柯西河流域森林覆盖度的空间分布及变化分析

Spatial distribution and change analysis of forest cover in Koshi River Basin

森林是陆地生态系统的重要组成部分,对改善生态环境、维护生态平衡具有不可替代的作用。本文以柯西河流域为研究区,采用Global Forest Watch数据,通过空间叠加分析、转移矩阵等方法,分析研究区内不同地形因子森林覆盖度的分布及变化特征。结果表明:1)研究区森林以中森林覆盖度为主,占研究区森林总面积的31.16%,不同的森林覆盖度占森林总面积的比例基本差别不大;森林覆盖度随海拔和坡度的增加呈现先增加后减少的趋势,其中,森林覆盖度随着海拔变化趋势更显著;森林覆盖度随坡向变化为西北坡>北坡>东北坡>西坡>东坡>西南坡>东南坡>南坡;2)从2000年到2010年柯西河流域森林的总面积增加了651.28 km^2,不同的森林覆盖等级之间均发生了相互转移,从转出来看,变化最为显著的为中高森林覆盖度,转出面积为3171.66 km^2,从转入来看,中森林覆盖度的转入面积最大,为3652.00 km^2;3)从2000年到2010年稳定区占据一定的优势地位,森林覆盖度减少的区域面积为7325.68 km^2,森林覆盖度增加的区域面积为5352.25 km^2,森林覆盖度增加的区域小于减少的区域;4)不同因子对森林覆盖度的变化具有不同的影响,但是,森林覆盖度减少的面积大于增加的面积。

Forest is an important part of terrestrial ecosystem,and it plays an irreplaceable role in improving ecological environment and maintaining ecological balance.Using the data of Global Forest Watch,the distribution characteristics and changes of forest cover of different terrain factors in the Koshi River Basin(KRB)were analyzed through the methods of spatial overlay analysis,transfer matrix,etc.Following are the major findings:1)The forest in the KRB was mainly medium cover forest,accounting for 31.16%of the total forest area.The forest cover increased first and then decreased with the increase of altitude and slope.Among them,the forest cover changed more significantly with the increase of altitude.The forest cover was decreased along the aspects as follows:the northwest aspect>north aspect>northeast aspect>west aspect>east aspect>southwest aspect>southeast aspect>south aspect.2)From 2000 to 2010,the total area of forest increased 651.28 km^2 in the KRB,and the different levels of forest cover were transferred to each other.The most significant change happened in the medium-high cover forest,and the area of transferred-out was 3171.66 km^2.While the transferred-in area of medium cover forest was the largest,which was 3652.00 km^2.3)Between 2000 and 2010,the stable zone occupied a dominant position. The area with reduced forest cover was 7325.68 km^2, while the area with increased forest cover was5352.25 km^2. 4) Different factors had different impacts on the change of forest cover, and the area of decrease of forest coverwas greater than increase during the study period.