封育年限对毛竹林群落结构和林下植物多样性的影响

Effects of exclosure term on community structure and undergrowth diversity of Phyllostachys pubescens

为探讨自然封育对毛竹林群落结构和林下植物多样性的影响,采用空间代替时间的方法,以浙江省杭州市余杭区常规经营(0年)和不同封育年限(10,20,30年)的毛竹林为对象,对毛竹林分结构和林下植物多样性进行了全面研究。结果表明:随着封育年限的延长,竹林密度增大,胸径变小;封育毛竹林中2度以上活立竹的密度显著高于常规经营(P<0.05),枯立竹的密度随着封育年限的延长而显著增加(P<0.05);封育20年后的2度以上活立竹和枯立竹的胸径显著减小(P<0.05)。封育0,10,20,30年的毛竹林下灌木种类分别为68,35,58,77种,而草本植物种类则分别为64,23,31,44种。封育10年的林下灌木的Simpson指数显著低于其他林分(P<0.05),封育20年后的Shannon-Wiener指数显著高于前期年份(P<0.05),封育显著提高了Pielou指数(P<0.05);封育显著降低了草本植物的Simpson指数(P<0.05),常规经营林下草本多样性指数Shannon-Wiener显著高于封育20年后的林分(P<0.05),封育10年的林下草本均匀度指数Pielou显著高于其他林分(P<0.05)。

To explore the effects of natural exclosure on the community structure of the moso bamboo forest and the diversity of understory plants, two types of moso bamboo forest(human-manage forest and natural exclosure forest) were chosen in Yuhang District, Hangzhou City, using the method of space-for-time. In this study, 4 different plots(0 years, 10 years, 20 years, and 30 years) were set up, according to the age of natural exclosure. The culm density, diameter at breast height(DBH), and understory vegetation types etc. were investigated in the field survey. The results indicated that the culm density of bamboos increased gradually with increase of exclosure age, while the average DBH of bamboo decreased significantly. The density of≥2° bamboo of natural-exclosure moso bamboo forest was significantly higher than that of the intensive-managed forest(P<0.05). The density of dead bamboo increased significantly with the extension of exclosure period(P<0.05). The DBH of≥2° old bamboo and dead bamboo started to decrease significantly after 20 years of natural exclosure. The species of shrubs under the moso bamboo forest with 0, 10, 20, and 30 years of natural exclosure were 68, 35, 58, 77, respectively, while the herbaceous species were 64, 23, 31, and 44, respectively. The Simpson index of shrubs with 10 years of natural exclosure was significantly lower than that of other years(P<0.05). The Shannon-Wiener index after 20 years was significantly higher than that of the early year(P<0.05). The natural exclosure can help to increase the index of Pielou(P<0.05). The Simpson index of the herbaceous plants decreased in the natural exclosure forest(P<0.05). The Shannon-Wiener index of intensive-managed forest was significantly higher than that of 20 years(P<0.05), and the Pielou index of 10 years was significantly higher than the other years(P< 0.05).