Showing papers in "Journal of forest science in 2018"
TL;DR: Forest classification, made up by Plíva and Průša (Plíva 1971), has been used in the Czech Republic forestry since 1970 as mentioned in this paper, based on ecological factors of the environment.
Abstract: Forest classification, made up by Plíva and Průša (Plíva 1971), has been using in the Czech Republic forestry since 1970. This classification is based on ecological factors of the environment. Edaphic conditions are at the first position, then climatic conditions follow (by their vertical [altitudinal] distribution mainly). These two factors form the basic construction called ecological grid (Table 1).
97 citations
TL;DR: The formation, size distribution and percentage of gaps in two virgin deciduous forests are presented in two case studies as discussed by the authors, and the largest gap in Havesova Reserve was 0.40 ha, resulting from the death of 56 trees over the last 40 years.
Abstract: The formation, size distribution and percentage of gaps in two virgin deciduous forests are presented in two case studies. Gaps are defined as openings in the canopy above 2/3 of stand height. These gaps comprise 16% of the forest area in Havesova Reserve and 14.6% of the forest area in Kyjov Reserve. The estimated turnover time is 220 years. More than half the gaps were caused by the death of one tree, and 80% of the gaps were due to the death of up to 3 trees. The largest gap in Havesova Reserve was 0.40 ha, resulting from the death of 56 trees over the last 40 years. The area of the largest gap in Kyjov Reserve was 0.44 ha. It was caused by the death of 80 trees over the last 40 years. Such large gaps are scarce. 85% of the gaps are smaller than 250 m². A correction of the bias towards the over-abun- dance of large gaps by line-transect sampling was made by estimating the percentage area of gaps of different size from the percentage length along the transects. In Havesova an attempt was made to date the death of trees that were still visible in the gaps. 1/5 of the trees initiated gaps by their death, while 4/5 of the trees extended gaps. While uprooted trees dominate in Havesova, breakage is most common in Kyjov.
80 citations
TL;DR: In this paper, the application of hydrogel granules is simple but it is very complicated not to cause the overdosage because of the very high swelling capacity of Hydrogel.
Abstract: In this study results of hydrogel application in reclamations are presented. The application of hydrogel af - fected the survival of pine seedlings during two vegetation periods after planting. Double application of STOCKOSORB AGRO (gel) on the root system after lifting caused an about 19% higher survival rate compared to control variants. The application of 7 g/planting hole of STOCKOSORB MICRO granules caused overdosage and plant mortality. The application of hydrogel granules is simple but it is very complicated not to cause the overdosage because of the very high swelling capacity of hydrogel. Research should be carried out to determine suitable hydrogel application rates for different environmental conditions and tree species. To design a technology with regard to the economic effectiveness of application will be a very important task.
77 citations
TL;DR: The objective of study was to develop a method using GIS and Multi-criteria Evaluation (MCE) to design a forest road network with the lowest construction cost while maintaining other technical requirements.
Abstract: One of the cost factors in forest management is the development of road infrastructure. The objective of study was to develop a method using GIS and Multi-criteria Evaluation (MCE) to design a forest road network with the lowest construction cost while maintaining other technical requirements. Six road alternatives meeting technical requirements were developed using PEGGER. Then MCE was used to evaluate the construction costs of the candidate networks. The decision making group identified six factors as being relevant to the costs of forest roads. Then factors were compared in a pair-wise comparison, in the context of the Analytic Hierarchy Process to develop weights of map layers. Then weights and factors were entered into the MCE module to create a final suitability map. The total cost of each alternative was extracted from the suitability map and the unit cost of each alternative was calculated. The results showed that alternatives one and two had the highest and lowest unit costs, respectively. The results illustrated the utility of using GIS and MCE to improve the planning process.
69 citations
TL;DR: In this article, the acidification and depletion of nutrient cations have been reported for several forested regions in North America, predominantly in the eastern United States, including the northeast and in the central Appalachians, but also in parts of southeastern Canada and the southern U.S.
Abstract: Forest soil acidification and depletion of nutrient cations have been reported for several forested regions in North America, predominantly in the eastern United States, including the northeast and in the central Appalachians, but also in parts of southeastern Canada and the southern U.S. Continuing regional inputs of nitrogen and sulfur are of concern because of leaching of base cations, increased availability of soil Al, and the accumulation and ultimate transmission of acidity from forest soils to streams. Losses of calcium from forest soils and forested watersheds have now been documented as a sensitive early indicator and a functionally significant response to acid deposition for a wide range of forest soils in North America. For red spruce, a clear link has been established between acidic deposition, alterations in calcium and aluminum supplies and increased sensitivity to winter injury. Cation depletion appears to contribute to sugar maple decline on some soils, specifically the high mortality rates observed in northern Pennsylvania over the last decade. While responses to liming have not been systematically examined in North America, in a study in Pennsylvania, restoring basic cations through liming increased basal area growth of sugar maple and levels of calcium and magnesium in soil and foliage. In the San Bernardino Mountains in southern California near the west coast, the pH of the A horizon has declined by at least 2 pH units (to pH 4.0-4.3) over the past 30 years, with no detrimental effects on bole growth; presumably, because of the Mediterranean climate, base cation pools are still high and not limiting for plant growth.
69 citations
TL;DR: In this article, a study of labour productivity was conducted in fully mechanized harvesting technologies, and the productivity of harvesters was particularly affected by the average tree volume of the felled trees.
Abstract: A study of labour productivity was conducted in fully mechanised harvesting technologies. The study revealed that the productivity of harvesters was particularly affected by the average tree volume of the felled trees, and the productivity of forwarders was affected mainly by two factors – haulage distance and machine payload. Dependences of other factors such as natural and site conditions, technical parameters and skills of operators could not be demonstrated. Regression equations of dependences were created for all these three significant criteria and costs per cubic meter of processed timber were calculated for them according to the cost function. A regression function was then developed for the forwarder that takes into account both significant criteria influencing the forwarder productivity.
64 citations
TL;DR: In this article, the Weibull distribution was used to fit tree diameter data collected from 86 sample plots located in Chinese pine stand in Beijing and three methods (namely maximum likelihood estimation method (MLE), method of moment (MOM) and least-squares regression method (LSM)) were compared and evaluated on the basis of the mean square error (MSE) and sample size.
Abstract: Weibull distribution was used to fit tree diameter data collected from 86 sample plots located in Chinese pine stand in Beijing. To estimate the Weibull distribution parameters, three methods (namely maximum likelihood estimation method (MLE), method of moment (MOM) and least-squares regression method (LSM)) were compared and evaluated on the basis of the mean square error (MSE) and sample size. For these sample plots, the moment method was superior for estimating the parameters of Weibull distribution for tree diameter distribution.
57 citations
TL;DR: In this paper, the authors aimed to estimate above-and below-ground carbon stock in Tankawati natural hill forest of Bangladesh, where a systematic sampling method was used to identify each sampling point through Global Poa-sitioning System (GPS).
Abstract: : The research was aimed to estimate above- and below-ground carbon stock in Tankawati natural hill forest of Bangladesh. systematic sampling method was used to identify each sampling point through Global Poa -sitioning System (GPS). Loss on ignition and wet oxidation method were used to estimate biomass and soil carbon stock, respectively. Results revealed that the total carbon stock of the forest was 283.80 t·ha −1 whereas trees produce 110.94 t·ha −1 , undergrowth (shrubs, herbs and grass) 0.50 t·ha −1 , litter fall 4.21 t·ha −1 and soil 168.15 t·ha −1 (up to 1m depth). The forest in the study area is a reservoir of carbon, as it has a good capacity to stock carbon from the atmos -phere. To realize the forest sector potentiality in Bangladesh, the carbon sequestration should be integrated with the Clean Development Mechanism (CDM) carbon trading system of the Kyoto Protocol. Keywords : Tankawati natural hill forest; carbon stock; geo-position Abbreviation : Sl. No. − serial number; TaGB, TBGB − total above- and below-ground biomass; TB − total biomass; TaGC, TBGC − total above- and below-ground carbon; TC − total carbon; TBC − total biomass carbon; LBC − litter fall biomass carbon; SOC − soil organic carbon.Supported by the United States Department of agriculture (USDa), Project No. BG-aRS-124.
52 citations
TL;DR: In this paper, the authors dealt with the natural abundance of 15 N and 13 C in the soil and needles of the pine forest (Pinus roxburghii, Sargent) along an altitudinal gradient and found that the higher altitude soil was much more depleted of 13 C than the lower altitude soil.
Abstract: This paper deals with natural abundance of 15 N and 13 C in the soil and needles of the pine forest (Pinus roxburghii, Sargent) along an altitudinal gradient The study area lies in the elevation range of 1,200 m to 2,200 m in Kathmandu valley of Nepal The higher altitude soil was found to be much more depleted of 13 C than the lower altitude soil The decreasing trend of C-isotope (as well as the trend of N-isotope) might be attributed to the lower mineralisation rate and net nitrification rate at the higher altitude The observed differences in isotopic N- and C-contents of needles and soils across altitudinal gradients in this study are a result of the combination of environmentally induced variations in physiological and morphological differences For example, altitudinal variation in needle δ 15 N and δ 13 C at the research site indicates that the needle isotopic composition is related to nitrogen availability at a site
52 citations
TL;DR: In this paper, the authors identify and test a complex index (S-index) allowing to take into account both the tree species composition and the stand structure, which can be combined in a composite index in order to evaluate the complex diversity at the stand level.
Abstract: Stand structure and species diversity are two useful parameters to provide a synthetic measure of forest biodiversity. The stand structure is spatial distribution, mutual position, diameter and height differentiation of trees in a forest ecosystem and it highly influences habitat and species diversity. The forest stand and species diversity can be measured through indices that provide important information to better address silvicultural practices and forest management strategies in the short and long-term period. These indices can be combined in a composite index in order to evaluate the complex diversity at the stand level. The aim of the paper is to identify and to test a complex index (S-index) allowing to take into account both the tree species composition and the stand structure. S-index was applied in a case study in the north-east of Italy (Trentino province). The results show that the Norway spruce forests in Trentino province are characterized by a medium-low level of complexity ( S-index is in a range between 0.14 and 0.46) due to a low tree species composition rather than to the stand structure (diametric differentiation and spatial distribution of trees).
51 citations
TL;DR: In this article, the authors describe parameterization of allometric functions applicable to biomass estimation of European beech trees based on field data from destructive measurements of 20 full-grown trees with diameter at breast height from 5.7 to 62.1 cm.
Abstract: This material describes parameterization of allometric functions applicable to biomass estimation of European beech trees. It is based on field data from destructive measurements of 20 full-grown trees with diameter at breast height (dbh) from 5.7 to 62.1 cm. The parameterization was performed for total tree aboveground biomass ( AB; besides stump), stem and branch biomass, respectively. The allometric functions contained two or three parameters and used dbh either as a single independent variable or in combination with tree height (H). These functions explained 97 to 99% of the variability in the measured AB. The most successful equation was that using both dbh and H as in- dependent variables in combination with three fitted parameters. H, as the second independent variable, had rather a small effect on improving the estimation: in the case of AB, H as independent variable improved prediction accuracy by 1-2% whereas in the case of branch biomass by about 5%. The parameterized biomass equations are applicable to tree specimens of European beech grown in typically managed forests.
TL;DR: In this paper, the effects of ground-based skidding on site disturbance and soil physical properties were assessed, showing that dry bulk density, total porosity and moisture content were affected considerably on skid trails by traffic frequency and skid trail slope.
Abstract: Soil properties can be affected by heavy equipment used for skidding but these impacts vary greatly with site conditions and operational practices. We assessed the effects of ground-based skidding on site disturbance and soil physical properties. We also tested the effects of skid trail slope and traffic frequency on soil compaction, total porosity, and moisture content. On average, about 30% of all harvested area was disturbed to varying levels. In - tact forest floor (undisturbed) and light slash were the dominant surface conditions, covering an average of 68.9% of harvested area. Deep disturbed soils accounted for only just over 1.1% of observations. Results showed that dry bulk density, total porosity and moisture content were affected considerably on skid trails by traffic frequency and skid trail slope. Measurements of soil properties in the surface layer (0-10 cm) showed that bulk density is 57% higher and total porosity is 31% lower on the skid trail compared to the undisturbed area. Average moisture content has been measured as 35% on the skid trail versus 47% in the undisturbed area.
TL;DR: In this article, the authors describe the parameterization of biomass functions applicable to oak (Quercus robur, Quer- cus petraea) trees grown in the conditions of Central-European forestry.
Abstract: This study describes the parameterization of biomass functions applicable to oak ( Quercus robur, Quer- cus petraea) trees grown in the conditions of Central-European forestry. It is based on destructive measurements of 51 grown trees sampled from 6 sites in different regions of the Czech Republic important for oak forest management. The samples covered trees of breast height diameter ( D) ranging from 6 to 59 cm, tree height ( H) from 6 to 32 m and age between 12 and 152 years. The parameterization was performed for total aboveground biomass and its individual components. The two basic levels of biomass functions utilized either as a single independent variable or in combina - tion with H. The functions of the third level represented the best function for each biomass component with the optimal combination of available independent variables, which included D, H, crown length ( CL), crown width ( CW), crown ratio (CR = CL/H), tree age and site altitude. D was found to be a particularly strong predictor for total tree aboveground biomass. H was found to always improve the fit, particularly for the individual components of aboveground biomass. The contribution of CW was minor, but significant for all biomass components, whereas CL and CR were found useful for the components of stem and living branches, respectively. Finally, the remaining variables tree age and altitude were each justified only for one component function, namely living branch biomass and stem bark, respectively. The study also compares the fitted functions with other available references applicable to oak trees.
TL;DR: In this paper, the authors consider the multiple demands on forests in a rapidly evolving economic, social, and political environment require maintaining a high level of forest management standards and a flexible adaptation of multiple-use forestry to the complex interactions between the private and public sectors.
Abstract: The present distribution of forests and the degree of their transformation by man are the results of natural factors and cultural development. The limit between forested areas and open spaces, as well as differences between intensively used forests and those showing small or no traces of human intervention, is determined by social needs and values, economic opportunities, and political regulations. Forests are currently perceived by the population as physical and social spaces profoundly influenced by timber use and forest management. Their social and political significance is in full evolution. The multiple demands on forests in a rapidly evolving economic, social, and political environment require maintaining a high level of forest management standards and a flexible adaptation of multiple-use forestry to the complex interactions between the private and public sectors.
TL;DR: In this article, a study was carried out in a steep and difficult terrain, where trees were logged downhill to the landing by a wheeled skidder Timberjack 450C, with an average slope of 30%.
Abstract: This study was carried out in a steep and difficult terrain. Trees were logged downhill to the landing by a wheeled skidder Timberjack 450C. Selection cutting was performed on a 66-hectare tract with an average slope of 30%. The elemental time study method was applied to develop the skidding time predicting model. In this study 43 working cycles were included. The skidding cycle time was mainly affected by skidding distance, winching distance and interac - tion between skidding distance and slope. The gross and net production rate was 20.51 and 22.93 m 3 /h, respectively. The unit cost considering the gross and net production rate was 6.31 and 6.22 USD/m 3 , respectively.
TL;DR: In this paper, Nothofagus pumilio and N an- tarctica seedlings were measured at different photosynthetic photon flux densities (PPFDs, 20, 150, 250, 500, 750, 1,000, 1.500, and 2,200 µmol/m 2 /s) and after 60 minutes of shade to determine the rate of photosynthesis induction after seed - ling transition from low to high PPFD A and gs were also measured to evaluate the responses to water stress and the tolerance to waterlogging N pum
Abstract: Net photosynthetic rate ( A) and stomatal conductance ( gs) of leaves of Nothofagus pumilio and N an- tarctica seedlings were measured at different photosynthetic photon flux densities (PPFDs, 20, 150, 250, 500, 750, 1,000, 1,500 and 2,200 µmol/m 2 /s) and after 60 minutes of shade to determine the rate of photosynthetic induction after seed - ling transition from low to high PPFD A and gs were also measured to evaluate the responses to water stress and the tolerance to waterlogging N pumilio had higher A values than N antarctica for all light intensities measured with the maximum value of 168 µmol CO 2 /m 2 /s saturated at 1,000 µmol/m 2 /s PPFD Values of gs for both Nothofagus species also declined as light intensity decreased The times required for full induction of
TL;DR: In this paper, the authors assess terrestrial ecosystem development (mainly vegetation and soil charac - teristics) in the area of a sand mine cast (located in southern Poland) that has been either reclaimed or left for natural succession.
Abstract: The aim of the study was to assess terrestrial ecosystem development (mainly vegetation and soil charac - teristics) in the area of a sand mine cast (located in southern Poland) that has been either reclaimed or left for natural succession. A total of 20 sites in a chronosequence of 5, 17, 20 and 25 years were set up in two site categories: reclaimed and non-reclaimed sites. Selected properties of initial soils and features of vegetation were measured and they included carbon accumulation in soil; biomass and diversity of communities were also estimated. Next, based on carbon accumula - tion, the energy trapped in ecosystem components was estimated. Although the results of plant community investigation did not show the same distinct differences between site categories, the case study suggests that reclamation significantly accelerates ecosystem development. In comparison with spontaneous succession, the complete forest reclamation was found to increase the amount of carbon accumulation, thickness of humus horizon, and energy trapped in soil organic carbon and plant biomass in the developing ecosystem 2-3 times and nitrogen accumulation 5 times.
TL;DR: It was necessary to collect the most frequent names used in the past and to assort them in a tabular manner into a convenient synoptic schedule respecting the present concepts of the complex - and assign them with the present most commonly used names.
Abstract: The Pinus mugo complex ( P. mugo Turra sensu lato, and/or species aggregate or group - P. mugo agg., including its internal as well as external aggregate hybrids) is an important fragment of European dendroflora. For its high variability this complicated group has not been solved in taxonomical terms satisfactorily yet. Most problems are mainly caused by a large amount of taxa of uncertain value described in the past, which often more or less overlap or are based on insufficiently researched and unsuitably interpreted characters. Such facts coincidently cause further problems in applied disciplines. Specialized European literature already contains a large amount of information referring to individual taxa of this complex. Much information is listed under various, often commonly not known or not used scientific names. In order to make the information available and useful, it was necessary to collect the most frequent names used in the past and to assort them in a tabular manner into a convenient synoptic schedule respecting the present concepts of the complex - and assign them with the present most commonly used names.
TL;DR: In this paper, the rapidity of accumulation of surface layers and their characteristics in stands of Scots pine (Pinus sylvestris), Norway spruce (Picea abies), birch (Betula verrucosa) and Douglas fir (Pseudotsuga menziesii) in the territory of the Training Forest Enterprise in Kostelec nad Cernymi lesy, at the altitude 430 m a.s.l., on the site of nutrient-poor gleyed soils.
Abstract: The afforestation of agricultural lands was carried out under different site and ecological conditions, including lower and medium elevated localities. The present study documents the rapidity of accumulation of surface layers and their characteristics in stands of Scots pine (Pinus sylvestris), Norway spruce (Picea abies), birch (Betula verrucosa) and Douglas fir (Pseudotsuga menziesii) in the territory of the Training Forest Enterprise in Kostelec nad Cernymi lesy, at the altitude 430 m a.s.l., on the site of nutrient-poor gleyed soils. The plots were compared with the neighbouring continuously forested site covered with old pine-spruce stand and with near-situated arable field. During the first roughly 40 years, considerable changes were documented on the afforested plots. Forest-floor humus layers in the coniferous stands have already been formed, the humus forms being more favourable compared with the old forest site. Acidification and loss of nutrients run in the upper mineral horizons. These processes were also responsible for the less favourable character of the forest soil in the old stand. Birch showed minor shifts of soil properties in the mineral horizon compared to the conifers; the surface humus accumulation was not observed there yet. The lowest degradation among conifers was shown in Douglas fir, intensively taking up deficient nutrients on the other hand.
TL;DR: While forest succession had a large influence on the amount of CWD in different decay classes, it had no effect on CWD distribu - tion among the different size classes.
Abstract: Coarse woody debris (CWD) is an important structural and functional component in forests in Northern Iran. In this study we determine the temporal patterns of CWD in Kheyroud Forests by examining the CWD volume in different decay classes and size classes along a chronosequence of secondary forest succession. The volume of CWD followed the general "U-shaped" temporal trend: the highest in the late successional forest (51.25 m 3 .ha -1 ), lowest in the middle successional forest (25.95 m 3 .ha -1 ) and intermediate in the early successional forest (37.05 m 3 .ha -1 ). The late successional forest had a larger amount of logs, snags and stumps than the other two forests. In contrast, the snag volume did not differ between the late and middle successional forest. CWD in decay classes III and V was greater in the late successional forest than that in the other two forests, while CWD in decay classes II and I did not differ among the three successional forests. CWD in class II and I was significantly higher in the early successional forest than that in the middle successional forest. In the early and middle successional forests, CWD in early decay class was dominated by Carpinus betulus L. followed by Fagus orientalis Lipsky. In the late successional forest, CWD in early decay class was dominated by Fagus orientalis while CWD in the late decay class was dominated by Carpinus betulus. While forest succession had a large influence on the amount of CWD in different decay classes, it had no effect on CWD distribu - tion among the different size classes. Our results suggest that both anthropogenic and natural disturbances have had a long-term effect on the distribution of CWD among three forests.
TL;DR: In this paper, the effects of slope and traffic intensity on soil compaction, rutting and forest floor removal was evaluated on a skid trail in the natural forest of north of Iran.
Abstract: In this study, the effects of slope and traffic intensity on soil compaction, rutting and forest floor removal was evaluated on a skid trail in the natural forest of north of Iran. Combination of two levels of slope 20% (SC2) and three levels of traffic (one, five and nine traffics) were studied. Treatment plots, with three replications, were established on the skid trail prior to skidding. The results of this study showed that all bulk densities were con - siderably higher in SC2 than in SC1 and average soil bulk densities were measured from 1.07 (g∙cm -3 ) to 1.23 (g∙cm -3 ) on skid trail and 0.91 (g∙cm -3 ) in undisturbed areas. With the increment of traffic, soil compaction increased but there was no significant difference among the three levels of traffic frequency in SC1 whereas it was significant between one and five cycles in SC2. Greatest rut depth was measured as 12 cm at nine traffics in SC2, although increase of traffic density caused deeper rut depth at all slope treatments, but it was higher at the SC2 in comparison to SC1. Litter mass decreased considerably on the skid trail with the increasing in slope and traffic. No important difference has been de - tected between SC1 and SC2 in terms of Litter mass removal. These results provide clear evidence that soil disturbance on steep trail is intensified.
TL;DR: In this paper, the authors used the PHENIPS model to evaluate climate change impacts on the distribution and voltinism of spruce bark beetle in the Czech Repub - lic. 1961-1990.
Abstract: Climate change is expected to influence the distribution and population dynamics of many insect pests, with potential severe impacts on forests. Spruce bark beetle Ips typographus (L.) (Col.: Curculionidae, Scolytinae) is the most important forest insect pest in Europe whose development is strictly regulated by air temperature. Therefore, climate change is anticipated to induce changes in the pest's distribution and development. We used the PHENIPS model to evaluate climate change impacts on the distribution and voltinism of spruce bark beetle in the Czech Repub - lic. Two future time periods - 2025-2050 (near future) and 2075-2100 (distant future) - are addressed. The period 1961-1990 is used as the reference. We found that while a two-generation regime dominated in the Czech Republic in the reference period, significant three-generation regime regions are projected to appear in the near future. In the distant future, the three-generation regime can be expected to occur over all existing coniferous stands in the Czech Republic. The analysis of altitudinal shift of n-generation regime regions indicates noticeable expansion of Ips typogra- phus development to higher elevations, leading for example to disappearance of one-generation regime regions in the distant future. Uncertainties and limitations of the presented findings are discussed as well.
TL;DR: In this paper, the aboveground biomass data on Masson pine (Pinus massoniana) from nine provinces in southern China were used to develop generalized single-tree biomass models using both linear mixed model and dummy variable model methods.
Abstract: The estimation of forest biomass is important for practical issues and scientific purposes in forestry The estimation of forest biomass on a large-scale level would be merely possible with the application of generalized single-tree biomass models The aboveground biomass data on Masson pine ( Pinus massoniana) from nine provinces in southern China were used to develop generalized single-tree biomass models using both linear mixed model and dummy variable model methods An allometric function requiring only diameter at breast height was used as a base model for this purpose The results showed that the aboveground biomass estimates of individual trees with identical diameters were different among the forest origins (natural and planted) and geographic regions (provinces) The linear mixed model with random effect parameters and dummy model with site-specific (local) parameters showed better fit and prediction performance than the population average model The linear mixed model appears more flexible than the dummy variable model for the construction of generalized single-tree biomass models or compatible biomass models at different scales The linear mixed model method can also be applied to develop other types of generalized single-tree models such as basal area growth and volume models
TL;DR: In this paper, a field production study was conducted for a manual harvesting system using a chainsaw in a Caspian hardwood forest site, where a selective cut was performed on a 42-hectare tract with an average slope of 30 percent.
Abstract: A field production study was conducted for a manual harvesting system using a chainsaw in a Caspian hardwood forest site. A selective cut was performed on a 42-hectare tract with an average slope of 30 percent. Felling time per tree was most affected by diameter at breast height and by the distance among harvested trees. The gross and net production rate was 20.6 m3 and 26.1 m3 per hour/one person, respectively. The unit cost considering the gross and net production rate was 1.05 USD/m3 and 0.81 USD/m3, respectively. The significant variables included diameter at breast height (D) and distance among harvested trees (L) for the time expenditure model. This regression function is statistically significant at α = 0.01.
TL;DR: In this paper, the authors investigated the felling and skidding damage to residual trees in a selectively cutting operation in the Caspian forest of Iran, where the logging operation was performed by chainsaw and cable skidder.
Abstract: The felling and skidding damage to residual trees was investigated in a selectively cutting operation in the Caspian forest of Iran. The logging operation was performed by chainsaw and cable skidder. Prelogging, after felling and skidding operations residual tree injuries (species, DBH and damage) were inventoried by systematic plot sampling. Two types of tree damage were observed: destroyed and injured. In this study felling operations mainly injured trees whereas skidding was the main cause of destruction. The percentage of destroyed and injured residual trees by felling operations was 1.4% and 3.4%, whereas the percentage of destroyed and injured residual trees by skid - ding operations was 5.2% and 11.1%. About 87% of destroyed trees were found in the DBH class smaller than 22.5 cm. Maple and Alder were the most damaged trees among the other trees species. Damage to the lower bole and wood damaged intensity were the most common type of injury. To reduce the stand damage, skid trails should be planned before felling and felling directions should be predetermined. In the selection cutting management, limiting logging damage to residual trees must therefore remain a major objective.
TL;DR: In this paper, the authors showed the importance of proper estima- tion of carbon stocks in coarse woody debris (CWD), which accounts for the decay process of CWD, on an example of a natural mountainous spruce forest located in Central Europe.
Abstract: Although coarse woody debris (CWD) represents one of the major carbon pools in natural forest ecosystems, little information is available about its CWD carbon stocks. This study demonstrates the importance of proper estima - tion of carbon stocks in CWD, which accounts for the decay process of CWD, on an example of a natural mountainous spruce forest located in Central Europe. The study accounts for aboveground coarse woody debris including standing dead trees, lying deadwood, and naturally formed stumps. Basic mensurational information (diameter, height, decay class) about dead wood was collected in the field during the inventory of the forests of the nature reserve Babia hora. The data were used for the calculation of CWD timber volume. In the next step, CWD timber volume was converted to carbon stock using the carbon proportion of 50.1% and density values of decay classes derived from the informa - tion published elsewhere. The analysis revealed that when CWD timber volume was converted to carbon stocks using the basic wood density of fresh wood, C stocks were overestimated by 40% or more depending on the developmental stage and elevation. The results also revealed that as the elevation increases, CWD carbon stocks decrease and the differences between the developmental stages diminish.
TL;DR: In this article, a mixed-specific regression model with 45 sample trees using different input variables such as di- ameter, height and wood density was developed to estimate the aboveground biomass of beechhornbeam stands.
Abstract: A better understanding of the carbon biomass from forests is needed to improve both models and mitiga - tion efforts related to the global C cycle and greenhouse gas mitigation. Despite the importance of Hyrcanian forests for biodiversity conservation, no study with biomass destruction has been done to predict biomass and carbon pools from this forest. Mixed-specific regression equations with 45 sample trees using different input variables such as di - ameter, height and wood density were developed to estimate the aboveground biomass of beech-hornbeam stands. All the sample trees were harvested and the diameter at breast height (DBH) spanned from 31 to 104 cm so as to represent the diameter distribution reported in the beech-hornbeam stand management. Using only diameter as an input vari - able, the stands regression model estimates the aboveground biomass of the stand with an average deviation of 19% (R 2 = 0.92; SEE = 0.22). Adding height as the second explanatory variable slightly improved the estimation with an average deviation of 18% ( R 2 adj = 0.95; SEE = 0.17). Adding only height or wood density did not improve significantly the estimations. Using the three variables together improved the precision of bole biomass prediction of stands with an average deviation of 10.3% (R 2 adj = 0.965; SEE = 0.167). 68% of the observed variation in the aboveground biomass of beech-hornbeam stands was explained only by diameter.
TL;DR: It was revealed that the tree species clearly affected macrofauna whereas nitrogen fixation did not, and the results suggest that the earthworm distribution is regulated by leaf litter quality whereas the macroFauna richness is regulatedby leaf litter mass, soil organic carbon and leaf litter Mg.
Abstract: plantations than in the others, whereas they were lowest in E camaldulensis Tree species and nitrogen fixing trees significantly influenced the soil macrofauna richness The results suggest that the earthworm distribution is regulated by leaf litter quality (Ca, C and N) whereas the macrofauna richness is regulated by leaf litter mass, soil organic carbon and leaf litter Mg Totally, it was revealed that the tree species clearly affected macrofauna whereas nitrogen fixation did not
TL;DR: A software solution of the algorithms, and an example of different thinning concepts for selected forest stands is presented at the end of the paper along with a discussion about the advantages and disadvantages of the thinning model compared to the SILVA 2.2 model.
Abstract: The paper deals with a proposal for a thinning model for the growth simulator SIBYLA. The model is based on an analytical-causal modeling approach. Some partial theorems are tested on experimental data from thinning sample plots. The model is composed of the following components: the model of bio-sociological tree status, the model for score of existence, the model for type of selection, the model for amount of thinning, and the aggregated model of the thinning concept. The appropriate combination of type and amount of thinning allows the user to perform the following thinning concepts: thinning from below, thinning from above, neutral thinning, crop tree thinning, target diameter thinning, target frequency (equilibrium) curve thinning, clear cutting, and thinning by list (interactive thinning). A software solution of the algorithms, and an example of different thinning concepts for selected forest stands is presented at the end of the paper along with a discussion about the advantages and disadvantages of the thinning model compared to the SILVA 2.2 model.