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Silva Fennica vol. 43 no. 2 | 2009

Category: Research article

article id 213, category Research article
Bum-Jin Park, Yuko Tsunetsugu, Tamami Kasetani, Takeshi Morikawa, Takahide Kagawa & Yoshifumi Miyazaki. (2009). Physiological effects of forest recreation in a young conifer forest in Hinokage Town, Japan. Silva Fennica vol. 43 no. 2 article id 213. https://doi.org/10.14214/sf.213
It is widely believed that coming into contact with forest environments is somehow beneficial to human well-being and comfort. In Japan, “Shinrin-yoku” (taking in the atmosphere of a forest) has been proposed to be a relaxation activity associated with forest recreation. The purpose of this study was to examine the physiological effects of forest recreation on the autonomic nervous activity. The subjects were twelve male university students (21.8 ± 0.8 years old). On the first day of the experiment, six subjects were sent to a forest area, and the other six to a city area. On the second day, each subject was sent to the area he did not visit on the first day as a cross check. The subjects walked (15 minutes) around their assigned areas before noon, and sat on chairs viewing (15 minutes) the landscapes of their assigned areas in the afternoon. Heart rate variability (HRV), blood pressure, and pulse rate were measured as physiological indices. Measurements were taken at the place of accommodation in the morning, before and after walking, and before and after viewing at their assigned field areas. Pulse rate, diastolic blood pressure and LF/(LF+HF) (LF – low frequency, HF – high frequency) components of HRV were significantly lower in the forest area than in the city area. HF components of HRV tended to be higher in the forest than in the city. In conclusion, the results of the physiological measurements show that forest recreation enabled effective relaxation in people, both of the mind and body.
  • Park, Chiba University, Center for Environment, Health and Field Sciences, Kashiwa-no-ha 6-2-1, 277-0882 Kashiwa, Chiba, Japan ORCID ID:E-mail: bjpark@faculty.chiba-u.jp (email)
  • Tsunetsugu, Chiba University, Center for Environment, Health and Field Sciences, Kashiwa-no-ha 6-2-1, 277-0882 Kashiwa, Chiba, Japan ORCID ID:E-mail:
  • Kasetani, Chiba University, Center for Environment, Health and Field Sciences, Kashiwa-no-ha 6-2-1, 277-0882 Kashiwa, Chiba, Japan ORCID ID:E-mail:
  • Morikawa, Chiba University, Center for Environment, Health and Field Sciences, Kashiwa-no-ha 6-2-1, 277-0882 Kashiwa, Chiba, Japan ORCID ID:E-mail:
  • Kagawa, Chiba University, Center for Environment, Health and Field Sciences, Kashiwa-no-ha 6-2-1, 277-0882 Kashiwa, Chiba, Japan ORCID ID:E-mail:
  • Miyazaki, Chiba University, Center for Environment, Health and Field Sciences, Kashiwa-no-ha 6-2-1, 277-0882 Kashiwa, Chiba, Japan 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 211, category Research article
Timo Pukkala. (2009). Population-based methods in the optimization of stand management. Silva Fennica vol. 43 no. 2 article id 211. https://doi.org/10.14214/sf.211
In Finland, the growth and yield models for tree stands are simulation programs that consist of several sub-models. These models are often non-smooth and non-differentiable. Direct search methods such as the Hooke-Jeeves algorithm (HJ) are suitable tools for optimizing stand management with this kind of complicated models. This study tested a new class of direct search methods, namely population-based methods, in the optimization of stand management. The tested methods were differential evolution, particle swarm optimization, evolution strategy, and the Nelder-Mead method. All these methods operate with a population of solution vectors, which are recombined and mutated to obtain new candidate solutions. The management schedule of 719 stands was optimized with all population-based methods and with the HJ method. The population-based methods were competitive with the HJ method, producing 0.57% to 1.74% higher mean objective function values than HJ. On the average, differential evolution was the best method, followed by particle swarm optimization, evolution strategy, and Nelder-Mead method. However, differences between the methods were small, and each method was the best in several stands. HJ was alone the best method in 7% of stands, and a population based method in 3% (Nelder-Mead) to 29% (differential evolution) of stands. All five methods found the same solution in 18% of stands.
  • Pukkala, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: timo.pukkala@joensuu.fi (email)
article id 210, category Research article
Juha Heiskanen, Markku Lahti, Jaana Luoranen & Risto Rikala. (2009). Nutrient loading has a transitory effect on the nitrogen status and growth of outplanted Norway spruce seedlings. Silva Fennica vol. 43 no. 2 article id 210. https://doi.org/10.14214/sf.210
In recent years increased fertilization provided to tree seedlings in the nursery in the previous autumn has been introduced in order to promote good outplanting performance. In this paper this nutrient loading has been studied in order to determine how the increased seedling nutrient status with unaffected seedling size affects both the growth and the nutrient concentration, content and uptake of two-year-old Norway spruce container seedlings (Picea abies (L.) Karsten) after outplanting. Seedling development was monitored for three years at two contrasting soil fertility levels on a sandy test field in two planting years and on one natural forest outplanting site in central Finland. Nutrient loading was shown to increase shoot and root growth in a poor fertility soil during the first growing season after planting, while, after the first growing season, nutrient loading was not found to affect seedling performance. However, although nutrient loading cannot compensate for the availability of nutrients to the seedlings from the soil, it may provide an additional input for fast plantation establishment on poorer sites during the first crucial growing season after outplanting.
  • Heiskanen, The Finnish Forest Research Institute, Suonenjoki Research Unit, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: juha.heiskanen@metla.fi (email)
  • Lahti, The Finnish Forest Research Institute, Suonenjoki Research Unit, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Luoranen, The Finnish Forest Research Institute, Suonenjoki Research Unit, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Rikala, The Finnish Forest Research Institute, Suonenjoki Research Unit, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 209, category Research article
Jaana Luoranen, Kyösti Konttinen & Risto Rikala. (2009). Frost hardening and risk of a second flush in Norway spruce seedlings after an early-season short-day treatment. Silva Fennica vol. 43 no. 2 article id 209. https://doi.org/10.14214/sf.209
There have been years in Finland when container seedlings of Norway spruce (Picea abies (L.) Karsten) planted in the summer have been damaged by early-autumn frosts. For August and September plantings, the seedlings can be hardened by means of short-day (SD) treatment, but little information is available about its usability for earlier plantings. We studied the effects of early-season SD treatment on the frost hardiness and risk of a second flush of Norway spruce seedlings. In three successive years, second-year seedlings were grown in a greenhouse or outdoors in the spring and early summer and then subjected to two or three-week SD treatment beginning on the second, third, or fourth week of June. We monitored the height growth cessation, bud formation, and frost hardiness of the seedlings in the nursery. All SD treatments made the height growth cease, but the risk of a second flush increased if the temperature sum was less than 300 d.d. before the beginning of the SD treatment or more than 450 d.d. between the end of the treatment and mid-August. Clearly, then, SD treatment reduced the risk of a second flush in seedlings that had been grown in a greenhouse in the spring. Early-season SD treatment increased the frost hardiness of both needles and stems for late July to early September in comparison with untreated seedlings. Later in the autumn, however, the differences disappeared. Before recommending the use of early-season SD-treated seedlings for summer planting, the method has to be tested in practical field conditions.
  • Luoranen, The Finnish Forest Research Institute, Suonenjoki Research Unit, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@metla.fi (email)
  • Konttinen, The Finnish Forest Research Institute, Suonenjoki Research Unit, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Rikala, The Finnish Forest Research Institute, Suonenjoki Research Unit, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 208, category Research article
Mikko Räisänen, Tapani Repo & Tarja Lehto. (2009). Cold acclimation of Norway spruce roots and shoots after boron fertilization. Silva Fennica vol. 43 no. 2 article id 208. https://doi.org/10.14214/sf.208
Boron deficiency, manifested as shoot dieback, is a problem in conifer stands growing on soils with high nitrogen availability in Fennoscandia. Earlier observations on Norway spruce (Picea abies L. Karst.) suggest that freezing tolerance is decreased by boron deficiency. Here, the effect of boron fertilization on cold acclimation of Norway spruce was studied in a young stand with initially low boron status two years after fertilization. Buds, stems, needles and roots were collected at five sampling times during cold acclimation and subsequently exposed to series of freezing temperatures. Lethal temperatures of organs were assessed by electrolyte leakage method (EL) and visual scoring of damage (VS). Freezing tolerance of buds was measured also by differential thermal analysis (DTA). The mean boron (B) concentration in needles was 4 mg kg–1 in unfertilized and 21 mg kg–1 in B-fertilized trees while critical level of B deficiency is considered to be 5 mg kg–1. The risk for increased freezing injuries in the low-B trees was not evident since all trees achieved cold hardiness that would be sufficient in central Finland. At two sampling times out of five, shoots or stem of B-fertilized trees were slightly more freezing tolerant than non-fertilized trees. However, the present study does not give strong evidence for the hypothesis that decreased freezing tolerance in B deficiency would be a triggering factor for leader dieback in Norway spruce at the B levels studied.
  • Räisänen, University of Joensuu, Faculty of Forest Sciences, P.O.Box 111, FI-80101 Joensuu, Finland; (present address), FAForest, FI-83480 Ahonkylä, Finland ORCID ID:E-mail:
  • Repo, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Lehto, University of Joensuu, Faculty of Forest Sciences, P.O.Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: tarja.lehto@joensuu.fi
article id 207, category Research article
Mats T. Olsson, Maria Erlandsson, Lars Lundin, Torbjörn Nilsson, Åke Nilsson & Johan Stendahl. (2009). Organic carbon stocks in Swedish Podzol soils in relation to soil hydrology and other site characteristics. Silva Fennica vol. 43 no. 2 article id 207. https://doi.org/10.14214/sf.207
Site characteristics influence soil organic carbon (SOC) stocks. In Podzols under Swedish forest land, SOC stocks were related to latitude, altitude, soil hydrological class categorized by mean groundwater level, mean annual precipitation, temperature sum during the growing season, total annual nitrogen (N) deposition and site capacity. SOC stocks were determined for the O-horizon and for total soil (O-horizon + mineral soil to a depth of 50 cm). Data from the Swedish National Forest Soil Inventory 1993–2001 were used (1477 field plots). The O-horizon was sampled with a core sampler and carbon (C) stocks were determined. For the mineral soil layers the SOC stock was calculated based on the SOC concentrations, bulk density and content of rock fragments. The results showed that the overall mean SOC stock was 2.8 and 8.2 kg C m–2 for O-horizon and total soil, respectively. Soil hydrological class strongly affected SOC stocks, which increased from on average 6.7 kg C m–2 at dry sites to 9.7 kg C m–2 at slightly moist sites. Corresponding values for the O-horizon were 2.0 to 4.4 kg C m–2. The correlation coefficients for the linear relationship between SOC stock and site characteristics were highest for N deposition, which explained up to 25% of variation, and latitude, which explained up to 20% of variation. Altitude had the lowest degree of explanation.
  • Olsson, Swedish University of Agricultural Sciences, Dept of Soil and Environment, Uppsala, Sweden ORCID ID:E-mail:
  • Erlandsson, Swedish University of Agricultural Sciences, Dept of Soil and Environment, Uppsala, Sweden ORCID ID:E-mail:
  • Lundin, Swedish University of Agricultural Sciences, Dept of Soil and Environment, Uppsala, Sweden ORCID ID:E-mail:
  • Nilsson, Swedish University of Agricultural Sciences, Dept of Soil and Environment, Uppsala, Sweden ORCID ID:E-mail: torbjorn.nilsson@mark.slu.se (email)
  • Nilsson, Swedish University of Agricultural Sciences, Dept of Soil and Environment, Uppsala, Sweden ORCID ID:E-mail:
  • Stendahl, Swedish University of Agricultural Sciences, Dept of Soil and Environment, Uppsala, Sweden ORCID ID:E-mail:
article id 206, category Research article
Qiaoying Zhang, Yunchun Zhang, Shaolin Peng, Eshetu Yirdaw & Ning Wu. (2009). Spatial structure of alpine trees in Mountain Baima Xueshan on the southeast Tibetan Plateau. Silva Fennica vol. 43 no. 2 article id 206. https://doi.org/10.14214/sf.206
Most of the trees at treeline on the Tibetan Plateau are endemic to the Plateau. Yet little is known about these species. The study focused on the population structure, spatial patterns and associations of the treeline species Abies forestii var. georgei and Juniperus saltuaria at treeline and timberline in Mountain Baima Xueshan on the southeast Tibetan Plateau. These species form monodominant communities on the north- and south-facing slopes, respectively. Stem density, DBH-distribution, distribution pattern of different tree size classes, and intraspecific spatial association between different tree size classes of both species were analyzed. Spatial structure varied between A. forestii var. georgei and J. saltuaria, and for the same species, the spatial structures were also different from timberline to treeline. Stem density, mean tree height and young individuals of A. forestii var. georgei were significantly higher than those of J. saltuaria. For the same species, they were different from timberline to treeline, i.e., stem density and mean tree height of both species became lower. Size classes of both species were mainly clustered either at treeline or at timberline but at different scales, and spatial patterns of young J. saltuaria were mainly dominated by random patterns. Clumps of trees created more favorable microenvironments in harsh environments at treeline and timberline. Most tree size classes showed positive intraspecific spatial associations, but positive associations between size classes of J. saltuaria were not as significant as those of A. forestii var. georgei. The south-facing slope was usually subjected to varying intensities of pastoralism. Livestock disturbance greatly changed the microhabitat and reduced the number of young individuals. The potential of trees to regenerate was greatly inhibited, while A. forestii var. georgei showed greater regeneration potential. Spatial structures of J. saltuaria were also modified by this kind of human impact.
  • Zhang, State Key Laboratory of Biocontrol, Sun Yat-Sen University, Guangzhou 510275, Guangdong Province, China; Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, Sichuan Province, China ORCID ID:E-mail: lsspsl@mail.sysu.edu.cn (email)
  • Zhang, Shandong Institute of Light Industry, Jinan 250353, Shandong Province, China ORCID ID:E-mail:
  • Peng, State Key Laboratory of Biocontrol, Sun Yat-Sen University, Guangzhou 510275, Guangdong Province, China ORCID ID:E-mail:
  • Yirdaw, Viikki Tropical Resources Institute (VITRI), P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Wu, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, Sichuan Province, China ORCID ID:E-mail:
article id 205, category Research article
Pekka Vakkari, Mari Rusanen & Katri Kärkkäinen. (2009). High genetic differentiation in marginal populations of European white elm (Ulmus laevis). Silva Fennica vol. 43 no. 2 article id 205. https://doi.org/10.14214/sf.205
Studies on the amount of genetic variation in marginal populations and differentiation between them are essential for assessment of best gene conservation strategies and sampling schemes. Thirteen marginal populations of Ulmus laevis in southern Finland and one in Estonia were investigated for genetic variation in 20 allozyme loci. Population differentiation among Finnish stands was high, Fst = 0.290, and mean genetic diversity low, He = 0.088. The differentiation follows the isolation-by-distance structure within the core of the distribution area (lake Vanajavesi). Fairly high frequency of recurrent genotypes was observed, but this did not have an influence on the genetic parameters. The observed genetic structure is consistent with the central-marginal hypothesis. In the light of the results, the Finnish gene conservation strategy for U. laevis seems to be on a sound basis.
  • Vakkari, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: pekka.vakkari@metla.fi (email)
  • Rusanen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Kärkkäinen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:

Category: Review article

article id 463, category Review article
Thomas Gschwantner, Klemens Schadauer, Claude Vidal, Adrian Lanz, Erkki Tomppo, Lucio di Cosmo, Nicolas Robert, Daisy Englert Duursma & Mark Lawrence. (2009). Common tree definitions for national forest inventories in Europe. Silva Fennica vol. 43 no. 2 article id 463. https://doi.org/10.14214/sf.463
At the international level, various definitions have been established for the compilation and publication of forest resources assessment results over the last decade. These international definitions frequently rely on terms that are not precisely specified for inventory purposes and do not completely cover the requirements arising from the application of National Forest Inventory (NFI) data. Also, with respect to conventional topics such as forest area and growing stock estimation, several terms and expressions referring to individual trees are not, or are only vaguely, defined until now. Since the individual tree is the basic element of any forest resources assessment, the clarification of tree-related terms is an important part of COST Action E43 to harmonise common reporting of National Forest Inventories. Based on a review of existing definitions and on the requirements for harmonised reporting, common tree-related definitions are established. One objective of this study is to refine and enhance the applicability of available tree and shrub definitions, in particular with regard to the distinction between trees and shrubs. The study also focuses on the parts or “elements” of trees and on the distinction between these elements as they are of particular importance in growing stock and biomass definitions. Furthermore, several definitions for tree characteristics such as “living” and “standing”, as well as tree variables such as height, length, diameter at breast height, and crown projection area are adjusted with respect to NFI purposes. A concluding discussion reflects upon the reviewed, refined and newly established definitions. The definitions presented in this paper provide a firm basis for a common set of harmonised reference definitions developed by COST Action E43 and contribute to the precise and consistent use of terms.
  • Gschwantner, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Wien, Austria ORCID ID:E-mail: thomas.gschwantner@bfw.gv.at (email)
  • Schadauer, Federal Research and Training Centre for Forests, Natural Hazards and Landscape, Wien, Austria ORCID ID:E-mail:
  • Vidal, French National Forest Inventory, Nogent-sur-Vernisson, France ORCID ID:E-mail:
  • Lanz, Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf, Switzerland ORCID ID:E-mail:
  • Tomppo, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • di Cosmo, Agricultural Research Council – Forest Monitoring and Planning Research Unit, Trento, Italy ORCID ID:E-mail:
  • Robert, French National Forest Inventory, Nogent-sur-Vernisson, France ORCID ID:E-mail:
  • Englert Duursma, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • Lawrence, Northern Research Station, Roslin, Midlothian, Great Britain ORCID ID:E-mail:

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