Estimation And Analysis Of Forest Above-ground Carbon Storage Based On Remote Sensing In Huma River Basin

Forest is the major part of terrestrial ecosystems and the largest carbon reservoir on earth.It not only has the function of regulating the regional ecological environment,but also plays an important role in the global carbon balance.The Huma River Basin in the study area is located in the hinterland of the Greater Khingan Mountains permafrost region,which is sensitive to climate change.This study takes the estimation of forest carbon storage as the main goal and takes the Huma River Basin as the research object.First,the image features of the forest vegetation in the study area are extracted using high-resolution Sentinel-2 multispectral remote sensing data,Sentinel-1 SAR data and DEM data.Parameters,combined with the field survey data,based on the random forest algorithm to classify the main dominant tree species in the study area.Subsequently,through the extraction of remote sensing images and analysis of the correlation between the relevant modeling factors and the carbon storage of the measured sample plots,three regression models of OLS,GWR and GWRK were constructed to estimate and predict the forest carbon storage of different dominant tree species in the study area.Finally,the estimation accuracy of different models was compared and analyzed,the best model was selected and the tree species classification results were used to estimate the forest aboveground carbon storage in the study area,and the spatial distribution characteristics of the forest aboveground carbon storage in the study area were analyzed and discussed.Research indicates:(1)Based on remote sensing images and measured data,the overall accuracy of the classification of the main dominant tree species in the study area using the random forest algorithm is 88.16%,and the Kappa coefficient is 0.83.The classification effect is relatively ideal,which can effectively describe the forest distribution in the Huma River Basin.The classification results show that the dominant tree species of the forest type in the study area is mainly Larix gmelinii,accounting for 57.26%of the total forest area,followed by Betula platyphylla and Pinus sylvestris var.mongolica,and the mixed forest is the least distributed.(2)Three regression models,OLS,GWR and GWRK,were used to predict the aboveground carbon storage of different dominant tree species in the study area.The results of the model accuracy test show that the estimated results of the GWRK model are more consistent with the actual situation,and the accuracy is higher,which is better than the other two methods.(3)The total aboveground carbon storage of forests in the Huma River Basin is 97.02Tg,and the carbon storage order of the dominant tree species is Larix gmelinii(49.59Tg)>Betula platyphylla(35.88 Tg)>Pinus sylvestris var.mongolica(7.27 Tg)>Mixed Forest(4.28 Tg).This is not only affected by the differences in the carbon sequestration capacity of different tree species,but also has a lot to do with the distribution area of each dominant tree species.(4)The analysis of the spatial distribution characteristics of forestry aboveground carbon storage in the Huma River Basin shows that:in the horizontal direction,the forest carbon storage in the Huma River Basin is concentrated in the density area of 15-50 t/hm~2.In the vertical direction,the forest vegetation at an altitude of 500-800 m has the largest carbon storage and the strongest carbon sequestration capacity.Forest carbon storage is concentrated in areas with slopes between 0°and 25°,and forest carbon density is not significantly affected by slope.At the same time,there is no obvious difference in the carbon density of forest vegetation across aspests,and the carbon storage(53.94%)of the shady and semi-shady slopes is slightly higher than that of the sunny and semi-sunny slopes.