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

References

[1] CCICCD China country paper to combat desertification [M], 1997 Beijing: China Forestry Publishing House 30-31.

[2] CCYHBC Yijin Holo Banner Chronicle [M], 2002 Huhhot: Inner Mongolia People’s Press 178-181.

[3] INCD. International Convention to Combat Desertification [M], 1994 New York: United Nations General Assembly 1-2.

[4] ISSTLP-CAS Exploitation of natural resources and desertification control in Ejin Holo County, Inner Mongolia [M], 1991 Beijing: Science Press 8-10.

[5] Ji F., Ma Y., Fan Z. Soil water regime in Populus euphratica forest on the Tarim River alluvial plain [J]. Acta Phytoecologica Sinica, 2001, 25(1): 17-21.

[6] Mao L., Yu C., Yang X. Causal analysis of desertification in semi-arid agro-pastoral ecotone of China: A case study in Ejin Holo County, Inner Mongolia[J] Chinese Forestry Science and Technology, 2005, 4(3): 11-21.

[7] Thomas D.S.G., Middleton N.J. Desertification: exploding the myth [M], 1994 Chichester: John Wiley&Sons 103-110.

[8] Thornthwaite C.W. An approach toward a rational classification of climate [J]. Geographical Review, 1948, 38: 55-94.

[9] Wade T.G., Wickham J.D., Kepner W.G. Using GIS and a graphical user interface to model land degradation [J]. Geo Info Systems, 1994, 2: 38-42.

[10] Wang L., Shao M. A., Hou Q. C. et al. The analysis to dried soil layer of artificial Robinnia pseudoscacia forestry land in the Yan’an experimental area [J]. Acta Bot. Boreal. — Occident. Sin., 2001, 21: 101-106.

[11] West N.E. Temperate deserts and semi-deserts [M], 1983 Amsterdam: Elsevier Scientific Publishing Company 226-228.

[12] Yang W. The preliminary discussion on soil desiccation of artificial vegetation in the northern regions of China [J]. Scientia Silvae Sinicae, 1996, 32: 78-85.

[13] Yang X., Zhang K., Ci L. Tempo-spatial change of landscape pattern in semi-arid agro-pastoral transition area in recent 20 years—a case study in Ejin Holo County, Inner Mongolia [J]. Journal of Beijing Forestry University, 2005, 27(5): 81-86.

[14] Yang X., Zhang K., Jia B., Ci L. Desertification assessment in China: An overview[J] Journal of Arid Environments, 2005, 63: 517-531.

[15] Zhang X. S. Principles and optimal models for development of Maowusu sandy grassland [J]. Acta Phytoecologica Sinica, 1994, 18: 1-16.