天目山常绿阔叶林的混交度研究

在天目山国家级自然保护区内选择典型常绿阔叶林，设置100m×100m样地，用全站仪测定每株树木坐标。选择胸径在5cm以上的乔木，用优势度分析法确定群落优势种，八邻域边缘校正法校正，并采用树种多样性混交度进行计算。结果表明，天目山常绿阔叶林优势种群以细叶青冈Cyclobalanopsis gracilis，青冈Cyclobalanopsis glauca和短尾柯Lithocarpus brevicaudatus为主，形成多优势种结构特征，样地平均混交度为0．5051，优势种群中常绿树种的混交度为0．4836，非常绿树种的混交度为0．5823。研宄认为，天目山常绿阔叶林保持了较高的树种多样性；细叶青冈、青冈和短尾柯等优势种群因兼有实生和萌生2种聚集繁殖方式所致，降低了常绿阔叶林的混交度；树种混交度是随着胸径的增大而增大的；常绿阔叶林总体呈中度混交状况。图5表1参12

The mingling index with evergreen broadleaf forests on Mount Tianmu

Mingling of dominant plant populations in an evergreen broadleaf forest, one of the most important plant types in the Mount Tianmu National Nature Reserve of Zhejiang Province, were studied to supply a theoretical basis for evergreen broadleaf forest protection, restoration, and reconstruction. A typical plot in the reserve, 100 m × 100 m, was surveyed for tree diameter at breast height （DBH） above 5 cm with Total Station （Leica TCR702Xrange） equipmentused to measure tree coordinates. Also, dominant plant populations were determined using the Dominance Index with edge correction applied and the mingling index calculated for tree species diversity. Results showed that the dominant plant populations of evergreen broadleaf tree species （Cyclobalanopsis gracilis, Cyclobalanopsis glauca, and Lithocarpus brevicaudatus） exhibited diverse and dominant species characteristics. The average mingling index for the plots was 0. 505 1 ; while the evergreen broadleaf tree species mingling index was 0. 483 6, and the non-evergreen broadleaf species mingling index was 0. 582 3. Overall, these tree species maintained the evergreen broadleaf forest biodiversity. In addition, as dbh increased, the mingling index increased. Since C. gracilis, C. glauca, and L. brevicaudatus predominantly reproduced through sprouting, the mingling index was low. This study evergreen broadleaf tree species showed moderate mixing. Ch, 5 fig. 1 tab. 12 ref. ]