The spatial structure rationality evaluation and ideal spatial structure of forest ecosystem is an important and difficult problem in forest management at home and abroad. In order to reveal the reasons why the community structure is simple and the stability of ecosystem is poor, and to take the regulation mechanism of structure in Dongting Lake forest, the research is targeted at East, South, West Dongting Lake area including Junshan Island, Longshan, Longhu forest farm on Chishan Island, Minglang mountain, Changde forest farm, Hefu Forest farm and natural secondary forest of Taoyuan County. Utilizing the ecosystem internal balance and homogenizing principle of the ecology, in the forest ecological system (plaque) scale, it analyses the spatial structure of mixed, competed and spatial distribution pattern. And then the heterogeneity goal of optimized stand spatial structure is proposed, which has multiple sub鄄goals in mixed, competed and spatial distribution pattern. Meanwhile the heterogeneity index of single tree and stand spatial structure is also defined, and the evaluation index, evaluation method and evaluation standard of stand spatial structure heterogeneity is determined. By applying the proposed evaluation method to the Dongting Lake area secondary forest heterogeneity evaluation, the results show that: in the fifteen Dongting Lake wetlands under investigation, the forest stand average homogeneity evaluation index is 0. 2517. There are 12 stands in the grade 1 and grade 2 which is accounted for 80% , and only 3 stands in the 3 grade accounted for only 20% in the five grades of homogeneity index. However, it lacks of the grade 4 and grade 5 ideal stand

Individual tree biomass equations have been frequently used in ecological and forestry research over the last 60 years. They represent a powerful tool to understand forest productivity, nutrient cycling, and carbon sequestration, and they are used to estimate other structural and functional characteristics of forest ecosystems. Current attempts to develop above鄄 ground biomass equations for Larix forests in northeast China have been mainly focused on only one species or applied to the genus Larix as a whole. However, generalized above鄄ground biomass equations for Larix could be used to estimate the average relationship between above鄄ground biomass and different independent variables and also variations among different Larix species. We developed generalized biomass equations for different Larix species by using Larix olgensis and Larix gmelinii. In this study, a total of nine tree variables that were able to predict above鄄ground biomass in Larix species were examined using biomass equations. The results show that D, H, and CW contributed significantly to predict above鄄ground