Investigation on Carbon Sequestration Capacity of Typical Subtropical Evergreen Broad-leaved Forest in Jiulianshan Nature Reserve

Abstract

Nine investigation sample plots (each 20m×20m) were set up to investigate the biomass and soil bulk density of three typical subtropical evergreen broad-leaved forests (Castanopsis eyrei, Schima superba, Cyclobalanopsis glauca) in Jiulianshan National Nature Reserve in Jiangxi Province in 2015 and 2020. The vegetation carbon density and carbon storage, soil carbon density and carbon storage, the carbon density and carbon storage of the investigation sample plots were calculated according to the organic carbon content of vegetation and soil. In addition, the changes in carbon sequestration capacity of three typical subtropical evergreen broad-leaved forests in Jiulianshan National Nature Reserve in Jiangxi Province in 2015 and 2020 were analyzed. The investigation results had shown that:Compared with 2015, the average organic carbon content of Castanopsis eyrei, Cyclobalanopsis glauca, and Schima superba of Jiulianshan National Nature Reserve in Jiangxi Province increased by 10.36%, 10.13% and 7.73% in 2020. The average organic carbon content of leaf, branch, stem and root increased also by 10.60%, 10.38%, 11.13% and 5.29% respectively. The soil organic carbon content of different soil layers in 2020 and 2015 were all decrease with the increase of soil depth. Compared to 2015, the organic carbon content increased while the soil bulk density decreased in 2020.The average carbon density of the forest vegetation layer in the investigation plots of Jiulianshan National Nature Reserve in Jiangxi Province had increased from 82.63t/hm2 in 2015 to 108.94t/hm2 in 2020. The carbon density of the arbor layer had increased from 76.11t/hm2 in 2015 to 106.09t/hm2 in 2020, while the carbon density of the shrub layer, herbaceous layer and litter layer in 2020 was lower than that in 2015. In 2015 and 2020, the carbon density of different vegetation layers in the three typical subtropical evergreen broad-leaved forest of Castanopsis eyrei, Schima superba and Cyclobalanopsis glauca were all ranked as arbor layer, shrub layer, litter layer and herbaceous layer.The average soil carbon density (calculated by 10cm) at different depths in 2020 and 2015 in Jiulianshan National Nature Reserve of Jiangxi Province all decreased with the increase of the soil depth. The total average soil carbon density in 2020 was 168.03t/hm2, which was 35.4%% lower than that of 2015(288.05t/hm2).The average carbon storage in the sample plot (20m×20m) in Jiulianshan National Nature Reserve in Jiangxi Province decreased from 13771.04kg in 2015 to 10688.11kg in 2020 with a decrease of 22.38%. The average carbon storage of vegetation decreased from 3305.20kg in 2015 increased to 4357.60kg in 2020 with an increase of 31.8%, while the average soil carbon storage decreased from 10137.04kg in 2015 to 6475.51kg in 2020 whit a decrease of 36.1%.