The Effect Of Forest Thinning On The Southern Slope Of Qinling Mountains Red Birch Forest Growth And Carbon Sequestration Capacity

To find out the optimal thinning method and management way of Betula albo-sinensis Burk.forest and give suggestion to managers,different thinning intensities with CK,5%,10%,5%,20% and 25% of Betula albo-sinensis Burk.sample plots were set in Xunyangba forest farms in shaanxi province.Thinning effects on the growth and nitrogen fixation of Betula albo-sinensis Burk.after 5 years were analyzed by the heights,volumes of timber,basal areas,biomass and carbon storage and successive years changes.It was showed that thinning intensities had significant effect on the growth of Betula albo-sinensis Burk...When thinning intensity was 15%,the volume of timber and basal area were 26.19% and 23.12%,respectively,which were the maximum.When thinning intensity was 20%,the biomass increased 13.85%.When thinning intensity was 25%,the height went up 5.03%.With different hinning intensities,growth rates of biomass,volumes of timber and basal areas had growth movements,while the growth rate of height had a upward trend.When thinning intensity was 15%,heights,volumes of timber,basal areas and biomass had optimal values.Thinning changed diameter class and increased spatial biotope of Betula albo-sinensis Burk..The biomass of individual tree increased significantly,while the effect of thinning on the height of tree was not obvious.When thinning intensity was 15%,heights,volumes of timber,basal areas and biomass of diameter class had optimal values.The growth of the middle and low diameter class contributed greatly to the growth of the whole forest.Thinning could increase middle and low diameter class forests grow fast.When thinning intensity was 15%,carbon storage had optimal value and low diameter class could increased carbon storage significantly.