This study aimed to demonstrate change in spatial correlation between Korean pine （Pinus koraiensis Sieb. et Zucc.） and three rare species, and change in spatial distribution of four species in response to a range o...This study aimed to demonstrate change in spatial correlation between Korean pine （Pinus koraiensis Sieb. et Zucc.） and three rare species, and change in spatial distribution of four species in response to a range of selective cutting intensities. We sampled three plots of mixed Korean pine and broad-leaf forest in Lushuihe Forestry Bureau of Jilin province, China. Plot 1, a control, was unlogged Korean pine broad-leaf forest. In plots 2 and 3, Korean pine was selectively cut at 15 and 30 % intensity, respectively, in the 1970s. Other species were rarely cut. We used point-pattern analysis to research the spatial distributions of four tree species and quantify spatial correlations between Korean pine and the other three species, Amur linden （Tilia amurensis Rupr.）, Manchurian ash （Fraxinus mandshurica Rupr.）, and Mongolian oak （Quercus mongolica Fisch.） in all three plots. The results of the study show that selective cutting at 15 % intensity did not significantly change either the species spatial patterns or the spatial correlation between Korean pine and broadleaf species. Selective cutting at 30 % intensity slightly affected the growth of Korean pine and valuable species in forest communities, and the effect was considered nondestructive and recoverable.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
Background： Frequent outbreaks of insects and diseases have been recorded in the native forests of western North America during the last few decades, but the distribution of these outbreaks has been far from uniform....Background： Frequent outbreaks of insects and diseases have been recorded in the native forests of western North America during the last few decades, but the distribution of these outbreaks has been far from uniform. In some cases, recent climatic variations may explain some of this spatial variation along with the presence of expansive forests composed of dense, older trees. Forest managers and policy makers would benefit if areas especially prone to disturbance could be recognized so that mitigating actions could be taken. Methods： We use two ponderosa pine-dominated sites in western Montana, U.S.A. to apply a modeling approach that couples information acquired via remote sensing, soil surveys, and local weather stations to assess where bark beetle outbreaks might first occur and why. Although there was a general downward trend in precipitation for both sites over the period between 1998 and 2010 （slope =-1.3, R2 = 0.08）, interannual variability was high. Some years showed large increases followed by sharp decreases. Both sites had similar topography and fire histories, but bark beetle activity occurred earlier （circa 2000 to 2001） and more severely on one site than on the other. The initial canopy density of the two sites was also similar, with leaf area indices ranging between 1.7-2.0 m2. m-2. We wondered if the difference in bark beetle activity was related to soils that were higher in clay content at site I than at site II. To assess this possibility, we applied a process-based stand growth model （3-PG） to analyze the data and evaluate the hypotheses. Results： We found that when wet years were followed by drier years, the simulated annual wood production per unit of leaf area, a measure of tree vigor, dropped below a critical threshold on site I but not on site II. Conclusion： We concluded that the difference in vulnerability of the two stands to beetle outbreaks can be explained largely by differences in gross photosynthesis attributed to the fact that an equivalent amount of stored water in the rooting zone （100 mm） is extracted less efficiently from fine-textured soils than from coarse-textured ones.展开更多
叶面积的大小可以对树木的生长和生命活动产生深远的影响,进而关系到树木生物量的变化和森林生态的发展趋势,叶面积的研究可以对树木的相关分析起到较为关键的作用。基于黑龙江省48株红松人工林解析木数据和排水法测定的叶面积数据,建...叶面积的大小可以对树木的生长和生命活动产生深远的影响,进而关系到树木生物量的变化和森林生态的发展趋势,叶面积的研究可以对树木的相关分析起到较为关键的作用。基于黑龙江省48株红松人工林解析木数据和排水法测定的叶面积数据,建立基础线性回归模型,后引入随机效应参数构建混合效应回归模型以提高拟合效果和预估精度。在加入树木层次的随机效应时,最终得到的最优混合效应模型含有3个随机效应参数,分别为枝条基径的对数(lnBD)、枝条长度的对数(lnSL)、树高的对数(lnHT)。该模型的R_(a)^(2)=0.86,平均绝对偏差M_(AE)=0.3428,均方根误差R_(MSE)=0.4841,统计指标较仅包含固定效应的基础线性模型均有较好的提高。综合分析得出该模型可以较好地对红松枝条叶面积大小进行描述。基于该模型计算红松树冠叶面积并得到混合效应预估模型,混合模型的R a 2=0.83,R_(MSE)=0.4429。通过检验结果可知该模型可以较好地对红松树冠叶面积进行预估计算,为日后该地区人工红松的经营提供良好的指导方向。展开更多
基金funded by China National Science and Technology Support Program(Grant No.2012BAD21B02)
文摘This study aimed to demonstrate change in spatial correlation between Korean pine （Pinus koraiensis Sieb. et Zucc.） and three rare species, and change in spatial distribution of four species in response to a range of selective cutting intensities. We sampled three plots of mixed Korean pine and broad-leaf forest in Lushuihe Forestry Bureau of Jilin province, China. Plot 1, a control, was unlogged Korean pine broad-leaf forest. In plots 2 and 3, Korean pine was selectively cut at 15 and 30 % intensity, respectively, in the 1970s. Other species were rarely cut. We used point-pattern analysis to research the spatial distributions of four tree species and quantify spatial correlations between Korean pine and the other three species, Amur linden （Tilia amurensis Rupr.）, Manchurian ash （Fraxinus mandshurica Rupr.）, and Mongolian oak （Quercus mongolica Fisch.） in all three plots. The results of the study show that selective cutting at 15 % intensity did not significantly change either the species spatial patterns or the spatial correlation between Korean pine and broadleaf species. Selective cutting at 30 % intensity slightly affected the growth of Korean pine and valuable species in forest communities, and the effect was considered nondestructive and recoverable.
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.
文摘Background： Frequent outbreaks of insects and diseases have been recorded in the native forests of western North America during the last few decades, but the distribution of these outbreaks has been far from uniform. In some cases, recent climatic variations may explain some of this spatial variation along with the presence of expansive forests composed of dense, older trees. Forest managers and policy makers would benefit if areas especially prone to disturbance could be recognized so that mitigating actions could be taken. Methods： We use two ponderosa pine-dominated sites in western Montana, U.S.A. to apply a modeling approach that couples information acquired via remote sensing, soil surveys, and local weather stations to assess where bark beetle outbreaks might first occur and why. Although there was a general downward trend in precipitation for both sites over the period between 1998 and 2010 （slope =-1.3, R2 = 0.08）, interannual variability was high. Some years showed large increases followed by sharp decreases. Both sites had similar topography and fire histories, but bark beetle activity occurred earlier （circa 2000 to 2001） and more severely on one site than on the other. The initial canopy density of the two sites was also similar, with leaf area indices ranging between 1.7-2.0 m2. m-2. We wondered if the difference in bark beetle activity was related to soils that were higher in clay content at site I than at site II. To assess this possibility, we applied a process-based stand growth model （3-PG） to analyze the data and evaluate the hypotheses. Results： We found that when wet years were followed by drier years, the simulated annual wood production per unit of leaf area, a measure of tree vigor, dropped below a critical threshold on site I but not on site II. Conclusion： We concluded that the difference in vulnerability of the two stands to beetle outbreaks can be explained largely by differences in gross photosynthesis attributed to the fact that an equivalent amount of stored water in the rooting zone （100 mm） is extracted less efficiently from fine-textured soils than from coarse-textured ones.
文摘叶面积的大小可以对树木的生长和生命活动产生深远的影响,进而关系到树木生物量的变化和森林生态的发展趋势,叶面积的研究可以对树木的相关分析起到较为关键的作用。基于黑龙江省48株红松人工林解析木数据和排水法测定的叶面积数据,建立基础线性回归模型,后引入随机效应参数构建混合效应回归模型以提高拟合效果和预估精度。在加入树木层次的随机效应时,最终得到的最优混合效应模型含有3个随机效应参数,分别为枝条基径的对数(lnBD)、枝条长度的对数(lnSL)、树高的对数(lnHT)。该模型的R_(a)^(2)=0.86,平均绝对偏差M_(AE)=0.3428,均方根误差R_(MSE)=0.4841,统计指标较仅包含固定效应的基础线性模型均有较好的提高。综合分析得出该模型可以较好地对红松枝条叶面积大小进行描述。基于该模型计算红松树冠叶面积并得到混合效应预估模型,混合模型的R a 2=0.83,R_(MSE)=0.4429。通过检验结果可知该模型可以较好地对红松树冠叶面积进行预估计算,为日后该地区人工红松的经营提供良好的指导方向。
