Comprehensive Stability Evaluation Of Three Typical Communities In State-owned Forest Farm Of Jiangle County Based On TOPSIS Method

The study of the stability of forest communities is mainly directed at natural forests.There are few studies on planted forests.The stability of plantation has a significant relationship with the maintenance of productivity and the maintenance of timber quality..It could provide theoretical support for the study of the stability of the plantation and the maintenance of the productivity of the forest land during the management through the research of the stability of Chinese fir plantations in Jiangle Forest Farm in Fujian Province.In this paper,we mainly use the mixed forest of Chinese fir and broad-leaved forest,mixed forest of Chinese fir and bamboo and mixed forest of Chinese fir and pine as the evaluation objects in Fujian Province.Then we establish the evaluation system by using the AHP to get the weights.Finally,TOPSIS method is applied to analyze the stability.Combined with data of woody trees and shrubs collected from 18 standard plots of Chinese fir plantations in forest plots,we get the main conclusions as follows:1.Community stability:Chinese fir and bamboo mixed forest>Chinese fir and pine mixed forest>Chinese fir broad-leaved mixed forest.2.Stability and diversity are related.Final results that the diversity of mixed forests of Chinese fir and pine mixed forest>Chinese fir and broad-leaved mixed forest>Chinese fir and bamboo are consistent with the ranking results,indicating that diversity could represent part of stability,but it does not fully represent stability.3.In the mixed forest of Chinese fir and bamboo,although the distribution of bamboo in the forest is larger than that of masson pine and broad-leaved species,the leaves of bamboo are less,and the trunk is straight which allow more air and sunshine get into stand.It means that the distribution of bamboo has affected the habitat condition under the forest to a certain extent,and promoted the stability of the community development.4.The stability index measured by the M-Godron assay was 0.23 for Chinese fir mixed forest,0.24 for Chinese fir mixed forest,and 0.33 for Chinese fir broad-leaved mixed forest.The value of the stability index was defined as a value close to 20/80 for steady state which mean they were all close to the stable state defined by the stability index except for the Chinese fir and broad-leaved mixed forest.5.The potential of dominant tree species was 0.23%for young seedlings and 18.18%for young trees in a mixed forest of Chinese fir and bamboo,and the total value was greater than 6.88%for mixed forests of Chinese fir and pine and 6.87%for Chinese fir and broad-leaved mixed forest.6.Site quality of mixed forest of Chinese fir and broad-leaved trees(933.01)>mixed forest of Chinese fir and bamboo(841.86)>mixed forest of Chinese fir and pine(823.02).The site quality of mixed forest of Chinese fir and broad·leaved trees was higher than that of the other two stands.7.The best spatial structure is that the neighboring trees all have different species,the tree height is lower than the reference tree,and the distribution is moderate.The average mixed degree of Chinese fir and broad-leaved mixed forest is 0.26,the average size ratio is 0.48,and the average angular dimension is 0.46.It is known that in the Chinese fir and broad-leaved mixed forest,the tree speeies distribution shows that the same speeies distribution is more concentrated,and the adjacent tree species overall compared with the reference tree,the degree of mutual obstruction between the tree species is not large and tihe distribution is relatively discrete.Therefore,the spatial structure of the Chinese fir and broad-leaved mixed forest is slightly better than that of the other two stands.