K. Rukomojnikov, S. Vedernikov, Victoriia olegovna Kuptcova
Background and Purpose: The article is devoted to the reduction of energy consumption necessary for delimbing. Materials and Methods: Branch delimbing method includes feeding the tree trunk through the ring formed by the delimbing knives and simultaneous reciprocator movement of the delimbing knives along the axis of the processed trunk. The distinctive feature of the construction is the presence of the beater unit comprising a pusher and a piston mounted inside a sealed housing. Results: As a result of the suggested construction the force of the beater impact of the delimbing knife is increased. Using this method, the branches are removed not only due to the force generated when the knives come in contact with branches pushed by feed rolls moving the trunk, but also due to extra beater stress affecting the delimbing knife. The use of the aforesaid method and the construction of the mechanism allows to reduce energy consumption necessary for the delimbing process. Conclusions: The design of harvesting and processing head proposed in this article can be used in the design and manufacture of logging machines and mechanisms. The technical solution may be an interesting advance of the delimbing process when processing trees, especially when cutting big branches or when cutting forces are temporarily higher than average force values.
{"title":"Modernization of Harvesting and Processing Head","authors":"K. Rukomojnikov, S. Vedernikov, Victoriia olegovna Kuptcova","doi":"10.15177/seefor.19-10","DOIUrl":"https://doi.org/10.15177/seefor.19-10","url":null,"abstract":"Background and Purpose: The article is devoted to the reduction of energy consumption necessary for delimbing. \u0000Materials and Methods: Branch delimbing method includes feeding the tree trunk through the ring formed by the delimbing knives and simultaneous reciprocator movement of the delimbing knives along the axis of the processed trunk. The distinctive feature of the construction is the presence of the beater unit comprising a pusher and a piston mounted inside a sealed housing.\u0000Results: As a result of the suggested construction the force of the beater impact of the delimbing knife is increased. Using this method, the branches are removed not only due to the force generated when the knives come in contact with branches pushed by feed rolls moving the trunk, but also due to extra beater stress affecting the delimbing knife. The use of the aforesaid method and the construction of the mechanism allows to reduce energy consumption necessary for the delimbing process. \u0000Conclusions: The design of harvesting and processing head proposed in this article can be used in the design and manufacture of logging machines and mechanisms. The technical solution may be an interesting advance of the delimbing process when processing trees, especially when cutting big branches or when cutting forces are temporarily higher than average force values.","PeriodicalId":54023,"journal":{"name":"SEEFOR-South-East European Forestry","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45563677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Stojnić, M. Drekić, S. Orlović, A. Tepavac, L. Kesić, Z. Galic, M. Kebert
Background and Purpose: Due to the ability to uptake and accumulate heavy metals (HM) in their aboveground tissues, trees may be used for phytoremediation purposes, but also as bioindicators of environmental pollution. The aims of the present study were: a) to investigate the content and temporal variation of the studied HMs in different plant organs during the period of intensive leaf falling (September-October), in two species from genus Quercus; b) to evaluate the observed HMs content relative to plausible ranges of element concentration in foliar litter, as recommended by ICP Forests Foliar Co-ordinating Centre (IFFCC). Material and Methods: The contents of zinc (Zn), manganese (Mn), copper (Cu) and iron (Fe) were assessed in the litterfall (i.e. leaves and branches) of Quercus petraea (Matt.) Liebl. and Quercus robur L. grown at two ICP Forests Level II monitoring plots (Fruška Gora and Odžaci, Serbia). Plant material was sampled during September-October 2018 and analyzed by atomic absorption spectrophotometry. Results: Comparing the content of investigated HMs in foliar litter and branches of Q. robur and Q. petraea, notably higher concentrations of Mn and Fe have been observed in the foliage of both species, whereas Zn and Cu concentrations were higher in collected branch material of both of the above-mentioned tree species. The results further showed that, when compared to plausible ranges of element concentrations in foliar litter, given by ICP Forests Foliar Co-ordinating Centre (IFFCC), average concentrations of Fe and Zn in the leaves were within suggested limits, whereas certain concentrations of Mn and Cu exceeded the proposed ranges. Furthermore, the content of the studied HMs in plant material of both Quercus species significantly varied during sampling period. Conclusions: Although it was observed that concentrations of certain HMs were beyond plausible limits recommended by IFFCC, our results were in accordance with the findings of other authors who studied HMs content in Quercus species grown in natural forests. For that reason, these limits should be considered optionally, i.e. in the cases when the results significantly deviate from the suggested values. Moreover, we believe that the observed variation in the HMs content during sampling period is related to the sampling procedure commonly applied at ICP Forests monitoring plots, which is indirectly associated with the capacity of trees to accumulate HMs and their phenological properties.
{"title":"Heavy Metals Content in Foliar Litter and Branches of Quercus petraea (Matt.) Liebl. and Quercus robur L. Observed at Two ICP Forests Monitoring Plots","authors":"S. Stojnić, M. Drekić, S. Orlović, A. Tepavac, L. Kesić, Z. Galic, M. Kebert","doi":"10.15177/seefor.19-11","DOIUrl":"https://doi.org/10.15177/seefor.19-11","url":null,"abstract":"Background and Purpose: Due to the ability to uptake and accumulate heavy metals (HM) in their aboveground tissues, trees may be used for phytoremediation purposes, but also as bioindicators of environmental pollution. The aims of the present study were: a) to investigate the content and temporal variation of the studied HMs in different plant organs during the period of intensive leaf falling (September-October), in two species from genus Quercus; b) to evaluate the observed HMs content relative to plausible ranges of element concentration in foliar litter, as recommended by ICP Forests Foliar Co-ordinating Centre (IFFCC).\u0000 Material and Methods: The contents of zinc (Zn), manganese (Mn), copper (Cu) and iron (Fe) were assessed in the litterfall (i.e. leaves and branches) of Quercus petraea (Matt.) Liebl. and Quercus robur L. grown at two ICP Forests Level II monitoring plots (Fruška Gora and Odžaci, Serbia). Plant material was sampled during September-October 2018 and analyzed by atomic absorption spectrophotometry.\u0000 Results: Comparing the content of investigated HMs in foliar litter and branches of Q. robur and Q. petraea, notably higher concentrations of Mn and Fe have been observed in the foliage of both species, whereas Zn and Cu concentrations were higher in collected branch material of both of the above-mentioned tree species. The results further showed that, when compared to plausible ranges of element concentrations in foliar litter, given by ICP Forests Foliar Co-ordinating Centre (IFFCC), average concentrations of Fe and Zn in the leaves were within suggested limits, whereas certain concentrations of Mn and Cu exceeded the proposed ranges. Furthermore, the content of the studied HMs in plant material of both Quercus species significantly varied during sampling period.\u0000 Conclusions: Although it was observed that concentrations of certain HMs were beyond plausible limits recommended by IFFCC, our results were in accordance with the findings of other authors who studied HMs content in Quercus species grown in natural forests. For that reason, these limits should be considered optionally, i.e. in the cases when the results significantly deviate from the suggested values. Moreover, we believe that the observed variation in the HMs content during sampling period is related to the sampling procedure commonly applied at ICP Forests monitoring plots, which is indirectly associated with the capacity of trees to accumulate HMs and their phenological properties.","PeriodicalId":54023,"journal":{"name":"SEEFOR-South-East European Forestry","volume":"1 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41802049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background and Purpose: Black walnut ( Juglans nigra L.) was one of the first forest tree species introduced and acclimated from North America to Europe in the 17th century. Although native to North America, black walnut is now naturalized and widely planted throughout Europe. In Hungary, this species has played an important role in forest management. Black walnut can grow on various sites, but careful site selection and well-planned management practices are needed to produce successful plantations. Due to the increasing interest in black walnut growing in many countries this study complied with the aim of giving a summary on the base of research and improvement connected with the species over the past decades. Materials and Methods: Black walnut produces a well-closing, favourably differentiated stand structure in consequence of the great genetic diversity of single trees. It utilizes well the leaks of the tending cuttings. In this manner, because of its quick height growth, the systematic, individual selective method can be favourably combined with more frequent stem number reduction. The objective of tending should be to produce a high proportion of good quality saw logs from stands of yield class I, II, III and IV, and some other smaller-dimension industrial wood from stands of yield class V and VI. Conclusions: In Hungary, black walnut is one of the most valuable exotic tree species, mainly because of its wood excessively used in furniture industry. Black walnut is used in furniture industry both as solid wood and veneer. This species is among the most expensive furniture woods in the world due to its appealing surface figure and colour. Its wood is also used for making musical instruments, turned and carved ornaments, statues and marquetry. Black walnut stands are to be important in carbon sequestration, soil stabilization, and water quality protection as well.
背景与目的：黑胡桃（Juglans nigra L.）是17世纪从北美引进并适应欧洲的首批森林树种之一。虽然黑胡桃原产于北美洲，但现在已经归化并在整个欧洲广泛种植。在匈牙利，该物种在森林管理中发挥了重要作用。黑胡桃可以在不同的地点生长，但要想种植成功，需要仔细的选址和精心规划的管理实践。由于许多国家对黑胡桃的种植越来越感兴趣，本研究旨在总结过去几十年来与黑胡桃相关的研究和改进。材料和方法：黑胡桃由于单株遗传多样性大，形成了紧密、分化良好的林分结构。它很好地利用了照料岩屑的渗漏。通过这种方式，由于其高度快速增长，系统的、个体选择性的方法可以与更频繁的茎数减少相结合。照料的目标应该是从一、二、三和四级产量的林分中生产出高比例的优质锯材，从五和六级产量的林木中生产出一些其他较小尺寸的工业木材。结论：在匈牙利，黑胡桃是最有价值的外来树种之一，主要是因为其木材在家具工业中被过度使用。黑胡桃在家具工业中既用作实木也用作单板。由于其诱人的表面形状和颜色，该物种是世界上最昂贵的家具木材之一。它的木材也被用于制作乐器、车削和雕刻的装饰品、雕像和镶嵌。黑胡桃林在固碳、土壤稳定和水质保护方面都具有重要意义。
{"title":"Ecology and Management of Black Walnut (Juglans nigra L.) in Hungary","authors":"K. Rédei, M. Takacs, Tamás Kiss, Z. Keserű","doi":"10.15177/seefor.19-12","DOIUrl":"https://doi.org/10.15177/seefor.19-12","url":null,"abstract":"Background and Purpose: Black walnut ( Juglans nigra L.) was one of the first forest tree species introduced and acclimated from North America to Europe in the 17th century. Although native to North America, black walnut is now naturalized and widely planted throughout Europe. In Hungary, this species has played an important role in forest management. Black walnut can grow on various sites, but careful site selection and well-planned management practices are needed to produce successful plantations. Due to the increasing interest in black walnut growing in many countries this study complied with the aim of giving a summary on the base of research and improvement connected with the species over the past decades.\u0000Materials and Methods: Black walnut produces a well-closing, favourably differentiated stand structure in consequence of the great genetic diversity of single trees. It utilizes well the leaks of the tending cuttings. In this manner, because of its quick height growth, the systematic, individual selective method can be favourably combined with more frequent stem number reduction. The objective of tending should be to produce a high proportion of good quality saw logs from stands of yield class I, II, III and IV, and some other smaller-dimension industrial wood from stands of yield class V and VI.\u0000 Conclusions: In Hungary, black walnut is one of the most valuable exotic tree species, mainly because of its wood excessively used in furniture industry. Black walnut is used in furniture industry both as solid wood and veneer. This species is among the most expensive furniture woods in the world due to its appealing surface figure and colour. Its wood is also used for making musical instruments, turned and carved ornaments, statues and marquetry. Black walnut stands are to be important in carbon sequestration, soil stabilization, and water quality protection as well.","PeriodicalId":54023,"journal":{"name":"SEEFOR-South-East European Forestry","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.15177/seefor.19-12","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46009468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pande Trajkov, T. Dubravac, Vladimir Tanovski, Ljupco Nestororvski, K. Sotirovski, Zdravko Trajanov
Background and Purpose: Coppicing is the most widely used silvicultural system in North Macedonia and coppice forests together with shrubs cover cca. 69% of the forest cover area. Pure and mixed stands of oak coppice forests alone cover about 50% of the total forest area subject to current Forest Management Plans. In general, coppices are routinely managed, especially when coppicing as a system is planned to be continued. However, sustainability can be threatened if attention is not paid regarding the age of trees/stands and the presence of undesired tree species. The purpose of this study was to determine: (1) quantitative and qualitative aspects of planned management activities in oak coppices throughout the country, (2) the resprouting potential of over-mature oak coppices, and (3) their potential for generative regeneration. Materials and Methods : We analyzed all official forest management plans in the country, in order to assess planned activities and the methods of management. Additionally, 21 experimental plots were set in order to determine the resprouting potential of over-mature (85 to 95 years) coppices of Quercus petraea and Q. frainneto which previously have been subject of clear-cutting. We took a total count of sprouts on all experimental plots, while generative regeneration seedlings were counted on 4 schematically positioned subplots in each experimental plot. Sprouts and generative seedlings were categorized by height. Results and Conclusions: According to the data from forest management plans, coppicing is planned to remain as a management system on 401,636 ha, of the total of 450,975 ha of oak coppice forests. Indirect conversion to high forests is planned on 39,137 ha, while direct conversion with substitution is planned for 10,202 ha. In field trials, resprouting was registered on only 38% of the stools. Generative regeneration was recorded in both oak species in numbers which indicate good potential for conversion of oak coppice stands into high forests by seed felling. However, numerous sprouts of other species ( Corylus avellana, Fraxinus ornus, Acer heldreichii), which reach up to 3 meters in height within two seasons, are potentially dangerous for dominating oak seedlings.
{"title":"Coppice Forest Management Planning and the Regeneration Potential of Pure and Mixed Oak Coppice Forests in North Macedonia","authors":"Pande Trajkov, T. Dubravac, Vladimir Tanovski, Ljupco Nestororvski, K. Sotirovski, Zdravko Trajanov","doi":"10.15177/seefor.19-20","DOIUrl":"https://doi.org/10.15177/seefor.19-20","url":null,"abstract":"Background and Purpose: Coppicing is the most widely used silvicultural system in North Macedonia and coppice forests together with shrubs cover cca. 69% of the forest cover area. Pure and mixed stands of oak coppice forests alone cover about 50% of the total forest area subject to current Forest Management Plans. In general, coppices are routinely managed, especially when coppicing as a system is planned to be continued. However, sustainability can be threatened if attention is not paid regarding the age of trees/stands and the presence of undesired tree species. The purpose of this study was to determine: (1) quantitative and qualitative aspects of planned management activities in oak coppices throughout the country, (2) the resprouting potential of over-mature oak coppices, and (3) their potential for generative regeneration.\u0000Materials and Methods : We analyzed all official forest management plans in the country, in order to assess planned activities and the methods of management. Additionally, 21 experimental plots were set in order to determine the resprouting potential of over-mature (85 to 95 years) coppices of Quercus petraea and Q. frainneto which previously have been subject of clear-cutting. We took a total count of sprouts on all experimental plots, while generative regeneration seedlings were counted on 4 schematically positioned subplots in each experimental plot. Sprouts and generative seedlings were categorized by height.\u0000Results and Conclusions: According to the data from forest management plans, coppicing is planned to remain as a management system on 401,636 ha, of the total of 450,975 ha of oak coppice forests. Indirect conversion to high forests is planned on 39,137 ha, while direct conversion with substitution is planned for 10,202 ha. In field trials, resprouting was registered on only 38% of the stools. Generative regeneration was recorded in both oak species in numbers which indicate good potential for conversion of oak coppice stands into high forests by seed felling. However, numerous sprouts of other species ( Corylus avellana, Fraxinus ornus, Acer heldreichii), which reach up to 3 meters in height within two seasons, are potentially dangerous for dominating oak seedlings.","PeriodicalId":54023,"journal":{"name":"SEEFOR-South-East European Forestry","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.15177/seefor.19-20","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49668213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Musić, B. Balic, V. Halilović, J. Knežević, A. Avdagić, A. Ibrahimspahić, A. Lojo
Background and Purpose: Bark thickness and its share in the volume of roundwood are the most important characteristics of the bark, particularly in the process of timber harvesting, and during scaling of processed logs. Therefore it is very important to have at disposal relatively accurate data regarding these characteristics of bark for particular tree species. The main goal of this paper is to investigate the thickness of the bark and its share in the volume of roundwood of Norway spruce. Materials and Methods: The research was carried out in the area of the Canton 10 of the Federation of Bosnia and Herzegovina and it encompassed 393 trees of Norway spruce from 10 cm to 115 cm of thickness at breast height. Measuring of the mean diameter and double thickness of bark was conducted by section method. In total, 4,647 diameters and bark thicknesses were measured in different relative lengths of stems or in average 10.6 measurements per one stem. Results: As an optimal model for the evaluation of double thickness of the bark of Norway spruce depending on mean diameter of roundwood the function with designated determination coefficient of 0.7142 was selected. The obtained results have confirmed the previously defined relations of investigate characteristics, which are as following: a) with the increase of mean diameter of roundwood (section) double bark thickness is increased from 9.26 mm (thickness class 12.5 cm) to 31.65 mm (thickness class 92.5 cm); b) with the increase of mean diameter of roundwood the share of bark in its volume decreased from 14.26% (thickness class 12.5 cm) to 6.73% (thickness class 92.5 cm). Conclusions: By the actual method of estimating bark thickness or the share of bark in the volume of roundwood of Norway spruce in the forestry of the Federation of Bosnia and Herzegovina a significant error was created which increases with the increase of mean diameter. The obtained results point to the necessity of investigation of these bark characteristics in Bosnia and Herzegovina and represent an inevitable starting point for making adequate tables of bark thickness and its percentage share in the volume of roundwood of Norway spruce.
{"title":"Modelling Bark Thickness of Norway Spruce (Picea abies Karst)","authors":"J. Musić, B. Balic, V. Halilović, J. Knežević, A. Avdagić, A. Ibrahimspahić, A. Lojo","doi":"10.15177/seefor.19-17","DOIUrl":"https://doi.org/10.15177/seefor.19-17","url":null,"abstract":"Background and Purpose: Bark thickness and its share in the volume of roundwood are the most important characteristics of the bark, particularly in the process of timber harvesting, and during scaling of processed logs. Therefore it is very important to have at disposal relatively accurate data regarding these characteristics of bark for particular tree species. The main goal of this paper is to investigate the thickness of the bark and its share in the volume of roundwood of Norway spruce. \u0000Materials and Methods: The research was carried out in the area of the Canton 10 of the Federation of Bosnia and Herzegovina and it encompassed 393 trees of Norway spruce from 10 cm to 115 cm of thickness at breast height. Measuring of the mean diameter and double thickness of bark was conducted by section method. In total, 4,647 diameters and bark thicknesses were measured in different relative lengths of stems or in average 10.6 measurements per one stem. \u0000Results: As an optimal model for the evaluation of double thickness of the bark of Norway spruce depending on mean diameter of roundwood the function with designated determination coefficient of 0.7142 was selected. The obtained results have confirmed the previously defined relations of investigate characteristics, which are as following: a) with the increase of mean diameter of roundwood (section) double bark thickness is increased from 9.26 mm (thickness class 12.5 cm) to 31.65 mm (thickness class 92.5 cm); b) with the increase of mean diameter of roundwood the share of bark in its volume decreased from 14.26% (thickness class 12.5 cm) to 6.73% (thickness class 92.5 cm).\u0000Conclusions: By the actual method of estimating bark thickness or the share of bark in the volume of roundwood of Norway spruce in the forestry of the Federation of Bosnia and Herzegovina a significant error was created which increases with the increase of mean diameter. The obtained results point to the necessity of investigation of these bark characteristics in Bosnia and Herzegovina and represent an inevitable starting point for making adequate tables of bark thickness and its percentage share in the volume of roundwood of Norway spruce.","PeriodicalId":54023,"journal":{"name":"SEEFOR-South-East European Forestry","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42312872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background and Purpose: Coppice forests have a particular socio-economic and ecological role in forestry and environmental management. Their production sustainability and spatial stability become imperative for forestry sector as well as for local and global communities. Recently, integrated forest inventory and remotely sensed data analysed with non-parametrical statistical methods have enabled more detailed insight into forest structural characteristics. The aim of this research was to estimate forest attributes of beech coppice forest stands in the Sarajevo Canton through the integration of inventory and Sentinel S2A satellite data using machine learning methods. Materials and Methods: Basal area, mean stand diameter, growing stock and total volume data were determined from the forest inventory designed for represented stands of coppice forests. Spectral data were collected from bands of Sentinel S2A satellite image, vegetation indices (difference, normalized difference and ratio vegetation index) and biophysical variables (fraction of absorbed photosynthetically active radiation, leaf area index, fraction of vegetation cover, chlorophyll content in the leaf and canopy water content). Machine learning rule-based M5 model tree (M5P) and random forest (RF) methods were used for forest attribute estimation. Predictor subset selection was based on wrapping assuming M5P and RF learning schemes. Models were developed on training data subsets (402 sample plots) and evaluations were performed on validation data subsets (207 sample plots). Performance of the models was evaluated by the percentage of the root mean squared error over the mean value (rRMSE) and the square of the correlation coefficient between the observed and estimated stand variables. Results and Conclusions: Predictor subset selection resulted in a varied number of predictors for forest attributes and methods with their larger contribution in RF (between 8 and 11). Spectral biophysical variables dominated in subsets. The RF resulted in smaller errors for training sets for all attributes than M5P, while both methods delivered very high errors for validation sets (rRMSE above 50%). The lowest rRMSE of 50% was obtained for stand basal area. The observed variability explained by the M5P and RF models in training subsets was about 30% and 95% respectively, but those values were lower in test subsets (below 12%) but still significant. Differences of the sample and modelled forest attribute means were not significant, while modelled variability for all forest attributes was significantly lower (p<0.01). It seems that additional information is needed to increase prediction accuracy, so stand information (management classes, site class, soil type, canopy closure and others), new sampling strategy and new spectral products could be integrated and examined in further more complex modelling of forest attributes.
{"title":"Modelling Stand Variables of Beech Coppice Forest Using Spectral Sentinel-2A Data and the Machine Learning Approach","authors":"A. Čabaravdić, B. Balic","doi":"10.15177/seefor.19-21","DOIUrl":"https://doi.org/10.15177/seefor.19-21","url":null,"abstract":"Background and Purpose: Coppice forests have a particular socio-economic and ecological role in forestry and environmental management. Their production sustainability and spatial stability become imperative for forestry sector as well as for local and global communities. Recently, integrated forest inventory and remotely sensed data analysed with non-parametrical statistical methods have enabled more detailed insight into forest structural characteristics. The aim of this research was to estimate forest attributes of beech coppice forest stands in the Sarajevo Canton through the integration of inventory and Sentinel S2A satellite data using machine learning methods. \u0000Materials and Methods: Basal area, mean stand diameter, growing stock and total volume data were determined from the forest inventory designed for represented stands of coppice forests. Spectral data were collected from bands of Sentinel S2A satellite image, vegetation indices (difference, normalized difference and ratio vegetation index) and biophysical variables (fraction of absorbed photosynthetically active radiation, leaf area index, fraction of vegetation cover, chlorophyll content in the leaf and canopy water content). Machine learning rule-based M5 model tree (M5P) and random forest (RF) methods were used for forest attribute estimation. Predictor subset selection was based on wrapping assuming M5P and RF learning schemes. Models were developed on training data subsets (402 sample plots) and evaluations were performed on validation data subsets (207 sample plots). Performance of the models was evaluated by the percentage of the root mean squared error over the mean value (rRMSE) and the square of the correlation coefficient between the observed and estimated stand variables. \u0000Results and Conclusions: Predictor subset selection resulted in a varied number of predictors for forest attributes and methods with their larger contribution in RF (between 8 and 11). Spectral biophysical variables dominated in subsets. The RF resulted in smaller errors for training sets for all attributes than M5P, while both methods delivered very high errors for validation sets (rRMSE above 50%). The lowest rRMSE of 50% was obtained for stand basal area. The observed variability explained by the M5P and RF models in training subsets was about 30% and 95% respectively, but those values were lower in test subsets (below 12%) but still significant. Differences of the sample and modelled forest attribute means were not significant, while modelled variability for all forest attributes was significantly lower (p<0.01). It seems that additional information is needed to increase prediction accuracy, so stand information (management classes, site class, soil type, canopy closure and others), new sampling strategy and new spectral products could be integrated and examined in further more complex modelling of forest attributes.","PeriodicalId":54023,"journal":{"name":"SEEFOR-South-East European Forestry","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47973035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background and Purpose: This study presents the analysis of photosynthetic pigments, proline, total soluble protein, total amino acids, glucose, sucrose, total soluble sugars, total amount of phenolic compounds and flavonoids, malondialdehyde (MDA) and hydrogen peroxide (H2O2) concentration in the leaf samples collected from oriental beech trees, which are naturally spread in Kastamonu Province, Turkey, with differing ages, enzyme activities of ascorbate peroxidase (APX), catalase (CAT) and superoxide dismutase (SOD). Material and Methods: The research was carried out on oriental beech trees (Fagus orientalis L.) of different ages located at 1300 m high elevation in Ahlat Village of Kastamonu Province, Turkey. Oriental beech trees of different ages (≥25, ≥50, ≥100, ≥200 and ≥600 years-old) constituted the material of this study. In leaf samples taken from trees of different ages, photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll and carotenoid), proline, total soluble protein, total amino acid, glucose, sucrose, total soluble sugars, the amount of total phenolic compounds and flavonoids, MDA, H2O2 concentration, enzyme activities of APX, CAT and SOD, as well as the relationship between the total content of C, N and H elements and the tree ages were studied. Results: As a result of the research conducted, significant differences were determined in terms of chlorophyll, total phenolic compound, flavonoid, glucose, amounts of sucrose, nitrogenous compounds, proline, total soluble protein, MDA, H 2O2 concentrations, and the activities of APX, CAT and SOD in the leaves of oriental beech trees with differing ages. The highest content of chlorophyll a was found to be in the youngest age group of ≥25 years. Total chlorophyll is low in young trees and high in middle-aged, old and very old trees. According to the results obtained, it was concluded that the MDA and H2O2 concentrations in the trees did not vary depending on the age of trees only, but also on the genotype, environmental conditions and metabolic activities. It was concluded that the fact that the total chlorophyll, phenolic compounds and sucrose content in oriental beech trees are high and that MDA content is low could have an influence on the long life of ≥600 years-old oriental beech trees. Conclusions: The activity of photosynthesis is related to leaf characteristics more than the age of trees.
背景和目的:本研究分析了土耳其Kastamonu省自然分布的不同树龄东方山毛榉叶片样品的光合色素、脯氨酸、总可溶性蛋白、总氨基酸、葡萄糖、蔗糖、总可溶性糖、酚类化合物和类黄酮总量、丙二醛(MDA)和过氧化氢(H2O2)浓度，以及抗坏血酸过氧化物酶(APX)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)的酶活性。材料与方法:对位于土耳其Kastamonu省Ahlat村海拔1300 m的不同年龄的东方山毛榉(Fagus orientalis L.)进行了研究。不同树龄(≥25年、≥50年、≥100年、≥200年、≥600年)的东方山毛榉构成本研究的材料。研究了不同树龄树木叶片中光合色素(叶绿素a、叶绿素b、总叶绿素和类胡萝卜素)、脯氨酸、总可溶性蛋白、总氨基酸、葡萄糖、蔗糖、总可溶性糖、总酚类化合物和类黄酮含量、MDA、H2O2浓度、APX、CAT和SOD酶活性以及总C、N、H元素含量与树龄的关系。结果:不同树龄的东方山毛榉叶片叶绿素、总酚类化合物、类黄酮、葡萄糖、蔗糖、氮化合物、脯氨酸、总可溶性蛋白、MDA、h2o2浓度以及APX、CAT和SOD活性均存在显著差异。叶绿素a含量以≥25岁年龄组最高。总叶绿素在幼树中较低，在中年树、老树和极老树中较高。结果表明，MDA和H2O2浓度的变化不仅与树龄有关，还与基因型、环境条件和代谢活动有关。综上所述，东洋山毛榉总叶绿素、酚类化合物和蔗糖含量高，MDA含量低可能是东洋山毛榉≥600年树龄长寿的重要因素。结论:光合作用活性与叶片特性的关系大于与树龄的关系。
{"title":"Age-Related Changes of Some Chemical Components in the Leaves of Oriental Beech (Fagus orientalis Lipsky.)","authors":"N. Turfan, S. Ayan, E. Yer, H. Özel","doi":"10.15177/seefor.19-15","DOIUrl":"https://doi.org/10.15177/seefor.19-15","url":null,"abstract":"Background and Purpose: This study presents the analysis of photosynthetic pigments, proline, total soluble protein, total amino acids, glucose, sucrose, total soluble sugars, total amount of phenolic compounds and flavonoids, malondialdehyde (MDA) and hydrogen peroxide (H2O2) concentration in the leaf samples collected from oriental beech trees, which are naturally spread in Kastamonu Province, Turkey, with differing ages, enzyme activities of ascorbate peroxidase (APX), catalase (CAT) and superoxide dismutase (SOD).\u0000Material and Methods: The research was carried out on oriental beech trees (Fagus orientalis L.) of different ages located at 1300 m high elevation in Ahlat Village of Kastamonu Province, Turkey. Oriental beech trees of different ages (≥25, ≥50, ≥100, ≥200 and ≥600 years-old) constituted the material of this study. In leaf samples taken from trees of different ages, photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll and carotenoid), proline, total soluble protein, total amino acid, glucose, sucrose, total soluble sugars, the amount of total phenolic compounds and flavonoids, MDA, H2O2 concentration, enzyme activities of APX, CAT and SOD, as well as the relationship between the total content of C, N and H elements and the tree ages were studied.\u0000Results: As a result of the research conducted, significant differences were determined in terms of chlorophyll, total phenolic compound, flavonoid, glucose, amounts of sucrose, nitrogenous compounds, proline, total soluble protein, MDA, H 2O2 concentrations, and the activities of APX, CAT and SOD in the leaves of oriental beech trees with differing ages. The highest content of chlorophyll a was found to be in the youngest age group of ≥25 years. Total chlorophyll is low in young trees and high in middle-aged, old and very old trees. According to the results obtained, it was concluded that the MDA and H2O2 concentrations in the trees did not vary depending on the age of trees only, but also on the genotype, environmental conditions and metabolic activities. It was concluded that the fact that the total chlorophyll, phenolic compounds and sucrose content in oriental beech trees are high and that MDA content is low could have an influence on the long life of ≥600 years-old oriental beech trees.\u0000Conclusions: The activity of photosynthesis is related to leaf characteristics more than the age of trees.","PeriodicalId":54023,"journal":{"name":"SEEFOR-South-East European Forestry","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47250484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Nicolescu, Cornelia Hernea, Deborah Bartlett, N. Iacob
Background and Purpose: The aim of this study is to highlight the importance of black locust (Robinia pseudoacacia L.), a North American-originating tree species of major importance in Romania, in extreme site conditions such as sand dunes. In this respect, a Research and Development (R&D) project has been carried out in Carei-Valea lui Mihai Plain (north-west of Romania) since 2016. Materials and Methods: Three sub-compartments were selected in IV Valea lui Mihai Working Circle, Săcueni Forest District: two pure natural regenerations by root suckers of black locust at different ages (sub-compartments 3B and 52A%) and a mixed black locust - black cherry stand (sub-compartment 23D). Biometrical measurements and analyses as well as biomass estimations were performed. A thorough statistical analysis using the data on initial, extracted and residual trees/stands was also performed. Results: The main outputs of the project are as follows: (1) Black locust was established naturally by root suckers and the stocking of newly established stands can be as high as 50,000 suckers·ha-1; (2) The initial growth of black locust regeneration is quick and the young regeneration can close the canopy in 1-2 years, resulting in an appropriate dune fixation and wind erosion control; (3) The young pure or mixed black locust-dominated stands are left untended until the first cleaning-respacing (mean diameter 5-6 cm), when the stand shows high stocking/density and a wide variation in tree size. This intervention is from below, heavy (intensity over 25% by number of trees or basal area) and of negative selection type, removing mostly low Kraft’s class, dead or dying, and defective trees. Conclusions: This R&D project has shown the high potential of black locust to establish naturally by root suckers after a low coppice cut and stump removal, as well as the fast initial growth of regenerated black locust. The quick canopy closure of young regeneration results in an appropriate dune fixation and wind erosion control.
背景和目的：本研究的目的是强调黑蝗虫（Robinia pseudoacia L.）的重要性，它是一种原产于北美的树种，在罗马尼亚具有重要意义，在沙丘等极端场地条件下具有重要意义。在这方面，自2016年以来，在Carei Valea lui Mihai平原（罗马尼亚西北部）开展了一个研发项目。材料和方法：在IV Valea lui-Mihai工作圈中选择了三个子区，Săcueni林区：不同年龄的黑蝗虫（子区3B和52A%）和一个黑蝗虫-黑樱桃混合林（子区23D）的两个纯自然再生。进行了生物测量和分析以及生物量估计。还使用初始、提取和残留树木/林分的数据进行了全面的统计分析。结果：该项目的主要成果如下：（1）利用吸根器自然建立了黑蝗虫群落，新建立的林分蓄积量可达5万只·ha-1；（2） 黑蝗虫再生初期生长迅速，幼龄再生可在1-2年内关闭树冠，形成适当的沙丘固定和风蚀控制；（3） 年轻的纯或混合黑蝗虫为主的林分在第一次清理重新造林（平均直径5-6厘米）之前不受干扰，此时林分表现出高放养/密度和树木大小的广泛变化。这种干预措施是从下方进行的，强度大（按树木数量或基底面积计算，强度超过25%），并且是负选择型的，主要清除低卡夫等级、死亡或垂死以及有缺陷的树木。结论：该研发项目显示了黑蝗虫在低矮林和树桩移除后，通过吸根器自然建立的高潜力，以及再生黑蝗虫的快速初始生长。幼树更新的快速树冠闭合导致了适当的沙丘固定和风蚀控制。
{"title":"Regeneration and Early Tending of Black Locust (Robinia pseudoacacia L.) Stands in the North-West of Romania","authors":"V. Nicolescu, Cornelia Hernea, Deborah Bartlett, N. Iacob","doi":"10.15177/SEEFOR.19-14","DOIUrl":"https://doi.org/10.15177/SEEFOR.19-14","url":null,"abstract":"Background and Purpose: The aim of this study is to highlight the importance of black locust (Robinia pseudoacacia L.), a North American-originating tree species of major importance in Romania, in extreme site conditions such as sand dunes. In this respect, a Research and Development (R&D) project has been carried out in Carei-Valea lui Mihai Plain (north-west of Romania) since 2016.\u0000Materials and Methods: Three sub-compartments were selected in IV Valea lui Mihai Working Circle, Săcueni Forest District: two pure natural regenerations by root suckers of black locust at different ages (sub-compartments 3B and 52A%) and a mixed black locust - black cherry stand (sub-compartment 23D). Biometrical measurements and analyses as well as biomass estimations were performed. A thorough statistical analysis using the data on initial, extracted and residual trees/stands was also performed.\u0000Results: The main outputs of the project are as follows: (1) Black locust was established naturally by root suckers and the stocking of newly established stands can be as high as 50,000 suckers·ha-1; (2) The initial growth of black locust regeneration is quick and the young regeneration can close the canopy in 1-2 years, resulting in an appropriate dune fixation and wind erosion control; (3) The young pure or mixed black locust-dominated stands are left untended until the first cleaning-respacing (mean diameter 5-6 cm), when the stand shows high stocking/density and a wide variation in tree size. This intervention is from below, heavy (intensity over 25% by number of trees or basal area) and of negative selection type, removing mostly low Kraft’s class, dead or dying, and defective trees.\u0000Conclusions: This R&D project has shown the high potential of black locust to establish naturally by root suckers after a low coppice cut and stump removal, as well as the fast initial growth of regenerated black locust. The quick canopy closure of young regeneration results in an appropriate dune fixation and wind erosion control.","PeriodicalId":54023,"journal":{"name":"SEEFOR-South-East European Forestry","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49180611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background and Purpose: The sycamore seed bug, Belonochilus numenius (Say, 1831), was recorded for the first time in Europe in 2008, with finds in that same year in two separate locations in Spain and two in France. Since then, it has been reported to be present in 17 European countries. Once it reached Europe, the fast spread and establishment of this species was facilitated both by the increased plant trade and the relative frequency of plane trees ( Platanus x acerifolia, P. orientalis and P. occidentalis ) planted on a wide scale across the continent due to their popularity as urban and peri-urban trees. Materials and Methods: In the summer of 2019 we inspected urban, peri-urban and natural populations and groups of plane trees throughout North Macedonia, on a total of 44 sites, looking for presence of nymphs and adults of this insect on seed balls. We collected specimens and related data and made identification based on specific external characteristics typical of B. numenius. Results: We report the first record of B. numenius in the Republic of North Macedonia from July 2019, from P. x acerifolia in Skopje. Furthermore, after inspecting plane trees throughout the country we report the presence of this insect in 29 cities and towns, 3 peri-urban and in 1 natural population of P. orientalis. Conclusions: From the widespread distribution of this insect species, we conclude that it has entered the territory of North Macedonia many years prior, very likely soon after first records in Serbia in 2011 and Bulgaria in 2012, but has since been overlooked.
背景和目的：悬铃木种子虫Belonochilus numenius（Say，1831）于2008年首次在欧洲被记录，同年在西班牙的两个不同地点和法国的两个地点被发现。自那时以来，据报道，它已在17个欧洲国家出现。一旦到达欧洲，植物贸易的增加和平面树（Platanus x acerifolia、P.orientalis和P.occidentalis）在整个大陆大规模种植的相对频率都促进了该物种的快速传播和建立，因为它们作为城市和近郊树木很受欢迎。材料和方法：2019年夏天，我们在北马其顿共44个地点检查了城市、城市周边和自然种群以及梧桐树群，在种子球上寻找这种昆虫的若虫和成虫。我们收集了标本和相关数据，并根据努美纽斯特有的外部特征进行了鉴定。结果：我们报告了2019年7月北马其顿共和国首次记录的努梅纽斯B.numenius，来自斯科普里的悬铃木P.x acerifolia。此外，在对全国各地的梧桐树进行检查后，我们报告在29个城镇、3个城郊和1个自然种群中存在这种昆虫。结论：从这种昆虫的广泛分布来看，我们得出结论，它在多年前就已经进入北马其顿领土，很可能是在2011年塞尔维亚和2012年保加利亚首次记录后不久，但后来被忽视了。
{"title":"Widespread Distribution of the Sycamore Seed Bug Belonochilus numenius (Hemiptera: Heteroptera: Lygaeidae) Throughout the Republic of North Macedonia","authors":"Katerina Srebrova, Sterja Nacheski, K. Sotirovski","doi":"10.15177/seefor.19-19","DOIUrl":"https://doi.org/10.15177/seefor.19-19","url":null,"abstract":"Background and Purpose: The sycamore seed bug, Belonochilus numenius (Say, 1831), was recorded for the first time in Europe in 2008, with finds in that same year in two separate locations in Spain and two in France. Since then, it has been reported to be present in 17 European countries. Once it reached Europe, the fast spread and establishment of this species was facilitated both by the increased plant trade and the relative frequency of plane trees ( Platanus x acerifolia, P. orientalis and P. occidentalis ) planted on a wide scale across the continent due to their popularity as urban and peri-urban trees. Materials and Methods: In the summer of 2019 we inspected urban, peri-urban and natural populations and groups of plane trees throughout North Macedonia, on a total of 44 sites, looking for presence of nymphs and adults of this insect on seed balls. We collected specimens and related data and made identification based on specific external characteristics typical of B. numenius. Results: We report the first record of B. numenius in the Republic of North Macedonia from July 2019, from P. x acerifolia in Skopje. Furthermore, after inspecting plane trees throughout the country we report the presence of this insect in 29 cities and towns, 3 peri-urban and in 1 natural population of P. orientalis. Conclusions: From the widespread distribution of this insect species, we conclude that it has entered the territory of North Macedonia many years prior, very likely soon after first records in Serbia in 2011 and Bulgaria in 2012, but has since been overlooked.","PeriodicalId":54023,"journal":{"name":"SEEFOR-South-East European Forestry","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48881553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Valentin Cristea, Ș. Leca, Albert Ciceu, S. Chivulescu, O. Badea
Background and Purpose: Romania’s forests are of globally significant value due to their natural characteristics, as similar forests in some other parts of the world have been lost forever. These types of forests, so-called "virgin" and "quasi-virgin (old growth)" forests, are also identified in the Buzau Mountains, which are part of the Eastern Carpathians in Romania (Curvature Region). Materials and Methods: To study and understand the structure and dynamics of primeval forest, four permanent one-hectare research plots were installed in the Penteleu Mountains, part of the Buzau Mountains. All trees with a diameter at breast height (DBH) greater than 80 mm were measured and their main dendrometric characteristics (DBH, height and social position) registered. The forest structure was analysed by fitting different theoretical distribution functions (beta, gamma, gamma 3P, gamma 3P mixt, loglogistic 3p, lognormal 3P and Weibull 3p). The structural homogeneity of the permanent research plots was tested using the Camino index (H) and Gini index (G). Results: For the smaller DBH categories, Norway spruce was relatively shorter in height, but with increasing DBH, the heights of Norway spruce exceeded those of European beech. Stand volume varied between 615 and 1133 m3 per hectare. The area of maximum stability where we encountered the lowest tree height variability was recorded between the 60 cm and 100 cm diameter categories. The Lorenz curve and the Gini index indicated that the studied stands have high structural biodiversity. Conclusions: The results showed that the studied forests have an optimal structural diversity, assuring them a higher stability and multifunctionality. Thus, these forests are models for managed forests.
{"title":"Structural Features of Old Growth Forest from South Eastern Carpathians, Romania","authors":"Valentin Cristea, Ș. Leca, Albert Ciceu, S. Chivulescu, O. Badea","doi":"10.15177/seefor.19-13","DOIUrl":"https://doi.org/10.15177/seefor.19-13","url":null,"abstract":"Background and Purpose: Romania’s forests are of globally significant value due to their natural characteristics, as similar forests in some other parts of the world have been lost forever. These types of forests, so-called \"virgin\" and \"quasi-virgin (old growth)\" forests, are also identified in the Buzau Mountains, which are part of the Eastern Carpathians in Romania (Curvature Region). \u0000Materials and Methods: To study and understand the structure and dynamics of primeval forest, four permanent one-hectare research plots were installed in the Penteleu Mountains, part of the Buzau Mountains. All trees with a diameter at breast height (DBH) greater than 80 mm were measured and their main dendrometric characteristics (DBH, height and social position) registered. The forest structure was analysed by fitting different theoretical distribution functions (beta, gamma, gamma 3P, gamma 3P mixt, loglogistic 3p, lognormal 3P and Weibull 3p). The structural homogeneity of the permanent research plots was tested using the Camino index (H) and Gini index (G).\u0000Results: For the smaller DBH categories, Norway spruce was relatively shorter in height, but with increasing DBH, the heights of Norway spruce exceeded those of European beech. Stand volume varied between 615 and 1133 m3 per hectare. The area of maximum stability where we encountered the lowest tree height variability was recorded between the 60 cm and 100 cm diameter categories. The Lorenz curve and the Gini index indicated that the studied stands have high structural biodiversity.\u0000Conclusions: The results showed that the studied forests have an optimal structural diversity, assuring them a higher stability and multifunctionality. Thus, these forests are models for managed forests.","PeriodicalId":54023,"journal":{"name":"SEEFOR-South-East European Forestry","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45957166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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