Study On Three Kinds Of Density Of Cryptomeria Fortunei Plantation Growth And Economic Benefits Comparison

As one of the main timber species of Cryptomeria fortunei area in South Asia, because of its strong adaptability, cold and drought resistance, fast growth characteristics, widely cultivated in Guangxi area and high elevation area. The research of Guangxi state owned forest farm in the sixty thousand 31 year old Cryptomeria fortunei plantation of different density as the research object of study, which set the density:high density (2850 plants hm-2), low density (2075 plants hm-2), low density (1628 plants hm-2) as the research object, to explore the optimal density of Cryptomeria fortunei plantation growth benefit, provide scientific theoretical basis for Cryptomeria fortunei forest cultivation and planting, through investigation statistics on 31a three density of Cryptomeria fortunei plantation, analysis the different law of stand growth and biomass, productivity level, using static and dynamic indicators of economic benefit evaluation for Cryptomeria fortunei with different density, comprehensive evaluation of planting density of Cryptomeria fortunei quality, for the tree species To provide a scientific basis for the promotion of forest. The results showed that:1,Reach breast height Kolff in low lower than 1, using stem analysis method of three kinds of density of Cryptomeria japonica plantation of tree height, DBH and individual volume growth index evaluation, concluded that the high density of trees DBH, individual volume growth in the overall level of tree density and low density of tree height growth trend of higher density, density. Combined with the nonlinear statistical models of three kinds of density of Cryptomeria fortunei plantation growth index regression analysis, low density of trees of tree height, individual volume and low density of DBH model fitting model has the highest accuracy, R2 reached 0.97, high density and low density of tree height, individual volume of fitting model to Richard model has the highest accuracy, the R2 of 0.98 above.2, In the biomass, productivity research, the overall level of low-density plantation biomass higher than high density, density plantations, but low density plantation Gancai biomass higher than high density plantation. But the high density of litter biomass is much higher than that of the medium density and low-density plantation. In comparison of biomass, low density plantation in various organs of the productivity were higher than high and medium density.3, Three kinds of artificial forest economic benefit analysis to dynamic and static index launched evaluated, and the results indicated that, the low density plantation 31a investment profit is higher than that of high density plantation, low density plantation in average profit to investment rate is also high ratio of density of artificial Lin high. Low density plantation financial internal return rate (12.74%) was higher than that of high density forest (12%), density plantations financial internal return rate (12.22%) is higher than that of the high density forest (12%). On the three density plantation business model, low stand density can be planted in application.