Research In Forest Growth And Economic Benefit Comparison Of Castanopsis Kawakamii And Quercus Acutissima Plantation

The precious local tree species have been rapidly developed in the recent decades because of the increasing market demand of their timber in the social world. Castanopsis kawakamii Hayata and Quercus acutissima Carruth are both precious local tree species of Fagaceae in Guangxi, they are planted as timber tree species, having many good characteristics, such as tall and straight trunk, good stem form, high quality timber, and so on. Nowadays, there are deficiencies exist in the research and development of the two kinds of timber plantations at home and abroad, thus this study has conducted tree measurement survey in sample plots, evaluated the quadrat biomass and the ecological environment factors of the two timber plantations, which were both27years old. At the same time, in order to provide some references for the scientific assessment and project investment decision of the two plantations, whose forest ecological benefit, economic benefit and comprehensive benefit have been comprehensively evaluated by mathematical model in growth process, hierarchical analysis method, and so on. The results are as follow:1. Using stem analytic method to research the growth role of two Fagaceae species, Castanopsis kawakamii Hayata and Quercus acutissima Carruth. As the results, we found both diameter at breast height (DBH) and individual volume growth trend of Castanopsis kawakamii Hayata plantation were higher than that of Quercus acutissima Carruth plantation in the overall level. However, the height growth trend of Quercus acutissima Carruth was better than Castanopsis kawakamii Hayata’s. The results of growth model fitting indicated that the optimum growth model of Castanopsis kawakamii Hayata’s height, individual volume and Quercus acutissima Carruth’s DHB was Kolff model while the optimum growth model of Castanopsis kawakamii Hayata’s DBH and Quercus acutissima Carruth’s height, individual volume was Richard model.2.In the study of biomass, productivity, the overall level of Castanopsis kawakamii plantation biomass was higher than that of Quercus acutissima plantations, but the Quercus acutissima forest dry biomass was higher than that of Castanopsis kawakamii plantation. In biomass comparison of evergreen and deciduous tree species, Quercus acutissima, leaf net productivity is higher, the Quercus acutissima forest productivity than Castanopsis kawakamii plantation.3.In the two forest carbon storage allocation pattern research, two forest carbon storage space distribution sequences are tree layer>litter layer>herb>shrub layer.27years of Castanopsis kawakamii artificial Lin Qiaomu layer carbon storage is128.21t/hm2, accounted for the entire layer of vegetation carbon storage in96.93%. More than27years of total carbon storage in Quercus acutissima forest ecosystem46.421t/hm2. Castanopsis kawakamii plantation carbon fixation ability. And in comparison to the plantation on soil physical and chemical properties, Castanopsis kawakamii plantation because of Quercus acutissima plantations.4. Using the static and dynamic analysis, with the same plantation operational cost, return on investment of27a Quercus acutissima Carruth plantation was higher than that of Castanopsis kawakamii Hayata plantation, and the annual average investment yield of Quercus acutissima Carruth plantation was also higher than Castanopsis kawakamii Hayata’s. Financial internal rate of return (12.74%) of Quercus acutissima Carruth plantation was higher than that of Castanopsis kawakamii Hayata (12%). Result of sequence benefit analysis showed that the optimal rotation cutting period of Quercus acutissima Carruth was20a after planting, while the Castanopsis kawakamii Hayata was22a.