Detecting forest landcape boundary between Mountain Birch and evergreen eoniferous forest in the northern slope of Changbai Mountain

Boundaries between different forest types in Changbai Mountain Eatern China are results from complex interactions between forest ecosystems,topogrphy,and geomorphology.Detecting and quantifying the transitional zones are highly important since high environmental beterogeneity and biodiversity are ofter found within these zpmes.In this study,we used GIS and multivariate statistics techniques(PCA and MSWA) to analyze data from Landsat TM satellite imageries and quantitatively determined the positions and widths of the landscape boundary betweeen mountain birch and evergreen coniferous forests in the northern slope of Changbai Mountain.The results showed that the widths of the landscape boundary ranges from 30-50 m while using the MWW A or/and PC method.Such detected widths are consistent with field transect data that suggest a 50m tranistional zone width.The results further suggest that TM data can be used in combination with GIS and statistical techniques in determining forest landscape boundaries.MSWA is more reliable than PCA,while PCA can also be used to determine the landscape boundary when transects are properly located.     

大兴安岭地区雷击火分析与防治

1 雷击火已成为引发我区森林火灾的主要原因之一 大兴安岭地区地处高纬，受气候和地形的影响，每年4～7月都有雷击闪电发生。来自极地大陆性冷气团或变形的冷气团。通过大兴安岭林区易产生雷暴天气，引发雷击火出现。实践证明，大兴安岭林区是雷击多发区，雷击火已引发多起重特大森林火灾。内蒙大兴安岭地区的雷击火占该区总火源的18％，最多年份可达38％。喜桂图旗、鄂伦春旗和额尔古纳左旗等地的雷击火，在有的年份可占这些地区总火灾的76％。     

太湖,钱塘江源头—临安市森林生态保护与建设问题

本文对太湖和钱墉江源头－临安市的森林生态保护与建设问题作了探讨。认为临安市生态保护和基地建设已取得一定成效，今后应加快实施林业分类经营、适当调整林种和产业结构。 同时建立健全公益林补偿金制和产业结构。同时建立健全公益林补偿金制度，确保农民的增收，使全社会特别是生态公益林的主要投资者一广大农民自觉地保护森林，从根本上促进江湖源头的森林生态的保护和发展。     

过去50年中国森林资源和降水变化的统计分析

论文对过去50年中国森林资源和降水变化进行了统计分析，以期在大尺度上寻找森林资源与降水变化之间的关系。主要结论为：①建国以来我国的森林覆盖率呈上升趋势；②过去50年全国、林区、非林区降水量均呈减少趋势，干旱化趋势明显；③对建国后历次森林资源调查（清查）时段内降水差值（以百分数为单位）、森林覆盖率（以相邻两次变化百分数为单位）变化关系的分析表明，二者的统计关系并不显著，即：过去50年我国森林资源的变化对降水没有显著的影响；④森林影响降水是一个复杂的系统问题，该研究还存在着许多不确定性因素，需进一步实验验证与理论探讨。