Dynamic Change Analysis Of Forest Biomass In Youxian

For forest ecosystem research,forest biomass is an important indicator of forest ecosystems and is the basis for studying forestry problems.Forest biomass can also predict the strength of forest carbon sequestration and provide important parameters for assessing regional forest carbon balance.However,domestic and foreign studies have shown that forest biomass estimation methods still remain in the traditional statistical methods,the spatial distribution of forest biomass and mapping and other aspects of research is not enough,it is difficult to spatial analysis of forest biomass and evaluation,and forest biological The map can directly estimate the forest biomass and the net flux from land use change,so the research is of great importance.In this study,the Landsat remote sensing images of 1999,2004,2009 and 2014 were used in the study area.The data of fixed plots in 1999,2004,2009 and 2014 were combined with three regression models,Estimate forest biomass.The main findings are as follows:(1)The sensitivity factors of inversion of forest biomass in Youxian County were determined,and the results of correlation analysis were used to screen the results.Finally,six inversions were carried out from 14 initial variables,and RGVI The vegetation index has the highest correlation with forest biomass.(2)The optimal regression model based on Landsat image forest biomass was established.The remote sensing inversion model of forest biomass was constructed by stepwise regression,logistic regression and spatial geography weighted regression.The results show that the spatial geography weighted regression model is effective.(3)Estimation of forest biomass in Youxian County in 1999,2004,2009 and 2014 according to spatial geography weighted regression model.Combined with GIS,spatial statistics,analysis and mapping of forest biomass in Youxian County at four different times.(4)The study shows that the area of forest biomass 1-10(t/ha)has increased year by year and reached the maximum in 2009,which means that the proportion of other forest biomass areas decreases year by year,20(t/ha)area ratio decreased,indicating a slight increase in greening levels during 2014.The forest biomass of 30-40(t/ha)level decreased significantly in 2004,and the basic changes were 1-10 and 10-20(t/ha).And the ratio of 40-50(t/ha)forest biomass area and area ratio greater than 50(t/ha)increased significantly from 2004 to 2014,indicating that the implementation of the policy of returning farmland to forest between 2004 and 2014 Large,and achieved a better forest protection effect.