紫金山次生林林窗植被和环境的研究

研究了紫金山次生林林窗的形成、分布、植被及环境特征 .林窗主要由人为砍伐马尾松形成 ,呈随机分布 .林窗内共出现木本植物 53种 ,频度最高者为枫香 ,频度 1 0 0 % ,其次为刺楸、白栎、黄连木和栓皮栎 .共出现 1 2 83个体 ,其中枫香占 1 8.7% ,黄檀 1 0 .9% ,白栎 8.7% ,刺楸、栓皮栎分别为 5.5%和 5.3% .林窗的种类密度和个体密度分别为 7种和 1 90株·1 0 0m- 2 .方差分析表明 ,枫香、黄檀、白栎和栓皮栎在林窗内的密度分布与随机分布预测值有显著差异 ,反映其分布的非随机性 .林窗内 ,基周 <2cm的个体占 59.0 % ,树龄愈高 ,个体数愈少 ,基周 4cm时 ,个体数下降 70 .5% ,1 0cm时下降 96.2 % .林窗内光照强度、大气温度、大气湿度及土壤元素分布 ,在时序上有近似与旷地的规律性 ,空间上则显现更复杂的格局 .

Environmental and vegetation studies of the gaps of secondary forests on Zijin Mountain.

This paper studied the development, distribution, vegetation and environment of the gaps of secondary forests on Zijing Mountain. The gaps are mainly produced by logging of Pinus massoniana, and they distribute randomly. 53 woody species are found in the gaps, Liquidambar formosana having the highest frequency (100%),and Kalopanax pictus, Quercus fabri, Pistacia chinensis and Quercus variabilis being very frequent species. 1283 individuals are recorded, of which, 18.75% is Liquidambar formosana, and Dalbergia hupeana, Quercus fabri, Kalopanax pictus and Quercus variabilis are 10.9, 8.7,5.5 and 5.3%, respectively. 7 woody species and 190 individuals per 100 m 2 are found in the gaps. According to variance analysis, the density distributions of major species such as Liquidambar formosana, Dalbergia hupeana, Quercus fabri and Quercus variabilis are significantly different from Poison, showing that their distributions are nonrandom. In the gaps, individuals under 2 cm of basal circumferennce account for 59.0% of the total. The higher the basal circumference, the less the number of individuals. The number of individuals is decreased by 70.5% from 2 cm to 4 cm of basal circumference, and by 96.2% from 2 cm to 10 cm of it. The temporal distributions of light intensity, air humidity and air temperature in the gaps are similar to those on open lands, but their spatial patterns are more complicated.