Forest Health Assessment At Stand Scale

The forest stand of Jingouling Farm was investigated for forest health assessment, located in Changbai Mountain of northeastern China. This research was based on the theory that structure determined function and different tree species with a healthy state have different stand structures. Forest health status was evaluated in eight forest types for different tree species in this area. Forest health assessment indicator system included nine indicators and ten sub-indicators from the three aspects of productivity, stability and ecological function. The indicator system had strong applicability and sought to reflect the natural stand condition completely because most of the data could be obtained from Forest Resource Inventory.The normal interval analysis and the average value were used to divide indicator standards in this paper. We took different forest types with different standards into account when dividing by stocking volume per unit area. Therefore, we should consider forest types as an indicator standard further. Weights of different tree species were controlled by the criteria layer when those of their indicators were assigned. AHP was used in determining the final target weight. Fuzzy comprehensive approach was adopted in distinguishing the comprehensive membership for each subcompartment, namely, health membership for each subcompartment determined by the maximum weight.We came to the conclusions as follows after forest health assessment was based on different forest species and forest types in this area.(1) The proportion of forest area with good quality and health in mixed forest itself was higher than that in coniferous mixed forest and that in broadleaved mixed forest through health evaluation of different tree species and forest types. The proportions for the three forest types were 44.6 percent,15.4 percent and 14.9 percent, respectively. The ratio of forest area with good quality and health in artificial mixed forest itself was higher than that in artificial pure forest. (2) The result indicated that many subcompartments of timber forest were in sub-health condition, with an area of 8327.5 hm2. And it accounted for 56.4 percent of the total timber forest. Besides, most of subcompartments of protection forest were in health condition, with an area of 568.8 hm2 and it accounted for 66.3 percent of the total protection forest.Therefore, appropriate stand tending measures should be taken to improve the forest structures of timber forest, so as to gain the optimum economic benefits.