重庆市主城区不同林地类型群落结构的比较研究

A Comparative Study of the Structure Characteristics of Different Forest Types in the Main Urban Zone of Chongqing

调查了3种不同人为干扰程度的林地类型，分析比较了其乔木层优势度、优势种数目，木本植物的物种多样性、物种丰富度和大小结构等群落学指标．结果表明：（1）乔木层优势度指数及木本植物物种多样性大小顺序依次为自然林〉半自然林〉人工林，而优势种数目则反之．与自然林相比较，主城区中人工林地的木本植物物种多样性较低，但优势种数目较大，集中程度较低．（2）乔木层地上生物量和胸高断面积大小顺序分别为自然林〉半自然林〉人工林，半自然林〉自然林〉人工林．与自然林相比较，主城区中人工林乔木层的胸高断面积、生物量较低，分别只有自然林、半自然林的22．8％～57．5％，36．4％～69．7％．（3）木本植物高度等级和乔木层胸径等级中自然林在各个等级皆有分布，总体上呈正金字塔形．与自然林相比较，主城区林地型绿地中木本植物大小结构分布较为集中，树高多为1～2m，胸径集中在7．5～20cm．并在此基础上探讨了在重庆主城区营建人工林时应注意的一些群落学问题．

From the point of synecology, 3 different forest types of human-caused disturbance were investigated. Some indices （dominance index of arborous layer, species diversity, species richness index, composition characteristics of life-form and others） were compared and analyzed. The results were as follows： （1） For dominance index, species diversity and species richness index, natural forests ranked first, followed in sequence by half-natural forests and man-made forest, but the number of dominant species presen- ted an opposite order. （2） For the indices of stand biomass and DBH area of arborous layer, the sequence was natural forests 〉 semi-natural forests 〉 man-made forest and semi-natural forests, natural forests and man-made forests. （3） In the height and DBH class of woody plant, the woody individuals distribution assumed a totally pyramidal shape in natural forests. In contrast with the natural forests, the characteristics of man-made forests were found in the main urban zone of Chongqing. The distribution range of size class structure was narrow, tree height being mostly 1-2 m and DBH 7.5-20 cm. Based on the results achieved, the basic synecological principles are discussed for woody plant construction of man-made forests in Chongqing.