Shannon diversity index and its evenness are used to analyze the difference of higher plants in brod-leaved Korean pine forest and secondary birch forest. The result show that the species diversity of higher plants in...Shannon diversity index and its evenness are used to analyze the difference of higher plants in brod-leaved Korean pine forest and secondary birch forest. The result show that the species diversity of higher plants in secondary bireh forest is higher than that in broad-leaved Korean pine forest. Many of rare species existing in broad-leaved Korean pine forest are few or absent in secondary birch forest. The diversity of herbs both in broad-leaved Korean pine and in secondary birch forest is very rich and has a great change in different scesons.展开更多
The mutual-belt selective cutting was conducted in the secondary poplar-birch forests. The changes of environmental factors after cutting were observed. The environmental factors of effect belts(cutting belts) of 15m ...The mutual-belt selective cutting was conducted in the secondary poplar-birch forests. The changes of environmental factors after cutting were observed. The environmental factors of effect belts(cutting belts) of 15m in width had great changes. 10-m effect belts had unnoticed changes in environmental factors. The reserved belts with 10-m effect belts had a greater increase in DBH growth rate and volume growth rate. The reserved belts for 6-m and 8-m effect belts had lower increase in DBH and volume. The environmental factors of 6-m and 8-m effect belts did not change much. comparing with their reserved belts. Cluster analysis and principal component analysis for environmental factors between each two belts were also made. and the results proved that 10-m cutting belt is the best way for management of the secondary poplar-birch forests.展开更多
The community ecology of Poplar-Birch forest in China was studied. It includes the distribution, classification. structure. growth.regeneration, succession and forest management. Research direction of community ecolog...The community ecology of Poplar-Birch forest in China was studied. It includes the distribution, classification. structure. growth.regeneration, succession and forest management. Research direction of community ecology and forest management for PoplarBirch forest was pointed out. Further studies should be made on the relation between stand and ecological environment. the structure and dynamics. nursery role to needle leave trees,target cultivation and classification management. management of the second generation forest and the third generation forest.展开更多
The basic principle of life table method is deseribed, and the method of tree height instead of tree age in static life table is suggested, and it is also discussed that the possibility of natural poplar -birch forest...The basic principle of life table method is deseribed, and the method of tree height instead of tree age in static life table is suggested, and it is also discussed that the possibility of natural poplar -birch forest recover to broad-leaf Korean pine forest on low pitches in the Xiaoxing'an Mountains by this method. If there is no particular situation, Korean pines after high than 5m under natural Poplar-birch forest will basically survive and make their way into dominant callopy accompanied by climax broad-leaf species.展开更多
Assessment of regional forest carbon stocks and underlying controls is critical for guiding forest management in the context of carbon sequestration. We investigated the variations in tree biomass carbon stocks relati...Assessment of regional forest carbon stocks and underlying controls is critical for guiding forest management in the context of carbon sequestration. We investigated the variations in tree biomass carbon stocks relating to forest types, and estimated the total tree biomass carbon stocks and projected gains through natural stand development by 2020 and 2050 in the Daqing Mountain Nature Reserve based on Category II data of the Forest Inventory of Inner Mongolia for the period ending 2008. Over a total area of 388,577 ha,this nature reserve currently stores an estimated 2221 Gg C in tree aboveground biomass alone, with potential to grow by more than 30 % to reach 2938 Gg C by 2020 and nearly double to 4092 Gg C by 2050 through natural development of the existing forest stands. The tree biomass carbon density and potential gain in tree biomass carbon stocks vary markedly among forest types and with stand development.The variations in the potential change of tree biomass carbon density for the periods 2008–2020 and 2008–2050 among forest types partly reflect the varying relationships of tree biomass carbon density with stand age for different tree species, and partly are attributable to variations in the stand age structure among different forest types. Of the major forest types, the ranking of projected changes in tree biomass carbon density are not consistent with variations in the relationship between tree biomass carbon density and stand age, neither are they explainable by variations in stand age structures, implying the interactive effect between forest type and stand dynamics on temporal changes in tree biomass carbon density. Birch rank highest for future biomass carbon sequestration because of its dominance in cover area and better age structure for potential gain in tree biomass carbon stocks. Poplar and larch were out-performers compared to other forest types given their greater contribution to total tree biomass carbon stocks relative to their distributional areas. Findings in this study illustrate that protection and proper management of under-aged forests can deliver marked gains in biomass carbon sequestration. This is of great importance to policy-makers as well as to scientific communities in seeking effective solutions for adaptive forest management and mitigation of anthropogenic greenhouse gases emissions using forest ecosystems.展开更多
Background： Generalized height-diameter curves based on a re-parameterized version of the Korf function for Norway spruce （Piceo abies （L.） Karst.）, Scots pine （Pinus sylvestris L.） and silver birch （Betula pe...Background： Generalized height-diameter curves based on a re-parameterized version of the Korf function for Norway spruce （Piceo abies （L.） Karst.）, Scots pine （Pinus sylvestris L.） and silver birch （Betula pendula Roth） in Norwa are presented. The Norwegian National Forest Inventory （NFI） is used as data base for estimating the model parameters. The derived models are developed to enable spatially explicit and site sensitive tree height imputatio in forest inventories as well as future tree height predictions in growth and yield scenario simulations. Methods： Generalized additive mixed models （gamm） are employed to detect and quantify potentially non-linear effects of predictor variables. In doing so the quadratic mean diameter serves as longitudinal covariate since stand ag as measured in the NFI, shows only a weak correlation with a stands developmental status in Norwegian forests. Additionally the models can be locally calibrated by predicting random effects if measured height-diameter pairs are available. Based on the model selection of non-constraint models, shape constraint additive models （scare） were fit tc incorporate expert knowledge and intrinsic relationships by enforcing certain effect patterns like monotonicity. Results： Model comparisons demonstrate that the shape constraints lead to only marginal differences in statistical characteristics but ensure reasonable model predictions. Under constant constraints the developed models predict increasing tree heights with decreasing altitude, increasing soil depth and increasing competition pressure of a tree. / two-dimensional spatially structured effect of UTM-coordinates accounts for the potential effects of large scale spatial correlated covariates, which were not at our disposal. The main result of modelling the spatially structured effect is lower tree height prediction for coastal sites and with increasing latitude. The quadratic mean diameter affects both the level and the slope of the height-diameter curve and both effects are positive. Conclusions： In this investigation it is assumed that model effects in additive modelling of height-diameter curves which are unfeasible and too wiggly from an expert point of view are a result of quantitatively or qualitatively limited data bases. However, this problem can be regarded not to be specific to our investigation but more general since growth and yield data that are balanced over the whole data range with respect to all combinations of predictor variables are exceptional cases. Hence, scare may provide methodological improvements in several applications by combining the flexibility of additive models with expert knowledge.展开更多
以内蒙古地区牙克石林业管理局的大兴安岭天然白桦林(Betula platyphylla)为研究对象,利用198块样地数据分析天然白桦林林分碳密度与各林分变量之间的关系,建立碳密度预测基础模型,同时将立地条件(草类白桦林、杜鹃-越桔白桦林、榛子白...以内蒙古地区牙克石林业管理局的大兴安岭天然白桦林(Betula platyphylla)为研究对象,利用198块样地数据分析天然白桦林林分碳密度与各林分变量之间的关系,建立碳密度预测基础模型,同时将立地条件(草类白桦林、杜鹃-越桔白桦林、榛子白桦林)作为哑变量引入到预测模型中,对不同林型的林分碳密度进行预测,为林业研究中碳密度模型的构建以及森林碳汇工作提供思路和方法。结果表明,天然白桦林林分碳密度基础模型决定系数(R^(2))为0.703,均方根误差(RMSE)为8.615 t/hm^(2),赤池信息量(Akaike information criterion,AIC)为841.206,贝叶斯信息量(Bayesian Information Criterion,BIC)为851.071。引入立地条件哑变量后,R^(2)有所增大,最大达到0.818,RMSE均小于等于8.241 t/hm^(2),说明模型具有较好的稳定性,预估参数较为精确。哑变量模型的AIC均小于等于541.431,BIC均小于等于550.320。哑变量模型能够反映不同立地条件下碳密度的变化,在模型的拟合和检验方面都显示适合于研究地区林分碳密度的预测,为天然白桦林碳密度估算提供参考。展开更多
文摘Shannon diversity index and its evenness are used to analyze the difference of higher plants in brod-leaved Korean pine forest and secondary birch forest. The result show that the species diversity of higher plants in secondary bireh forest is higher than that in broad-leaved Korean pine forest. Many of rare species existing in broad-leaved Korean pine forest are few or absent in secondary birch forest. The diversity of herbs both in broad-leaved Korean pine and in secondary birch forest is very rich and has a great change in different scesons.
文摘The mutual-belt selective cutting was conducted in the secondary poplar-birch forests. The changes of environmental factors after cutting were observed. The environmental factors of effect belts(cutting belts) of 15m in width had great changes. 10-m effect belts had unnoticed changes in environmental factors. The reserved belts with 10-m effect belts had a greater increase in DBH growth rate and volume growth rate. The reserved belts for 6-m and 8-m effect belts had lower increase in DBH and volume. The environmental factors of 6-m and 8-m effect belts did not change much. comparing with their reserved belts. Cluster analysis and principal component analysis for environmental factors between each two belts were also made. and the results proved that 10-m cutting belt is the best way for management of the secondary poplar-birch forests.
文摘The community ecology of Poplar-Birch forest in China was studied. It includes the distribution, classification. structure. growth.regeneration, succession and forest management. Research direction of community ecology and forest management for PoplarBirch forest was pointed out. Further studies should be made on the relation between stand and ecological environment. the structure and dynamics. nursery role to needle leave trees,target cultivation and classification management. management of the second generation forest and the third generation forest.
文摘The basic principle of life table method is deseribed, and the method of tree height instead of tree age in static life table is suggested, and it is also discussed that the possibility of natural poplar -birch forest recover to broad-leaf Korean pine forest on low pitches in the Xiaoxing'an Mountains by this method. If there is no particular situation, Korean pines after high than 5m under natural Poplar-birch forest will basically survive and make their way into dominant callopy accompanied by climax broad-leaf species.
基金funded by the Program for Public–Welfare Forestry of the State Forestry Administration of China(Grant No.201104008)
文摘Assessment of regional forest carbon stocks and underlying controls is critical for guiding forest management in the context of carbon sequestration. We investigated the variations in tree biomass carbon stocks relating to forest types, and estimated the total tree biomass carbon stocks and projected gains through natural stand development by 2020 and 2050 in the Daqing Mountain Nature Reserve based on Category II data of the Forest Inventory of Inner Mongolia for the period ending 2008. Over a total area of 388,577 ha,this nature reserve currently stores an estimated 2221 Gg C in tree aboveground biomass alone, with potential to grow by more than 30 % to reach 2938 Gg C by 2020 and nearly double to 4092 Gg C by 2050 through natural development of the existing forest stands. The tree biomass carbon density and potential gain in tree biomass carbon stocks vary markedly among forest types and with stand development.The variations in the potential change of tree biomass carbon density for the periods 2008–2020 and 2008–2050 among forest types partly reflect the varying relationships of tree biomass carbon density with stand age for different tree species, and partly are attributable to variations in the stand age structure among different forest types. Of the major forest types, the ranking of projected changes in tree biomass carbon density are not consistent with variations in the relationship between tree biomass carbon density and stand age, neither are they explainable by variations in stand age structures, implying the interactive effect between forest type and stand dynamics on temporal changes in tree biomass carbon density. Birch rank highest for future biomass carbon sequestration because of its dominance in cover area and better age structure for potential gain in tree biomass carbon stocks. Poplar and larch were out-performers compared to other forest types given their greater contribution to total tree biomass carbon stocks relative to their distributional areas. Findings in this study illustrate that protection and proper management of under-aged forests can deliver marked gains in biomass carbon sequestration. This is of great importance to policy-makers as well as to scientific communities in seeking effective solutions for adaptive forest management and mitigation of anthropogenic greenhouse gases emissions using forest ecosystems.
基金supported by the Norwegian Institute of Bioeconomy Research(NIBIO)
文摘Background： Generalized height-diameter curves based on a re-parameterized version of the Korf function for Norway spruce （Piceo abies （L.） Karst.）, Scots pine （Pinus sylvestris L.） and silver birch （Betula pendula Roth） in Norwa are presented. The Norwegian National Forest Inventory （NFI） is used as data base for estimating the model parameters. The derived models are developed to enable spatially explicit and site sensitive tree height imputatio in forest inventories as well as future tree height predictions in growth and yield scenario simulations. Methods： Generalized additive mixed models （gamm） are employed to detect and quantify potentially non-linear effects of predictor variables. In doing so the quadratic mean diameter serves as longitudinal covariate since stand ag as measured in the NFI, shows only a weak correlation with a stands developmental status in Norwegian forests. Additionally the models can be locally calibrated by predicting random effects if measured height-diameter pairs are available. Based on the model selection of non-constraint models, shape constraint additive models （scare） were fit tc incorporate expert knowledge and intrinsic relationships by enforcing certain effect patterns like monotonicity. Results： Model comparisons demonstrate that the shape constraints lead to only marginal differences in statistical characteristics but ensure reasonable model predictions. Under constant constraints the developed models predict increasing tree heights with decreasing altitude, increasing soil depth and increasing competition pressure of a tree. / two-dimensional spatially structured effect of UTM-coordinates accounts for the potential effects of large scale spatial correlated covariates, which were not at our disposal. The main result of modelling the spatially structured effect is lower tree height prediction for coastal sites and with increasing latitude. The quadratic mean diameter affects both the level and the slope of the height-diameter curve and both effects are positive. Conclusions： In this investigation it is assumed that model effects in additive modelling of height-diameter curves which are unfeasible and too wiggly from an expert point of view are a result of quantitatively or qualitatively limited data bases. However, this problem can be regarded not to be specific to our investigation but more general since growth and yield data that are balanced over the whole data range with respect to all combinations of predictor variables are exceptional cases. Hence, scare may provide methodological improvements in several applications by combining the flexibility of additive models with expert knowledge.
文摘以内蒙古地区牙克石林业管理局的大兴安岭天然白桦林(Betula platyphylla)为研究对象,利用198块样地数据分析天然白桦林林分碳密度与各林分变量之间的关系,建立碳密度预测基础模型,同时将立地条件(草类白桦林、杜鹃-越桔白桦林、榛子白桦林)作为哑变量引入到预测模型中,对不同林型的林分碳密度进行预测,为林业研究中碳密度模型的构建以及森林碳汇工作提供思路和方法。结果表明,天然白桦林林分碳密度基础模型决定系数(R^(2))为0.703,均方根误差(RMSE)为8.615 t/hm^(2),赤池信息量(Akaike information criterion,AIC)为841.206,贝叶斯信息量(Bayesian Information Criterion,BIC)为851.071。引入立地条件哑变量后,R^(2)有所增大,最大达到0.818,RMSE均小于等于8.241 t/hm^(2),说明模型具有较好的稳定性,预估参数较为精确。哑变量模型的AIC均小于等于541.431,BIC均小于等于550.320。哑变量模型能够反映不同立地条件下碳密度的变化,在模型的拟合和检验方面都显示适合于研究地区林分碳密度的预测,为天然白桦林碳密度估算提供参考。
