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Articles containing the keyword 'stress'.

Category: Research article

article id 10002, category Research article
Bayasaa Tumenjargal, Futoshi Ishiguri, Haruna Aiso-Sanada, Yusuke Takahashi, Bayartsetseg Baasan, Ganbaatar Chultem, Jyunichi Ohshima, Shinso Yokota. (2018). Geographic variations of wood properties of Larix sibirica naturally grown in Mongolia. Silva Fennica vol. 52 no. 4 article id 10002. https://doi.org/10.14214/sf.10002
Highlights: Significant differences (p  < 0.01) among five stands were found in tree height, stress-wave velocity of stems, dynamic Young’s modulus of stems and logs, annual ring width, and latewood percentage, suggesting that there was geographic variation of mechanical properties of wood in Larix sibirica (Münchh.) Ledeb. grown in Mongolia; Dynamic Young’s modulus of logs in L. sibirica trees can be predicted by stress-wave velocity of stems; Stem diameter of L. sibirica naturally grown in Mongolia is closely related to radial growth at initial stage of growth, especially within the first twenty years.

Geographic variations in growth, stress-wave velocity of stem, dynamic Young’s modulus of stems and logs, annual ring width, latewood percentage and basic density were investigated for Larix sibirica (Münchh.) Ledeb. naturally grown in Mongolia. A total of 250 trees with 20 to 30 cm in stem diameter at a height of 1.3 m above ground level were selected from each natural stand in five different provenances in Mongolia. In addition, five trees in each stand were cut for measuring dynamic Young’s modulus of stems and logs, annual ring width, latewood percentage and basic density. Mean values of stress-wave velocity of stems in each stand ranged from 2.92 to 3.41 km s–1, and the mean value of five stands was 3.23 km s–1. Mean values of dynamic Young’s modulus of logs in each stand ranged from 5.17 to 9.72 GPa. A significant correlation (r = 0.798, p < 0.01) was found between stress-wave velocity of stems and dynamic Young’s modulus of logs. Among the five stands, the highest and the lowest values of average annual ring number were 193 and 44, respectively. Mean values of basic density in five trees within each stand were examined and ranged from 0.52 to 0.56 g cm–3. Significant differences among five stands were found in tree height, stress-wave velocity of stem, dynamic Young’s modulus of stems and logs, annual ring width and latewood percentage, suggesting that L. sibirica trees naturally grown in Mongolia have geographic variations in mechanical properties of wood.

  • Tumenjargal, Faculty of Agriculture, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan; United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan; Research and Training Institute of Forestry and Wood Industry, Mongolian University Science and Technology, Ulaanbaatar 14191, Mongolia ORCID ID:E-mail: t_bayasaa88@yahoo.com
  • Ishiguri, Faculty of Agriculture, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan ORCID ID:E-mail: ishiguri@cc.utsunomiya-u.ac.jp (email)
  • Aiso-Sanada, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan ORCID ID:E-mail: haiso@ffpri.affrc.go.jp
  • Takahashi, Faculty of Agriculture, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan ORCID ID:E-mail: zo.r.by0814@gmail.com
  • Baasan, Research and Training Institute of Forestry and Wood Industry, Mongolian University Science and Technology, Ulaanbaatar 14191, Mongolia ORCID ID:E-mail: bayartsetseg@must.edu.mn
  • Chultem, Research and Training Institute of Forestry and Wood Industry, Mongolian University Science and Technology, Ulaanbaatar 14191, Mongolia ORCID ID:E-mail: t_bayasaa88@yahoo.com
  • Ohshima, Faculty of Agriculture, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan ORCID ID:E-mail: joshima@cc.utsunomiya-u.ac.jp
  • Yokota, Faculty of Agriculture, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan ORCID ID:E-mail: yokotas@cc.utsunomiya-u.ac.jp
article id 1295, category Research article
Jiaxi Wang, Guolei Li, Jeremiah R. Pinto, Jiajia Liu, Wenhui Shi, Yong Liu. (2015). Both nursery and field performance determine suitable nitrogen supply of nursery-grown, exponentially fertilized Chinese pine. Silva Fennica vol. 49 no. 3 article id 1295. https://doi.org/10.14214/sf.1295
Highlights: Increasing exponential fertilization rates in the nursery increased seedling biomass, N content, and N concentration for Chinese pine seedlings; Second year seedling survival illustrated a curvilinear response to seedling fertilization rates rather than a linear one; Considering both nursery responses to fertilization and field performance after two years yielded a recommended nitrogen supply rate of 80 mg N seedling–1.
Optimum fertilization levels are often determined solely from nursery growth responses. However, it is the performance of the seedling on the outplanting site that is the most important. For Pinus species seedlings, little information is known about the field performance of plants cultured with different nutrient rates, especially with exponential fertilization. In this study, Chinese pine (Pinus tabulaeformis Carr.) seedlings grown in 187 ml containers were fertilized exponentially in 6 treatments ranging from 10 to 120 mg N seedling–1 for 25 weeks before outplanting. Dry mass and N content were measured at planting. Survival and field growth were monitored for two growing seasons. In the nursery, our data showed no difference in dry mass among the 40, 80, 100, and 120 mg N seedling–1 fertilizer treatments; collectively, these treatments were significantly greater than at 10 and 20 mg N seedling–1 treatments. Seedling N content was greatest for the 100 and 120 mg N seedling–1 rates. These data suggested that nursery optimum N fertilization rate was no less than 100 mg N seedling–1. Outplanting height and root-collar diameter growth characteristics were not significantly different after two years, whereas maximum mean survival was best for seedlings nursery-fertilized at 80 mg N seedling–1. In consideration of both nursery and field performance metrics, our data suggest that exponentially fertilizing Chinese pine seedlings at 80 mg N seedling–1 maximizes both nursery biomass accumulation and outplanting survival.
  • Wang, Key Laboratory for Silviculture and Conservation, Ministry of Education, Beijing Forestry University, 35 East Qinghua Road, Haidian District, Beijing 100083, China ORCID ID:E-mail: wjx198979@163.com
  • Li, Key Laboratory for Silviculture and Conservation, Ministry of Education, Beijing Forestry University, 35 East Qinghua Road, Haidian District, Beijing 100083, China ORCID ID:E-mail: glli226@163.com (email)
  • Pinto, US Department of Agriculture, Forest Service, Rocky Mountain Research Station, 1221 South Main Street, Moscow, ID 83843, USA ORCID ID:E-mail: jpinto@fs.fed.us
  • Liu, Key Laboratory for Silviculture and Conservation, Ministry of Education, Beijing Forestry University, 35 East Qinghua Road, Haidian District, Beijing 100083, China ORCID ID:E-mail: 1044902638@qq.com
  • Shi, Key Laboratory for Silviculture and Conservation, Ministry of Education, Beijing Forestry University, 35 East Qinghua Road, Haidian District, Beijing 100083, China ORCID ID:E-mail: shiwenhui2008@163.com
  • Liu, Key Laboratory for Silviculture and Conservation, Ministry of Education, Beijing Forestry University, 35 East Qinghua Road, Haidian District, Beijing 100083, China ORCID ID:E-mail: lyong@bjfu.edu.cn
article id 1176, category Research article
Batoul Al-Hawija, Viktoria Wagner, Monika Partzsch, Isabell Hensen. (2014). Germination differences between natural and afforested populations of Pinus brutia and Cupressus sempervirens. Silva Fennica vol. 48 no. 4 article id 1176. https://doi.org/10.14214/sf.1176
Highlights: Silvicultural practices of raising and outplanting seedlings yielded contrasting outcomes in our species; Afforested Pinus brutia populations acquired ability to tolerate drought stress at intermediate and hot temperatures compared to natural populations, which may indicate local adaptation; Natural Cupressus sempervirens populations showed higher salt-tolerance than afforested populations; Seed germination was optimal under intermediate temperatures and deionized water for both species.
In afforestation, silvicultural processes of raising and planting seedlings under certain conditions can yield contrasting outcomes in tree stock performance. Moderate nursery conditions may select against stress tolerance whereas planting seedlings in stressful environments at afforestation sites may select for higher stress tolerance compared to natural populations. We compared germination performance between natural and afforested populations of Pinus brutia Ten. subsp. brutia and Cupressus sempervirens L. var. horizontalis (Mill.) under differing stress treatments. Seeds were collected from both natural stands and from afforested populations outside the natural distribution range, in Syria. Cold, intermediate and hot temperature regimes were simulated (8/4 °C, 20/10 °C and 32/20 °C) along with cold stratification, drought stress (–0.2 and –0.4 MPa), salt stress (50 and 100 mMol l–1), and deionized water (control) conditions. In addition, we tested the effects of seed weight and climatic conditions on seed germination. In general, intermediate temperatures were optimal for both population types. Afforested P. brutia populations outperformed natural ones under drought stress levels at hot and/or intermediate temperatures. Conversely, in C. sempervirens, cold stratification at all temperatures and higher salt stress at intermediate temperatures significantly decreased germination in afforested populations. Seed weight did not significantly affect germination percentages, which were however significantly negatively related to annual precipitation in P. brutia, and to annual temperature in C. sempervirens. We infer that silvicultural processes led to divergent outcomes in our species: local adaptation to drought stress and hot temperatures in afforested P. brutia populations and lower salt-stress tolerance in C. sempervirens.
  • Al-Hawija, Martin-Luther-University Halle-Wittenberg, Institute of Biology/Geobotany and Botanical Garden, Am Kirchtor 1, D-06108 Halle/Saale, Germany ORCID ID:E-mail: batoulh@gmail.com (email)
  • Wagner, Department of Botany and Zoology, Masaryk University, Kotlářská 2, CZ-611 37 Brno, Czech Republic ORCID ID:E-mail: wagner@sci.muni.cz
  • Partzsch, Martin-Luther-University Halle-Wittenberg, Institute of Biology/Geobotany and Botanical Garden, Am Kirchtor 1, D-06108 Halle/Saale, Germany ORCID ID:E-mail: monika.partzsch@botanik.uni-halle.de
  • Hensen, Martin-Luther-University Halle-Wittenberg, Institute of Biology/Geobotany and Botanical Garden, Am Kirchtor 1, D-06108 Halle/Saale, Germany & German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany ORCID ID:E-mail: isabell.hensen@botanik.uni-halle.de
article id 1176, category Research article
Batoul Al-Hawija, Viktoria Wagner, Monika Partzsch, Isabell Hensen. (2014). Germination differences between natural and afforested populations of Pinus brutia and Cupressus sempervirens. Silva Fennica vol. 48 no. 4 article id 1176. https://doi.org/10.14214/sf.1176
Highlights: Silvicultural practices of raising and outplanting seedlings yielded contrasting outcomes in our species; Afforested Pinus brutia populations acquired ability to tolerate drought stress at intermediate and hot temperatures compared to natural populations, which may indicate local adaptation; Natural Cupressus sempervirens populations showed higher salt-tolerance than afforested populations; Seed germination was optimal under intermediate temperatures and deionized water for both species.
In afforestation, silvicultural processes of raising and planting seedlings under certain conditions can yield contrasting outcomes in tree stock performance. Moderate nursery conditions may select against stress tolerance whereas planting seedlings in stressful environments at afforestation sites may select for higher stress tolerance compared to natural populations. We compared germination performance between natural and afforested populations of Pinus brutia Ten. subsp. brutia and Cupressus sempervirens L. var. horizontalis (Mill.) under differing stress treatments. Seeds were collected from both natural stands and from afforested populations outside the natural distribution range, in Syria. Cold, intermediate and hot temperature regimes were simulated (8/4 °C, 20/10 °C and 32/20 °C) along with cold stratification, drought stress (–0.2 and –0.4 MPa), salt stress (50 and 100 mMol l–1), and deionized water (control) conditions. In addition, we tested the effects of seed weight and climatic conditions on seed germination. In general, intermediate temperatures were optimal for both population types. Afforested P. brutia populations outperformed natural ones under drought stress levels at hot and/or intermediate temperatures. Conversely, in C. sempervirens, cold stratification at all temperatures and higher salt stress at intermediate temperatures significantly decreased germination in afforested populations. Seed weight did not significantly affect germination percentages, which were however significantly negatively related to annual precipitation in P. brutia, and to annual temperature in C. sempervirens. We infer that silvicultural processes led to divergent outcomes in our species: local adaptation to drought stress and hot temperatures in afforested P. brutia populations and lower salt-stress tolerance in C. sempervirens.
  • Al-Hawija, Martin-Luther-University Halle-Wittenberg, Institute of Biology/Geobotany and Botanical Garden, Am Kirchtor 1, D-06108 Halle/Saale, Germany ORCID ID:E-mail: batoulh@gmail.com (email)
  • Wagner, Department of Botany and Zoology, Masaryk University, Kotlářská 2, CZ-611 37 Brno, Czech Republic ORCID ID:E-mail: wagner@sci.muni.cz
  • Partzsch, Martin-Luther-University Halle-Wittenberg, Institute of Biology/Geobotany and Botanical Garden, Am Kirchtor 1, D-06108 Halle/Saale, Germany ORCID ID:E-mail: monika.partzsch@botanik.uni-halle.de
  • Hensen, Martin-Luther-University Halle-Wittenberg, Institute of Biology/Geobotany and Botanical Garden, Am Kirchtor 1, D-06108 Halle/Saale, Germany & German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103 Leipzig, Germany ORCID ID:E-mail: isabell.hensen@botanik.uni-halle.de
article id 121, category Research article
Catherine Ky-Dembele, Jules Bayala, Patrice Savadogo, Mulualem Tigabu, Per Christer Odén, Issaka Joseph Boussim. (2010). Comparison of growth responses of Khaya senegalensis seedlings and stecklings to four irrigation regimes. Silva Fennica vol. 44 no. 5 article id 121. https://doi.org/10.14214/sf.121
Khaya senegalensis is an important tree species for timber production, native to West Africa, but mahogany shoot borer attacks prevent successful plantations. This research was aimed at comparing the growth of two propagule types, seedlings and stecklings, of Khaya senegalensis subjected to four irrigation regimes, 25, 50, 75 and 100% field capacity in Burkina Faso. The relative growth rate, biomass allocation and intrinsic water use efficiency of the propagules were assessed in a full-factorial pot experiment in block design. Except the relative growth rate of stem basal diameter and specific leaf area, for which mean values were significantly higher for seedlings than stecklings, the two propagule types had similar growth patterns regarding relative growth rates of stem length, leaf, stem, root and the total plant biomass. There was no significant difference between propagule types concerning biomass fraction to total plant biomass of leaf, stem and root, root to stem ratio, leaf area productivity and carbon isotope ratio (δ13C). However, the irrigation regimes significantly affected all parameters. In contrast to 75 and 100% field capacity irrigation regimes, the low water supply of 25 and 50% field capacity resulted in plant stress, which was evident from the significant reduction in plant growth and biomass production and an increase in the root biomass to total plant biomass ratio and δ13C. It can be concluded that seedlings and stecklings have comparable growth patterns, while water stress is a major growth-limiting factor highlighting the need for selecting drought and borer resistant genotypes for successful plantations.
  • Ky-Dembele, Département Productions Forestières, Institut de l’Environnement et de Recherches Agricoles, 03 BP 7047 Ouagadougou 03, Burkina Faso & Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 101, SE-230 53 Alnarp, Sweden (catherine.dembele@slu.se) ORCID ID:E-mail: kydembele@hotmail.com (email)
  • Bayala, World Agroforestry Centre, West Africa and Centre Regional Office, Sahel Node, BP E5118 Bamako, Mali ORCID ID:E-mail:
  • Savadogo, Département Productions Forestières, Institut de l’Environnement et de Recherches Agricoles, 03 BP 7047 Ouagadougou 03, Burkina Faso & Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 101, SE-230 53 Alnarp, Sweden ORCID ID:E-mail:
  • Tigabu, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 101, SE-230 53, Alnarp, Sweden ORCID ID:E-mail:
  • Odén, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 101, SE-230 53, Alnarp, Sweden ORCID ID:E-mail:
  • Boussim, Université de Ouagadougou, Unité de Formation et Recherche en Sciences de la Vie et de la Terre, 03 BP 7021, Ouagadougou 03, Burkina Faso ORCID ID:E-mail:
article id 160, category Research article
Fan Yang, Ling-Feng Miao. (2010). Adaptive responses to progressive drought stress in two poplar species originating from different altitudes. Silva Fennica vol. 44 no. 1 article id 160. https://doi.org/10.14214/sf.160
Cuttings of Populus kangdingensis C. Wang et Tung and Populus cathayana Rehder, originating from high and low altitudes in the eastern Himalaya, respectively, were examined during one growing season in a greenhouse to determine the effects of progressive drought stress. The results manifested that the adaptive responses to progressive drought stress were different in these two species from different altitudes. Significant changes in stem height, leaf development, relative water content (RWC), malondialdehyde (MDA) and hydrogen peroxide (H2O2) appeared earlier in P. cathayana than in P. kangdingensis, whereas changes in soluble protein, soluble sugar, free proline and antioxidant enzymes appeared earlier in P. kangdingensis. In addition, changes in these parameters became more and more significant when the drought stress progressed, especially under severe drought stress in P. cathayana. Plant growth showed significant positive correlations with soluble proteins and sugars, free proline and antioxidants and a significant negative correlation with RWC under water stressed treatment in two poplar species. Compared with P. cathayana, P. kangdingensis was able to maintain a superior height growth and leaf development under drought stress. Also, P. kangdingensis possessed greater increments in soluble protein, soluble sugar, free proline and antioxidant enzymes, but lower increments in MDA and H2O2 than did P. cathayana when the cuttings were exposed to progressive drought stress. Our results suggest that P. kangdingensis originating from the high altitude has a better drought tolerance than does P. cathayana originating from the low altitude. Furthermore, this study manifested that acclimation to drought stress are related the rapidity, severity, duration of the drought event and the altitude of two poplar species.
  • Yang, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, P. R. China (yangfan@wbgcas.cn) & Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu, Sichuan 610041, P. R. China ORCID ID:E-mail: fanyangmlf6303@163.com (email)
  • Miao, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei 430071, P. R. China ORCID ID:E-mail:
article id 187, category Research article
Tobias Biechele, Leif Nutto, Gero Becker. (2009). Growth strain in Eucalyptus nitens at different stages of development. Silva Fennica vol. 43 no. 4 article id 187. https://doi.org/10.14214/sf.187
Eucalypts are renowned for their high growth stress levels. These stresses cause splitting, warping and dimensional instability when cutting, processing and drying the wood. In Chile, large Eucalyptus nitens plantations can be found, which, due to these problems, are scarcely utilised for solid wood products (veneer, sawn wood). This study aims to determine the factors influencing growth stress at different stages of tree’s development, and to identify whether the factors influencing growth stress change over time. In five stands of different ages, growth strain, as an indicator of growth stress, was measured at different tree heights with the single hole drilling method. The tree variables DBH, tree height, slenderness (height/diameter ratio) and crown parameters also were measured. A correlation analysis of tree variables and growth strains was undertaken. The results obtained indicate a high variability in growth strain values. It was concluded that growth strain is not correlated with a single growth parameter, but with a combination of factors that variously influence it at different ages and tree heights.
  • Biechele, University of Freiburg, Institute of Forest Utilisation and Work Science, Werthmannstr. 6, DE-79085 Freiburg, Germany ORCID ID:E-mail: tobias.biechele@fobawi.uni-freiburg.de (email)
  • Nutto, University of Freiburg, Institute of Forest Utilisation and Work Science, Werthmannstr. 6, DE-79085 Freiburg, Germany ORCID ID:E-mail:
  • Becker, University of Freiburg, Institute of Forest Utilisation and Work Science, Werthmannstr. 6, DE-79085 Freiburg, Germany ORCID ID:E-mail:
article id 212, category Research article
Sandhya Samarasinghe. (2009). Exploration of fracture dynamics properties and predicting fracture toughness of individual wood beams using neural networks. Silva Fennica vol. 43 no. 2 article id 212. https://doi.org/10.14214/sf.212
In this study, the time to crack initiation (Tinit), duration of crack propagation (Tfrac), crack initiation stress, peak stress as well as crack speed and fracture toughness were investigated for three Rates of Loading (ROL) and four sizes of notched wood beams using high-speed video imaging and neural networks. Tinit was consistent for all volumes and the average Tinit was nonlinearly related to volume and ROL. For the smallest ROL, there was a distinct volume effect on Tinit and the effect was negligble at the largest ROL. However, the stress at crack initiation was not consistent. Contrasting these, Tfrac for all volumes appeared to be highly variable but the peak stress carried prior to catastrophic failure was consistent. The crack propagation was a wave phenomenon with positive and negative (crack closure) speeds that varied with the ROL. As accurate estimation of crack initiation load (or stress) and its relationship to peak load (or stress) is important for determining fracture toughness, Artificial Neural Networks (ANN) models were developed for predicting them from volume, Young’s modulus, face and grain angles, density, moisture content and ROL. Models for crack initiation load and peak load showed much higher predictive power than those for the stresses with correlation coefficients of 0.85 and 0.97, respectively, between the actual and predicted loads. Neural networks were also developed for predicting fracture toughness of individual wood specimens and the best model produced a statistically significant correlation of 0.813 between the predicted and actual fracture toughness on a validation dataset. The inputs captured 62% of variability of fracture toughness. Volume and Young’s modulus were the top two contributing variables with others providing lesser contributions.
  • Samarasinghe, Centre for Advanced Computational Solutions (C-fACS), Lincoln University, Canterbury, New Zealand ORCID ID:E-mail: sandhya.samarasinghe@lincoln.ac.nz (email)
article id 293, category Research article
Conor O'Reilly, Norberto De Atrip. (2007). Seed moisture content during chilling and heat stress effects after chilling on the germination of common alder and downy birch seeds. Silva Fennica vol. 41 no. 2 article id 293. https://doi.org/10.14214/sf.293
The effects of seed moisture content (MC) and heat treatment on the germination response of common alder (Alnus glutinosa) and downy birch (Betula pubescens) seeds were examined. Seeds of each species were adjusted to MC of 7% to 50% MC, then chilled for up to 36 weeks, after which they were allowed to germinate at 15°C with 8 hours lighting per day or 20 (dark)/ 30°C (light). Seed lot effects were evident, but treatment effects were consistent in each lot and species. The response to moist chilling treatments was larger at 15°C than at 20/30°C. Chilling had no effect on germination unless seed MC was >15%, but it was low also at 20% MC. The highest germination was achieved following 24–36 weeks chilling at the optimum or target MC (TMC) levels of about 30% in alder and 35% in birch. In a separate experiment, seeds were fully imbibed (FI) (~50% MC; standard method used in operational practice) or adjusted to TMC levels, after which some seeds of each treatment group were chilled to release dormancy. Following this, the seeds were dried back to TMC levels and then subjected to 60°C for up to 4 hours after which they were allowed germinate under the same conditions described above. Heat treatment damaged the prechilled FI seeds, but no damage occurred to the non-chilled seeds. However, heat stress stimulated germination in the non-chilled FI seeds of both species and the TMC seeds of alder.
  • O'Reilly, UCD School of Biology and Environmental Science, UCD College of Life Sciences, University College Dublin, Belfield, Dublin 4, Ireland ORCID ID:E-mail: conor.oreilly@ucd.ie (email)
  • De Atrip, UCD School of Biology and Environmental Science, UCD College of Life Sciences, University College Dublin, Belfield, Dublin 4, Ireland ORCID ID:E-mail:
article id 382, category Research article
Steen Magnussen, René I. Alfaro, Paul Boudewyn. (2005). Survival-time analysis of white spruce during spruce budworm defoliation. Silva Fennica vol. 39 no. 2 article id 382. https://doi.org/10.14214/sf.382
Mortality and defoliation (DF%) in 987 white spruce (Picea glauca (Moench) Voss) trees were followed from 1992 to 2003 during an outbreak of the spruce budworm Choristoneura fumiferana (Clem.) in 15 white-spruce-dominated uneven-aged stands in the Fort Nelson Forest District near Prince George, British Columbia. Four stands were aerially sprayed with Bacillus thuringiensis (Bt). Defoliation and mortality levels were elevated in non-sprayed stands. The relationship between defoliation and survival-times was captured in a Cox proportional hazard model with a defoliation stress index (DSI), diameter (DBH), crown class (CCL), a random stand effect, Bt-treatment, and number of years of exposure to stand-level defoliation (DYEAR) as predictors. The DSI, optimized for discrimination between survivors and non-survivors, is the discounted sum of five lagged DF% values. Survival probabilities were predicted with a maximum error of 0.02. Hazard rates increased by 0.06 for every one point increase in DSI. CCL and random stand effects were highly significant. Bt-treatment effects were fully captured by DSI, CCL, and DYEAR.
  • Magnussen, Canadian Forest Service, Victoria, BC, Canada. V8Z 1M5 ORCID ID:E-mail: smagnussen@pfc.forestry.ca (email)
  • Alfaro, Canadian Forest Service, Victoria, BC, Canada. V8Z 1M5 ORCID ID:E-mail:
  • Boudewyn, Canadian Forest Service, Victoria, BC, Canada. V8Z 1M5 ORCID ID:E-mail:
article id 415, category Research article
Sandhya Samarasinghe, Don Kulasiri. (2004). Stress intensity factor of wood from crack-tip displacement fields obtained from digital image processing. Silva Fennica vol. 38 no. 3 article id 415. https://doi.org/10.14214/sf.415
Stress intensity factor of radiata pine (Pinus radiata) in Tangential-Longitudinal opening mode was determined from crack-tip displacement fields obtained from digital image correlation in conjunction with orthotropic fracture theory. For lower loads, experiments agreed with the linear elastic fracture theory but for higher loads, stress intensity factor and load relationship was nonlinear. For 41% of the specimens tested, tip-displacement based stress intensity factor agreed with that based on the ASTM standard formula for lower loads but deviated for higher loads closer to failure. The tip displacement plots showed that the nonlinear behaviour is due to large displacements which we attributed to large plastic deformations and/or micro-cracking in this region. The other 59% specimens showed a similar trend except that the crack-tip based stress intensity factor was consistently higher than the value obtained from the standard formula. The fracture toughness from tip displacements was larger than the standard values for all specimens and the two were related by a logarithmic function with an R2 of 0.61. The study also established that fracture toughness increases with the angle of inclination of the original crack plane to the Radial Longitudinal plane.
  • Samarasinghe, Lincoln University, P.O. Box 84, Canterbury, New Zealand ORCID ID:E-mail:
  • Kulasiri, Lincoln University, P.O. Box 84, Canterbury, New Zealand ORCID ID:E-mail: kulasird@lincoln.ac.nz (email)
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:

Category: Article

article id 5633, category Article
Seppo Kaunisto, Tytti Sarjala. (1997). Critical needle potassium concentrations indicated by diamine putrescine in Norway spruce growing on peat soils. Silva Fennica vol. 31 no. 4 article id 5633. https://doi.org/10.14214/sf.a8535

Dormant needles from 129 Norway spruce (Picea abies (L.) H. Karst.) trees from the 2nd and 3rd topmost whorls were collected from spruce stands locating fairly close to each other. Tree height varied from 8 to 25 metres. Trees with and without visual potassium deficiency symptoms in needles were selected and analysed for nitrogen, phosphorus, potassium, magnesium, boron, copper, zinc, and 3 free polyamines putrescine, spermine and spermidine.

The concentrations of all the analysed nutrients ranged from deficient to satisfactory levels. Free putrescine, spermidine and spermine concentrations in the current needles had a wide variation between the trees. Spermidine had a positive and spermine a negative correlation with potassium. Putrescine had a strong negative correlation with potassium with statistically significant increase in putrescine starting at potassium concentrations below 5.4 mg/g dry weight. The regression between putrescine and potassium changed from a linear to a non-linear form at the potassium concentration of 4.2–4.6 mg/g dry weight representing a severe K deficiency limit. The corresponding K/P ratio was 2.6–2.7. Extremely low phosphorus concentrations (P < 1.0 mg/g) lowered putrescine concentrations, but otherwise the relationships between putrescine, spermidine or spermine and potassium concentrations were unaffected by tree nutrition. At adequate potassium levels the putrescine concentrations were only slightly lower in trees taller than 20 metres than in trees of 8–16 metres height. The results show that the needle putrescine concentration can be used quite reliably for describing potassium nutrition of Norway spruce in varying nutritional and tree size conditions.

  • Kaunisto, ORCID ID:E-mail:
  • Sarjala, ORCID ID:E-mail:
article id 5625, category Article
Thomas Früh. (1997). Simulation of water flow in the branched tree architecture. Silva Fennica vol. 31 no. 3 article id 5625. https://doi.org/10.14214/sf.a8526

The model HYDRA, which simulates water flow in the branched tree architecture, is characterized. Empirical studies of the last decades give strong evidence for a close structure-function linkage in the case of tree water flow. Like stomatal regulation, spatial patterns of leaf specific conductivity can be regarded as a strategy counteracting conductivity losses, which may arise under drought. Branching-oriented water flow simulation may help to understand how damaging and compensating mechanisms interact within the hydraulic network of trees. Furthermore, a coupling of hydraulic to morphological modelling is a prerequisite if water flow shall be linked to other processes. Basic assumptions of the tree water flow model HYDRA are mass conservation, Darcy's law and the spatial homogeneity of capacitance and axial conductivity. Soil water potential is given as a one-sided border condition. Water flow is driven by transpiration. For unbranched regions these principles are condensed to a nonlinear diffusion equation, which serves as a continuous reference for the discrete method tailored to the specific features of the hydraulic network. The mathematical derivation and model tests indicate that the realization of the basic assumptions is reproducible and sufficiently exact. Moreover, structure and function are coupled in a flexible and computationally efficient manner. Thus, HYDRA may serve as a tool for the comparative study of different tree architectures in terms of hydraulic function.

  • Früh, ORCID ID:E-mail:
article id 5549, category Article
Kari Leinonen, Hannu Rita. (1995). Interaction of prechilling, temperature, osmotic stress, and light in Picea abies seed germination. Silva Fennica vol. 29 no. 2 article id 5549. https://doi.org/10.14214/sf.a9200

A multi-factor experimental approach and proportional odds model were used to study interactions between five environmental factors significant to Norway spruce (Picea abies (L.) H. Karst.) seed germination: prechilling (at +4.5°C), suboptimal temperatures (+12 and +16°C), osmotically induced water stress (0.3 Mpa and 0 Mpa), prolonged white light, and short-period of far-red light. Temperature and osmotic stress interacted with one another in the germination of seeds; the effect off osmotic stress being stronger at +16°C than at +12°C. In natural conditions, this interaction may prevent germination early in the summer when soil dries and temperature increases. Prolonged white light prevented germination at low temperature and low osmotic potential. Inhibitory effect was less at higher temperatures and higher osmotic potential, as well as after prechilling. Short-period far-red light did not prevent germination of unchilled seeds in darkness. Prechilling tended to make seeds sensitive to short pulses of far-red light, an effect which depended on temperature: at +12°C the effect on germination was promotive, but at +16°C, inhibitory and partly reversible by white light. It seems that Norway spruce seeds may have adapted to germinate in canopy shade light rich in far-red. The seeds may also have evolved mechanisms to inhibit germination in prolonged light.

  • Leinonen, ORCID ID:E-mail:
  • Rita, ORCID ID:E-mail:
article id 5504, category Article
Heli Peltola, Seppo Kellomäki. (1993). A mechanistic model for calculating windthrow and stem breakage of Scots pines at stand age. Silva Fennica vol. 27 no. 2 article id 5504. https://doi.org/10.14214/sf.a15665

A model for the mechanism of windfall and stem breakage was constructed for single Scots pine (Pinus sylvestris L.) at the stand edge. The total turning moment arising from the wind drag and from the bending of stem and crown was calculated along with the breaking stress of the stem. Similarly, the support given by the root -soil plate anchorage was calculated. Windspeed variation within the crown and the vertical distribution of stem and crown weight were taken into account. Model computations showed that trees having a large height to diameter ratio were subjected to greater risk of falling down or breaking than trees with a small height to diameter ratio. The windspeed required to blow down a tree or break the stem of a tree decreased if the height to diameter ratio or the crown to stem ratio of trees increased.
The PDF includes an abstract in Finnish.

  • Peltola, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5476, category Article
Jukka Selander, Auli Immonen. (1992). Effect of fertilization and watering of Scots pine seedlings on the feeding preference of the pine weevil (Hylobius abietis L.). Silva Fennica vol. 26 no. 2 article id 5476. https://doi.org/10.14214/sf.a15637

Two-year-old containerized Scots pine (Pinus sylvestris L.) seedlings, raised under different fertilization and watering regimes, were subjected to feeding preference tests with pine weevils (Hylobius abietis L.) in a bioassay. In the tests carried out with pairs of seedlings, the weevil preferred water-stressed seedlings to well-watered ones. In the case of well-watered seedlings, the weevil caused significantly more damage to NPK-fertilized seedlings than those given pure PK fertilization, or no fertilization at all. It is apparent that PK fertilization reduces, and water stress increases seedling susceptibility to weevil damage. The results support findings from field trials that water stress (planting shock) predisposes seedlings to weevil damage. Weevil resistance is discussed with respect to fertilization and water stress as determinants of seedling quality.

The PDF includes an abstract in Finnish.

  • Selander, ORCID ID:E-mail:
  • Immonen, ORCID ID:E-mail:
article id 5358, category Article
Lauri Kärenlampi, Andrew J. Friedland. (1988). Cytopathological and external observations on red spruce (Picea rubens Sarg.) needles damaged in winter in Vermont. Silva Fennica vol. 22 no. 3 article id 5358. https://doi.org/10.14214/sf.a15515

The red spruce (Picea rubens sarg.) population in the Green Mountains in Vermont has showed foliar deterioration that has not been fully explained. The most characteristic needle injuries of the sensitive trees appear in late winter when the first-year needles turn brown. The cytopathological and external observations on the symptoms support the interpretation that winter stress triggers the damage. It is possible that some anthropogenic stress factors (components of acid deposition or ozone) and/or natural factors predispose the trees to the damage.

The PDF includes an abstract in Finnish.

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

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

The PDF includes an abstract in Finnish.

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

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

The PDF includes a summary in Finnish.

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

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

The PDF includes a summary in Finnish.

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

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

  • Huttunen, ORCID ID:E-mail:
  • Kallio, ORCID ID:E-mail:
  • Karhu, ORCID ID:E-mail:
article id 5133, category Article
F. Scholz. (1981). Genecological aspects of air pollution effects on northern forests. Silva Fennica vol. 15 no. 4 article id 5133. https://doi.org/10.14214/sf.a15360

Natural forest tree populations are adapted to their natural environment. Forest tree species under northern conditions are at the edge of their range where the short growing season and the low winter temperatures are the two main factors limiting their ecological niche. Effects of air pollution on the ecological niche, designated as the environmental conditions that permit a population to survive permanently, are discussed according to G.E. Hutchinson’s concept of the ecological niche. Air pollution as an additional stress factor influences the ecological niche either by the direct influence as an additional dimension of the ecological niche or by interaction with the other dimensions. These interactions are especially important for low level long-term effects of air pollution which can result in reduced resistance to low winter temperature or, due to reduced net assimilation, reduced capability to survive the long period of winter dormancy. These effects influence the boundary of the ecological niche and reduce the area of the biotope of the respective species.

Within the remaining biotope genetic changes in forest tree species take place. Due to individual differences in exposure and susceptibility of trees to air pollution, higher and therefore more exposed trees as well as more susceptible trees will be reduced in reproduction or even be eliminated. This causes genetic changes in the tree population.

  • Scholz, ORCID ID:E-mail:
article id 4999, category Article
Tapio Klen, Veikko Louhevaara. (1978). Metsurin suojavarusteiden aiheuttama lisäkuormitus. Silva Fennica vol. 12 no. 3 article id 4999. https://doi.org/10.14214/sf.a14853
English title: The additional physical strain caused by safety equipment in logging work.

The safety clothing, rubber safety boots, belt with lifting hooks and personal protectors can weight about 3 kg more than the normal work clothing including rubber boots. In order to evaluate the increase off the physical strain in logging work due to them, laboratory tests performed on tread mill were made. The physical strain increased 3–11% as estimated from heart rate and 4–8% as estimated from oxygen consumption measurements.

The PDF includes a summary in English.

  • Klen, ORCID ID:E-mail:
  • Louhevaara, ORCID ID:E-mail:
article id 4985, category Article
Pertti Harstela. (1978). Metsätyön kuormittavuuden määrittelyä. Silva Fennica vol. 12 no. 1 article id 4985. https://doi.org/10.14214/sf.a14839
English title: Definition of the amount of strain caused by forest work.

The concepts central to ergonomic research connected with the amount of strain caused by work was studied. A model was made to describe the process of strain. The model includes the following concepts: load or stress, human input, worker, strain, renewal of human resources, output and their hierarchical units. Based on the quality of human input, the forest work was roughly divided into two categories: (1) work demanding primarily muscle activity and (2) neuro-sensory work. In the first group, especially in cutting work, the main part of the human input is intensive consumption of muscle energy. In addition, work load causes accidents, wear of skeletal and muscular systems and processes by noise, vibrations, and climate. Correspondingly, when operating forest machines, the human input is mainly neuro-sensory functions of the central nervous system. Work load causes directly the effects of low frequency vibration and of other work conditions. The model was tested on data from research of forest work.

The PDF includes a summary in English.

  • Harstela, ORCID ID:E-mail:
article id 4978, category Article
Paavo Valonen. (1977). Ajouraväli ja tekomiehen fyysinen kuormittuminen kuitupuun teossa. Silva Fennica vol. 11 no. 4 article id 4978. https://doi.org/10.14214/sf.a14832
English title: Strip road spacing and the physical strain put on forest workers during pulpwood cutting.

The physical strain put on forest workers and work time consumption during pulpwood cutting were compared when the bolts were stacked at the side of strip road, the strip road spacings being 15–25 m and 26–35 m, and when stacked at scattered points along the cutting strip.

When stacking at scattered points along cutting strip work time consumption was 17–21% and the heart rate 9–12% less than when stacking at the side of the strip road, strip road spacing being 15–25 m. When the strip road spacing was increased to 26–35 m, the time consumption increased by 18–30%, but the heart rate appeared unchanged. This result suggests that the forest worker compensates for increased physical strain caused by an increased stacking distance by changing his working technique and rate and by increasing the number of his breaks.

The PDF includes a summary in English.

  • Valonen, ORCID ID:E-mail:
article id 7653, category Article
Ladawan Atipanumpai. (1989). Acacia mangium : Studies on the genetic variation in ecological and physiological characteristics of a fastgrowing plantation tree species. Acta Forestalia Fennica no. 206 article id 7653. https://doi.org/10.14214/aff.7653

Genetic variation in the physiological characteristics and biomass accumulation of Acacia mangium Willd. was studied in both field and laboratory conditions. Variation in the growth characteristics, foliar nutrient concentration, phyllode anatomy and stomatal frequency was analysed in 16 different origins under field conditions in Central Thailand. Family variation and heritability of growth and flowering frequency were calculated using 20 open-pollinated families at the age of 28 months. The effect of environmental factors on diameter growth in different provenances is also discussed.

Under laboratory conditions, such physiological characteristics as transpiration rate, leaf conductance and leaf water potential were measured at varying soil moisture conditions. The responses of photosynthesis, photorespiration and dark respiration as well as the CO2 compensation point to temperature and irradiance were also investigated. All physiological characteristics indicated differences among provenances. An attempt was made to relate the results obtained in the laboratory to the growth performance in the field. Recommendations on provenance selection for the planting of A. mangium in Thailand are also given.

The PDF includes a summary in Finnish.

  • Atipanumpai, ORCID ID:E-mail:
article id 7596, category Article
Olavi Luukkanen. (1978). Investigations on factors affecting net photosynthesis in trees : gas exchanges in clones of Picea abies (L.) Karst. Acta Forestalia Fennica no. 162 article id 7596. https://doi.org/10.14214/aff.7596

The net photosynthetic rate per unit of foliage was studied in two-year old cuttings of Norway spruce (Picea abies (L.) H. Karst.), representing four clones, at varying temperature and soil moisture. The CO2 compensation point (Γ), photorespiration, dark respiration, and water balance were also investigated. All these characteristics indicated differences among the clones. A correlation between CO2 exchange and transpiration suggested that stomatal control determined at least a part of this variation during a favourable water balance. An inverse relationship existed between Γ and net photosynthetic rate, and the same curvilinear model explained this variation in unstressed as well as stressed plants at a given temperature. An increase in Γ seems to be a normal result of water stress, particularly at high temperature, indicating an increase in mesophyll resistance to CO2 diffusion. This result was in agreement with calculated values of mesophyll resistance. It also supported our earlier conclusions about the significance of mesophyll resistance during water stress.

  • Luukkanen, ORCID ID:E-mail:
article id 7595, category Article
Erkki Hallman, Pertti Hari, Pentti K. Räsänen, Heikki Smolander. (1978). Effect of planting shock on the transpiration, photosynthesis, and height increment of Scots pine seedlings. Acta Forestalia Fennica no. 161 article id 7595. https://doi.org/10.14214/aff.7595

In the experiment Scots pine (Pinus sylvestris L.) seedlings were transplanted out in the field. The effect of the treatments on gas metabolism and daily height increment were examined. The seedlings were 5-year old Scots pine plants growing in clay pots, covered with plastic bags. Transpiration and photosynthetic rates were monitored with open IRGA measuring system for a few days before being subjected to the treatments and for one month after. In addition, the daily amounts of transpired water and daily height increments were measured. A model for the potential rate of each metabolic process was constructed.

Planting and additional exposure had a strong and rather permanent effect on the self-regulation of the processes. This effect is very similar to that caused by water deficit. Exposure makes the disturbance more pronounced. Transpiration of the transplanted seedlings decreased in a few days after planting to less than half of the potential value and that of the exposed ones decreased to a quarter of the potential value. The daily amounts of photosynthesis decreased to half of the potential value. There was no recovery in photosynthesis during the whole monitoring period of four weeks. There was a slight recovery in transpiration about five weeks after transplanting.

Thus, the treatment probably generated stress conditions throughout the whole growing period, which is characterized by strong self-regulation of photosynthesis and transpiration, thus causing an essential decrease in the total amount of CO2 fixed. The photosynthesis was depressed especially at elevated temperatures after planting, as during water deficit. Planting and additional exposure did not produce any detectable changes in the dependence of the growth rate on temperature or in the effect of self-regulation on height growth. On the other hand, the level of growth was decreased as a result of planting out.

The PDF includes a summary in Finnish.

  • Hallman, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
  • Räsänen, ORCID ID:E-mail:
  • Smolander, ORCID ID:E-mail:
article id 7593, category Article
Erkki Wuolijoki. (1977). Metsätyöntekijän väsyminen. Acta Forestalia Fennica no. 159 article id 7593. https://doi.org/10.14214/aff.7593
English title: Fatigue in forest work.

The aim of the study was to search for measurement methods of muscle fatigue in forest work. Lactic acid concentration of capillary blood was measured from test persons after submaximal and maximal strain tests in laboratory and during forest work. At rest the lactic acid content was affected mainly by the body dimensions and blood pressure. In a maximal strain test it was affected mainly by the age. In submaximal forest work lactic acid content concentrated below the attitude factor indicating working pace and below the body dimensions so that bigger persons had a higher lactic acid concentration than smaller persons.

The PDF includes a summary in English.

  • Wuolijoki, ORCID ID:E-mail:

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