Vegetation Restoration And Plantation Sustainability Assessment On The Loess Plateau

The ecological environment of Wuqi Country has been improved since the implementation of project of returning cropland to woodland or grassland. As a case study, change of vegetation coverage, the situation of vegetation restoration in Wuqi County, the minimal ecological water requirement, the suitable ecological water requirement of main types of vegetation, the indicators of plantation sustainablity assessment were analyzed based on the technology of Geographic Information System, Remote Sensing, methodology of statistics, meteorology, hydrology and landscape ecology. This study aimed to provide an advisory opinion of customized measure of plantation sustainable assessment and enhanced the achievement of returning cropland to woodland or grassland project of Wuqi Country. Main study conclusions of the paper are shown as follows:(1) Land area with vegetation coverage more than 30% was not up to 1% of the total area of Wuqi in 2000, but it made up to 91.96% of the total area in 2009. From 2000 to 2009, the area of shrub-land and woodland expanded obviously on the gentle slope, but vegetation recovery on steep and sunny slope was very slow. Woodland, shrub land and sparse woodland were in the extended-state. Mid-coverage grassland, low-coverage grassland and cropland decreased in area, being in the shrinking-state.(2) With continuously dry year prolonging from 1998 to 2006, the precipitation of the growing season failed to reach the suitable ecological water requirement of Woodland, shrub land and high-coverage grassland, which limited the plantation sustainability.(3)Plantation sustainablity assessment of twenty-one sample plots was analyzed on site scale. Assessment grade was classified as optimized sustainability, general sustainability, poor sustainability and extremely poor sustainability. Seven sample plots were classified as optimized sustainability, six sample plots were belonged to general sustainability,5 sample plots were classified as poor sustainability, three sample plots were belonged to extremely poor sustainability, and two thirds of total sample plots were reached the standard of basic plantation sustainability.