Study On The Potential For Carbon Sequestration Of Artificial PR107Forest Ecosystem In Rubber Tree Planting Area Of Qiongzhong Of Hainan

The international community has reached general agreements on relieving climate change by afforestation and reforestation. The tropical zones in China are priority areas for afforestation and reforestation. However, in these areas, people have paid too much attention to the profit of the rubber latex and timber while paying little attention to the study and quantitative evaluation of the carbon sequestration capacity. In particular, little has been known about this capacity of the whole ecosystem. This paper takes Qiong zhong rubber planting area in Hainan as the research sites, with actual measurement of the sample plots combined. The carbon sequestration capacity of PR107artificial rubber plantation ecosystem of this rubber planting area was discussed. The main research results were as follows:(1) To avoid the effect of tree height error on biomass model, nonlinear power equation of the PR107artificial rubber plantation biomass was fit, regarding DBH (diameter at breast height) of tree as the single variable. Growth curve of PR107artificial rubber plantation in Qiongzhong rubber planting area of Hainan was obtained by fitting to logistic growth model.(2) PR107artificial rubber plantation ecosystem in Qiongzhong rubber planting area of Hainan has a relative high carbon sequestration capacity, whose above-ground part and underground part are of relative high carbon intensity.(3) The soil organic carbon reserves of PR107artificial rubber plantation ecosystem in Qiongzhong rubber planting area of Hainan are basically concentrated in surface soil (0～20cm), which increase as soil depths increase in vertical distribution. The soil organic carbon content of the same age presents the regularity of decreasing with the increase in soil depth, among which the soil organic carbon content variation of shallow layer and deep soil are especially great.(4) Annual carbon return of artificial rubber plantation litter of each tree-age are2.41t·hm-2,2.48t·hm-2,2.85t·hm-2,3.56t·hm-2and3.79t·hm-2. Carbon return of litter increases with the increase of the tree-age. Annual carbon release amount of each tree-age are0.12t·hm-2,0.21t·hm-2,0.27t·hm-2,0.19t·hm-2and0.27t·hm-2respectively. Carbon release amount of litter basically shows a tendency of increasing as the tree-age increases.(5)The carbon stocks of PR107artificial rubber plantation ecosystem in Qiongzhong rubber planting area of Hainan basically consist of arborous layer, shrub layer and herbaceous layer. The carbon stock of PR107artificial rubber plantation of24a tree-age is276.77t·hm-2, in which the carbon stock of the arborous layer accounts for63.64%of the whole vegetation and shrub layer, while herbaceous layer and litter layer all account for1.06%of the whole vegetation. Soil carbon reserves and rubber latex carbon reserves occupy20.90%and5.30%respectively. The annual fixation of PR107artificial rubber plantation ecosystem of24-year-old life cycle of is11.53t·hm-2·a-1(6) Soil respiration rates of PR107artificial rubber plantation ecosystem take on significant spatial changing dynamics. Different treatments also present similar curve changing contours. The maximum value of soil respiration rates appears at tree-age19a, while the minimum value is at24a. Among the same tree-age and different carbon source input, the treatment of doubling litters enables soil respiration rate of each tree-age exceed other treatments. Removing litters gets the lowest soil respiration rate.(7) Soil respiration rates are significantly associated with soil temperatures (P<0.05), but they are not significant correlated with humidity (P>0.05).