolytidae) in northern Europe. Acta Forestalia Fennica no. 219 article id 7606. https://doi.org/10.14214/aff.7606

Biogeographical patterns of the Scolytidae in Fennoscandia and Denmark, based on species incidence data from the approximately 70 km x 70 km quadrats (n = 221) used by Lekander et al. (1977), were classified to environmental variables using multivariate methods (two-way indicator species analysis, detrended correspondence analysis, canonical correspondence analysis).

The distributional patterns of scolytid species composition showed similar features to earlier presented zonations based on vegetation composition. One major difference, however, was that the region was more clearly divided in an east-west direction. Temperature variables associated with the location of the quadrat had the highest canonical coefficient values on the first axis of the CCA. Although these variables were the most important determinants of the biogeographical variation in the beetle species assemblages, annual precipitation and the distribution of Picea abies also improved the fit of the species data.

Samples with the most deviant rarity and typicality indices for the scolytid species assempblages in each quadrat were concentrated in several southern Scandinavian quadrats, in some quadrats in northern Sweden, and especially on the Swedish islands (Öland, Gotland, Gotska Sandön) in the Baltic Sea. The use of rarity indices which do not take the number of species per quadrat, also resulted high values for areas near Stockholm and Helsinki with well-known faunas. Methodological tests in which the real changes in the distribution of Ips acuminatus and I. amitinus were used as indicators showed that the currently available multivariate methods are sensitive to small faunal shifts even, and thus permit analysis of the fauna in relation to environmental changes. However, this requires more detailed monitoring of the species’ distributions over longer time spans.

Distribution of seven species (Scolytus intricatus, S. laevis, Hylurgops glabratus, Crypturgus cinereus, Pityogenes salasi, Ips typographus, and Cyleborus dispar) were predicted by logistic regression models using climatic variables. In spite of the deficiencies in the data and the environmental variables selected, the models were relatively good for several but not for all species. The potential effects of climate change on bark beetles are discussed.

The PDF includes a summary in Finnish.

  • Heliövaara, ORCID ID:E-mail:
  • Väisänen, ORCID ID:E-mail:
  • Immonen, 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.

The PDF includes a summary in Finnish.

  • Chung, ORCID ID:E-mail:

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