Distribution Characteristic And Individual Forest Tree Growth Analysis Of Picea Likiangensis In Changdu Of Tibet

Picea likiangensis var. balfou riana is a tree species widely distributed in southwest China. They form a intermittent distribution forest community in the upper parts of subhumid and humid subalpine regions with their adaptability of cold and dry. Their main distribution in Northwest Yunnan, Southwest Sichuan，South Qinghai and Southeast Tibet. Changdu t is the second largest forest region in Tibet. Changdu forestry development, is not only related to the Tibet’s economic development and social stability, but also to maintain in Southwest China and Southeast Asia region and has an irreplaceable effect on the world’s ecological balance. Study the existing forest distribution and growth rule in the area, to provide the theory basis for existing natural forest and the plantation forest ecological system restoration and sustainable management.This study summarized and analyzed the existing forest inventory data and analytical wood material in Changdu, Tibet. Studied the spatial pattern and relationships between DBH(diameter at breast height), tree height and volume and altitude, slope and soil. Explored the growth rules of tree height, DBH and volume. Identified the optimal growth model for tree height, DBH and volume. Drew tree height, DBH and volume growth and average years of growth curve and analyzed the growing process. The results show that:(1) Picea likiangensis var. balfou riuna mainly distributed in the elevation of3500to4500m and the grade of20to50°. In the aspect of southeast, it was the most distribution. And in the middle slope position, it was the most distribution, too.The more the soil thickness, the more the distribution of Picea likiangensis var. balfou riana。 And it mainly distributed above60cm soil.(2) The spacial distribution pattern (elevations, slope grade, slope aspects and positions) of Picea likiangensis had a significant difference among tree height, DBH, volume. The difference of different terrain factors, may cause stand density, temperature, moisture and human interference degree are different. thus cause spruce trees has different distribution.(3) Diameter at breast height growth model:Yd=75.571(1-1.02le-0.005T)0973，R2=0.866**Height growth model: Y(?)=31.382(1-0.979e-0019T)2.170，R2=0.992**. Volume growth model: (4) The growth models could fit its growth regularity precisely. Obvious trend of Picea likiangensis var. balfou riana DBH increase with age, older than160years later, the DBH was continued growth; high growth had a "S" shaped, and the height of160-year up to nearly30m. the growth process of volume differed from the DBH and tree height. In the160years. it showed a "J" shaped, that was, the volume slowly grown in the early of the growth of trees (<40years) and more quickly after40years. The current annual increment of DBH increased apparently at the year of30, and reached at its highest point at45. While, when it comes to the height, the highest value of current annual increment and average increment approximately20years after that of DBH. Among the growth regularity of volume, the average increment and current annual increment still hold a rising trend. In view of the quality mature age is relative appear later, consequently, management like thinning measures should be implemented in order to enhance the net primary productivity of the Picea likiangensis forest.