| Cunninghamia lanceolata as one of the main timber species in subtropical regions, is main plantation tree species in Fujian Province which has the important action for maintaining the ecological balance, the regional carbon cycle and the carbon balance. In this paper, the mature Cunninghamia lanceolata plantation(30 years) of state-owned forest farms Jiangle County of Fujian Province as the research object, the basic data for each standard land was obtained by establishing 16 pieces of standard lands. According to the statistical analysis of basic data and the result of field trip, trees in standard lands were divided into dominant trees, intermediate trees, and suppressed trees by the different growth potential. Based on the measured date, the individual tree DBH growth model for Cunninghamia lanceolata plantation, the individual tree height growth model, biomass estimation model of different organs(trunk, root, leaf, branch), the whole-plant biomass model, and growth equation of 5a were simulated. Based on the model and related carbon storage, carbon storage and carbon fixation of different organs of individual Cunninghamia lanceolata different growth potential were calculated and different organs carbon storage and carbon fixation of individual Cunninghamia lanceolata were compared; five years as a cycle, the total carbon fixation of different growth potential were calculated.The main conclusions were drawn as follows: 1 The construction of the optimal DBH growth model and the tree height growth model.Four growth curve models(Richards, Logistic, single molecule type curves, strictsumach) selected by For Stat were simulated. The fitting effect of Logistic is the worse; the fitting effect of Richards, single molecule type curves and strictsumach are good. The growth curve was suitable for the growth characteristics of DBH and tree height. According to R2, the scatter distribution and curve characteristics, the best curve-fitted equation for the growth of DBH and tree height was selected. 2 The establishment and optimization of biomass forecast model and plant biomassBiomass equation was simulated by Logistic equation and power function which are suitable for the biological characteristics. According to different growth potential biomass and D, DH as independent variables, the Logistic equation and power function of different organs(trunk, root, leaf, branch) and whole-plant were simulated. The determination coefficient R2 of the model was between 0.881 to 0.932.Based on Residual Sum of Squares, Total Average Relative Error, Average Relative Error, Average Absolute Relative Error, Akaike Information Criterion and Bayesian Information Criterion, the best modle was selected from four modles. The best modle included 12 power function models(DH as independent variables), 8 Logistic models, and 14 independent variables.The proportion order of different organ biomass in whole forest biomass was tree > branches > roots > leaves. The individual biomass of different growth potential was in the sequence of dominant trees > average trees >intermediate trees > suppressed trees. 3 Individual carbon storage, annual carbon fixation, average carbon fixationIndividual carbon storage of dominant trees was 219.13 kg C·N-1, the peak of annual carbon fixation was at age of 17 years(6.86 kg C·N-1·a-1), the peak of average carbon fixation was at age of 30 years(5.14 kg C·N-1·a-1). Individual carbon storage of intermediate trees was 84.41 kg C·N-1, the peak of annual carbon fixation was at age of 11 years(3.24 kg C·N-1·a-1), the peak of average carbon fixation was at age of 20 years(2.27 kg C·N-1·a-1). Individual carbon storage of dominant trees was 35.13 kg C·N-1, the peak of annual carbon fixation was at age of 9 years(1.8 kg C·N-1·a-1), the peak of average carbon fixation was at age of 16 years(1.22 kg C·N-1·a-1). Individual carbon storage of average trees was 114.31 kg C·N-1, the peak of annual carbon fixation was at age of 17 years(3.97 kg C·N-1·a-1), the peak of average carbon fixation was at age of 30 years(2.84 kg C·N-1·a-1).In conclusion, individual carbon storage was in the sequence of dominant trees > average trees >intermediate trees > suppressed trees. Average carbon fixation ability was in the sequence of dominant trees > average trees >intermediate trees > suppressed trees. Annual carbon fixation was in the sequence of dominant trees > average trees >intermediate trees > suppressed trees. 4. The whole forest biomass and 5 years’ biomassThe biomass of mature-plantation was 158.83 t·hm-2, the 5 years biomass of mature-plantation was 44.82 kg·5a-1·hm-2 and the increasing rate of biomass was 39.31 % respectively. 5 The whole forest carbon storage and 5 years’ carbon fixationThe carbon storage of mature-plantation was 79.83 t·hm-2 and the 5 years’ carbon storage of mature-plantation was 22.53 kg C·5a-1·hm-2.5 years’ carbon fixation of dominant, intermediate and suppressed trees was 9.33 kg C·5a-1·hm-2, 12.73 kg C·5a-1·hm-2, 0.98 kg C·5a-1·hm-2 respectively in mature-plantation; the ability of carbon fixation was in the sequence of intermediate trees > dominant trees > suppressed trees. |
PDF Full Text Request