Study On Forest Ecosystem Health Assessment Of Nature Reserve In Beichuan County

Take the case study of forest ecosystem of nature reserve in Beichuan county for example,based on the outdoor and indoor experiments,this paper builds forest ecosystem health assessment systems and the fuzzy model, and assesses synthetic to forest ecosystem of nature reserve in Beichuan county,the results as follows:(1)According the nature reserve forest actual situation in Beichuan county,this paper proposed a set of forest ecosystem health assessment index system. This index system could be divided into three different classes,such as objective class,element class,and indicator class,including18indicators. Then uses qualitative and quantitative method to screen assessment index system,including10indicators,it analyzes the forest ecosystem of nature reserve in Beichuan county,including three aspects:forest ecosystem vigor,forest ecosystem structure and forest ecosystem resistance.(2)Forest ecosystem structure is the most influential element to forest ecosystem health in the element layer of the forest ecosystem assessment,the weight is0.73. Among the level indicators of the forest ecosystem structure assessment,environmental factor is the most influential element to forest ecosystem health,the weight is0.43, and elevation is the most influential element among the three environmental factor,the weight is0.38,it indicates elevation is the most influential element to forest ecosystem health assessment of nature reserve in Beichuan county.The negative general health of nature reserve increased with elevation,but the general health at an altitude of1500to1800meters is better than that of1400to1500meters,the perhaps reason is the human disturbance at an altitude of1400to1500meters is larger than that of1500to1800meters.(3)The assessment result of forest ecosystem vigor of nature reserve in Beichuan county is health,the value is2.20,but it prevents the trend from the sub-health condition to unhealthy one. The assessment result of forest ecosystem structure of this nature reserve is sub-health,the value is2.88. The assessment result of forest ecosystem resistance of this nature reserve is health,the value is2.115but it prevents the trend from the sub-health condition to unhealthy one. On the whole.the assessment result of forest ecosystem of nature reserve in Beichuan county is sub-health,the value is2.77. (4)The community type at an altitude of1450to1800meters,J.cathayensis Dode-Galla Chinensis+Euptelenpleiospermn-Imperata cylindrica (Linn.) Beauv.is the best in the study area,the perhaps reason is the obvious vertical zonal distribution of vegetation,the forest communities at an altitude of1450to1800meters is evergreen and deciduous broad-leaved forest or deciduous broad-leaved forest,the forest community structure is best. The rest of the four community types are in sub-health.