Evaluation Of Forest Ecosystem Stability Of Different Types Of Degraded Forest By Induced Transformation

We considered different degradation type of degraded forest as the research object in Greater Hinggan Mountains, and reformed respectively to degraded forest of cutting interference and fire interference in2003by belt cutting. Then we researched the influence of different types of degraded forest to biodiversity, soil physical and chemical properties, the litter and soil respiration by induced transformation. Results showed that,(1) For the biodiversity, This paper used principal component analysis method.We divided the species richness index, diversity index and evenness index of the tree layer, the shrub layer and herb layer into three main component, and comprehensively studied the change of biological diversity of different types of forest degradation after induced transformation. After comparison to all species diversity of each experimental, we could get the result that:the biodiversity of the sample plots diversity from low to high is as follows:fire interference in2007to CK3<fire interference in2003to CK2<no interference sample CK<cutting interference to CK1. As recovery time went on, community biodiversity of each type of degradation was increasing gradually. and slowly closed to the level of no interference sample. Belt cutting was reformed as10m bandwidth, and community biodiversity of sample recovered the best.(2)For the soil physical and chemical properties, Contrasting to no interference sample CK, the soil capillary porosity and total porosity of different types of degraded forest sample were elevated, while soil moisture content was dropped. Soil sample capillary porosity of each type of degradation performed no significant difference (P>0.05) to no interference sample CK by analysis of variance. Soil pH value of cutting interference to CK1in2003and fire interference to CK2were reduced, while fire interference to CK3in2007was increased, and all kinds of soils were in weakly acidic. Contrasting to no interference sample CK, soil organic matter, hydrolyzed N, effective P, available K quality score of different types of degraded forest sample were reduced, while the Total K quality score was elevated. Soil total N, and the P quality score of no interference to CK1and fire interference to CK3in2007were increased, while soil total N, and the P quality score of fire interference to CK2in2003was dropped. The soil physical and chemical properties of each belt sample had improved, in cutting interference test, the degree of change of soil physical and chemical properties S1<S3<S2, on fire interference test in2003, the degree of change of soil physical and chemical properties S4<S6<S5.(3) For the litter, Total volume and maximum capacity of litters of different types of degraded forest samples was in great changes, and no decomposition level, half decomposition level and total volume of litters were reduced. The proportion of total volume and maximum capacity of litters of not decomposition level were less than half decomposition level of each sample plot. Belt cutting accelerated the decomposition rate of litters. We used6m and10m bandwidth to reform which could reduce effectively the influence of cutting transformation to the performance of the water of litters.(4)For the soil respiration, Soil carbon flux of different types of degraded forest sample were less than no interference CK,and soil respiration rate of each sample ranked from low to high as follows, CK3<CK2<CK1<CK. In cutting interference sample, soil carbon flux of each effect was increased with the width, and soil carbon flux of each effect was larger than cutting interference CK1. Soil respiration rate of each effect was as follows, CK1<S1<S2<S3. In fire interference sample in2003, soil carbon flux of each effect were larger than cutting interference CK2,and soil respiration rate of the effect was as follows, CK2<S4<S5<S6.(5) We used the fuzzy membership function value to evaluate forest community’s stability, the community’s stability of each type of degraded forest sample in the research areas order: CK> CK1> CK2> CK3. In cutting interference and fire interference sample, community stability of belt cutting sample was higher than check plots, and it was the best community stability for belt cutting transformation by10m bandwidth.The research results provide scientific reference for recovery of different types of degraded forests in the Greater Hinggan Mountains.