1995—2014年北洛河流域植被恢复的地形分布特征

Topographical Distribution Characteristics of Vegetation Restoration in the Beiluo River Basin from 1995 to 2014

以1995,2007和2014年Landsat TM影像为数据源,计算归一化植被指数(NDVI),分析退耕还林政策下北洛河流域植被的恢复程度.结果表明,流域三年平均植被覆盖度分别为:46.4%,63.4%和73.4%.上游吴起、志丹等县所在丘陵沟壑区增加态势最明显,三年平均植被覆盖度分别为20.2%,41.64%,51.2%.系统分析流域上游丘陵沟壑区植被恢复在地形上的趋势变化.结果表明:不同高程、坡度和坡向分布带上均表现出植被覆盖度随着时间进展呈现明显好转态势.

Taking the Beiluo river basin as an example, the Landsat TM image data in 1995, 2007 and 2014 were employed and the vegetation coverage was derived to analyze how the vegetation restored. The results showed that the average vegetation coverage in the three years of the whole basin are 46.43%, 63.42%, and 73.4%, respectively. The trends of vegetation distribution on landform were analyzed in the upper reaches of the basin. It is showed that whatever the elevation belts, slope gradient spans, and slope aspect zones were, the vegetation coverage improved distinctively in 1995, 2007 and 2014. Meanwhile, the extent or the area of low vegetation coverage transforming to high vegetation coverage tends to be greater with the elevation lower, slope gradient larger, and slope aspect inclining to be shady. © 2016, Editorial Department of Journal of Northeastern University. All right reserved.