Artificial woodland degradation in semi-arid agro-pastoral transitional area: conceptual model and status assessment

Abstract

Planting trees was used as one of cost-effective measures for desertification control in arid and semi-arid areas of China. Woodland degradation, however, is becoming an inevitable issue in these areas. In this paper, a typical county, Ejin Holo County, Inner Mongolia, China was selected for its assessment of artificial woodland degradation. A conceptual model for woodland degradation was delineated qualitatively based on field sampling survey, and four model-based indicators as humidity index (HI), vegetation index (NDVI), soil type (ST) and soil erosion modulus (EM) were screened out and used to a GIS-based method for artificial woodland degradation assessment in this semi-arid agro-pastoral transitional area. All the indicator layers were overlaid and desertification assessed using simplified equation with equal weights for each indicators. The assessment results showed that in 336.09 km² of total woodland area, 311.35 km² woodland were under degradation, and the area for slight, medium, severe degradation was 78.97, 119.73 and 112.65 km², respectively. It was suggested that much attention should be paid on woodland improvement and plant species selection, especially shrub species, before revegetation in similar areas.

Keywords

Artificial woodland / Degradation model / GIS / Degradation assessment / Semi-arid area