Community Dynamics of Arbor Layer in the Mixed Evergreen and Deciduous Broad-Leaved Forests during 1996-2012 in Tianmu Mountain

[Objective]Using long-term exploration of community dynamics( ranging from 1996 to 2012),this study was aimed to provide scientific support for forest protection,management and operation in Tianmu Mountain. [Method]In1996,a field site with the size of 1hm~2 locating in evergreen and deciduous broad-leaved mixed forest of Tianmu Mountain,a national nature reserve in Zhejiang province was built,and then each tree in the site was numbered,labeled and recorded it's species name,height,diameter at breast height( DBH),location and other information. In 2012,the above data was determined again to compare the community dynamics of the trees with the DBH more than 10 cm during the past 16 years. [Result]The results showed that in 1996,the evergreen broad-leaved trees and deciduous broad-leaved trees accounted for 54. 97% and 45. 03% of the total number of trees,respectively,while in 2012,the ratios changed to62. 81% and 37. 19% respectively. The community structure changed from 40 species,34 genera and 24 families in