“三北”防护林建设以来河西走廊林地变化的遥感监测

 为了对中国\!三北\"防护林工程重点建设区河西走廊的防风固沙林工程建设成效进行客观评估,选取4期Landsat MSS、TM/ETM数据,在GIS技术支持下对1978—2007年期间面状林地的动态进行遥感监测。监测结果表明,整个研究区林地面积呈先下降后上升趋势,表现为1978—1990年林地面积明显减少,1990—2000年林地面积大幅度上升,2000—2007年林地呈缓慢上升状态;在不同空间范围内,山区各县林地变化较为缓和,平原区各县林地变化较为明显。在此基础上,分析不同林地变化特征,得出人为因素是本地区林地变化的主要原因。

Remote Sensing Monitoring of Forest Land Change in Hexi Corridor since Construction of the Three-North Shelterbelt Project

In order to assess the effect of the \!Three-North Shelterbelt Project\" in Hexi Corridor,we analyzed dynamic change of forest lands in Hexi Corridor based on Landsat data in 1978,1990,2000 and 2007 and GIS.Results showed that forest land area decreased at first and then increased during the 30 years.In detail,forest land area decreased significantly from 1978 to 1990,increased substantially from 1990 to 2000,and increased slowly from 2000 to 2007.In terms of spatial pattern,forest land area had a little change in mountain area while its change was not significant in plain area in Hexi Corridor.According to analysis on forest land transformation process,it was concluded that human factors were dominant driving factors in forest land area change in Hexi Corridor from1978 to 2007.