Riparian Populus euphratica forest is endemic to the arid and desert areas of China. It plays an important role in maintaining the health and stability of arid ecosystems. The aim of this paper is to better the relationship between the P. euphratica forest system and people and to offer a solid basis for scientific management and sustainable utilization of the P. euphratica forest.
In this paper, we take P. euphratica forest occurring in the Khotan watershed as a case study and collected the related data through filed survey. Using these data, we assess the direct and indirect ecological service values (ESVs) of the P. euphratica forest system, using some mathematic and physical methods and economic methods, such as market pricing method, opportunity cost method, water quantity equation method, and shadow project method.
The indirect ESVs are the production of organic matter, climate regulation, soil formation and protection, water regulation, environment purification, biodiversity conservation, and the value of recreation and culture. The direct ESVs are timber production and industrial raw material.
Results from this study showed that the average ESV of the P. euphratica forest system, covering an area of 3.184×104 hm2 in the study region, was 67 million Yuan per year, which accounted for 19.0% of the Khotan region’s gross national production in 2002. Of the total forest’s ESV, the annual value of organic matter production was 19.2 million Yuan, which accounted for 28.7%, followed by biodiversity’s conservation value being 16.4 million Yuan per year, which accounted for 24.5%, and environmental purification value being 12.3 million Yuan per year, which accounted for 18.4%. Moreover, the annual values of climate regulation and soil formation and protection are also significant, which are 7.9 and 7.0 million Yuan and accounted for 11.7% and 10.5% of the total ESV, respectively. For the direct value of the P. euphratica forest system, the value of timber produ ct is found to be 7.6 million Yuan per year and accounted for only 3.3% of the total ESV, which was different from people’s normal thinking. Our results also showed that the economic value is much higher than its investment, and the indirect value is several times higher than the direct value. Thus, we should pay much attention to the forest’s ecosystem service functions in developing forest’s management practices in river origins, as in the case of the P. euphratica forest ecosystem in the Khotan’s watershed. We hope that our study could stimulate more investigation on the assessment of local P. euphratica forests in order to have a better understanding of ecological functions of riparian forests in the arid and desert regions of northwest China.