Biomass And Growth Rule Of The Pinus Yunnanensis Var. Tenuifolia Plantaion

Pinus yunnanensis var. tenuifolia has been planted widely in southwest of China as one of important timber species. Along with the Guangxi forestry strategy adjustment, more fine tree species will be promoted, compare with the Pinus massoniana, the P. yunnanensis var. tenuifolia with drought tolerance, fast growth, high yield and other characteristics. This paper studied the biomass, the productivity and the growth rule of P. yunnanensis var. tenuifolia plantation in Yachang State Forest Farm which lacated in Guangxi province. The results were as follows:(1) The average age of the P. yunnanensis var. tenuifolia plantations in the Yachang forest farm was 28a, the total biomass of P. yunnanensis var. tenuifolia plantation was 482.26 t·hm-2, in which the arborescent stratum was 461.95 t·hm-2 (95.79%). Biomass allocation patterns of the P. yunnanensis var. tenuifolia organs were:trunk>branches>rhizome>bark>leaves>thick roots >middle-size roots>rootlets, in which the trunk and the branches biomass were 243.36 t·hm-2 and 97.46 t·hm-2, total occupied 73.78% of the arborescent stratum’s (only P. yunnanensis var. tenuifolia) biomass. The diameter class distribution of P. yunnanensis var. tenuifolia forest presented the normal distribution approximately. The total productivity of 28a P. yunnanensis var. tenuifolia plantation was 23.52 t·hm-2·a-1, in which arborescent stratum was 22.4 t·hm-2·a-1.(2) Average DBH (diameter at breast height) of 28a Pinus yunnanensis var. tenuifolia plantation was 27.35cm, average height of tree (H) was 18.42m, and average timber volume (V) was 0.4430m3. This rapid growth period were in 0a～11a as a whole, 11a～22a years were the steady vegetal periods, the years after 22a will be the slow vegetal period. When it was 28a, the mass-accretion had still not achieved the quantity mature age. Through curve fitting with the different growth models, we finally got the R2 reached above 0.99, the fitting is fine. The most superior model to fit the DBH, H, and V were the Richard model, the Weibull model, and the Comperz model, respectively.This article findings have surveyed the Pinus yunnanensis var. tenuifolia forest biomass and simulate its growth rule, has made the key elaboration regarding in the biomass assignment and growth process each stage, regarding understood the Pinus yunnanensis var. tenuifolia forest the biomass accumulates with the environment and the cultivation measure relations has certain help.