格氏栲林林窗自然干扰规律

Gap natural disturbance regime in the Castanopsis kawakamii forest

通过对格氏栲 (Castanopsis kawakamii)林林窗自然干扰的基本规律的研究 ,得到了描述林窗干扰状况的一些重要特征。结果表明 :格氏栲林中扩展林窗 (EG)所占面积比例为 34.46% ,而实际林窗 (CG)所占的面积比例为 1 7.81 % ,干扰频率每年分别为 0 .69%和 0 .36% ,林窗干扰返回间隔期为 2 81 a;EG的大小变化为 63～ 1 2 57m2之间 ,平均为 2 4 4 m2 ,而 CG的大小变化为 2 2～ 70 7m2之间 ,平均为 1 2 6m2 ;形成林窗的主要方式是干中折断 ,比例占 36.2 2 % ,其次为枯立 ,比例占 32 .2 8% ;大多数的林窗是由 1～ 5株形成木形成 ,3株形成木形成的林窗最多 ;大多数林窗是在前 50 a形成的 ,其中 1 0～ 40 a之前形成的林窗最多 ;林窗分布格局是均匀分布型的。林窗形成木主要由格氏栲、大叶乌饭 (Vaccinium mandarinorum)、山胡椒(Lindera glauca)、狗骨柴 (Tricalysia dubi)组成。林窗形成木的地径主要集中在 60 cm以下 ,地径 2 0～

This paper, through the study of the gap disturbanc e patterns in the forest, described some important characteristics related to th e disturbance regimes in Castanopsis kawakamii forest The results showed t hat the areas occupied by the expanded gaps (EG) accounted for 34 46% and by th e canopy gaps (CG) accounted for 17 81% of the total land areas in Castanopsi s kawakamii forest. The natural gap disturbance frequencies were 0.69% for EG and 0 36% for CG Per year, respectively, and the recovering i nterval of canopy gaps was about 281 a. Most EG size in Castanopsis kawakamii forest varied from 63 to 1257 m 2 with an average size of 244 m 2. Majori ty CG size in the forest varied from 22 to 707 m 2 with an average size of 126 m 2. The most effective way to form the gap patterns was the breakage of trun k and the standing die, and their proportions for all gapes existed were 36 22% and 32 28%, respectively. Large amount of gaps were formed by 1~5 gap makers, of which three gap maker gaps were the majority. However, most gaps were forme d 50 years ago, and most of which ranged from 10 to 40 years old. The gap distri bution patterns in the forest belonged to the uniform type. Major gap makers in the forest were Castanopsis kawakamii, Vaccinium mandarinorum, Lindera glauca and Tricalysia dubi with diameters below 60 cm. When the gap makers alloc ated in the canopy layer and the ground diameter was about 20~60 cm,the greater probability to make the gaps in the forest occurred.