Abstract:

Based on the sample plot data from the forest resources inventory of Ganzhou City,the carbon density of Pinus massoniana forest was calculated by regional scale carbon budget model (CBM-CFS3),and the spatial distribution and influencing factors of carbon density were analyzed by geostatistics and multiple stepwise regression methods,respectively. The results showed that there were differences in the optimal stand age-accumulation equation for different forest types and origins of Pinus massoniana forests. In general,the Logistic model,Richards model and Gompertz model fit better than the Korf model. The total carbon density of the stand was 135.08MgC/hm²,in which the carbon densities of the vegetation layer carbon pool and the dead organic matter (DOM) carbon pool were 41.51MgC/hm² and 93.57MgC/hm²,respectively. The vegetation layer carbon pool showed as trunk>branches>roots>leaves while DOM carbon pool showed as soil layer>litter>dead wood. The total carbon density of forest stands had a certain positive correlation in space,mainly concentrated in 106.73-161.16MgC/hm². The area of the low-value carbon density area was larger than the high-value carbon density area,but there was no obvious regularity in space. Age group,average diameter at the breast height (DBH),canopy density and annual mean temperature were all highly significantly and positively correlated with the total carbon density of forest stands (P<0.01),so they were the main factors affecting carbon density. The growth model constructed by the sample plot data from the forest resources inventory was used to estimate forest carbon density in the CBM-CFS3 model,which was conducive to get a more comprehensive and accurate estimation of different carbon pools in regional forests. The vegetation factor was the main factor affecting its carbon density.

Key words: Pinus massoniana forest, forest carbon density, CBM-CFS3 model, influencing factors;southern Jiangxi Province