广州城市森林林分结构及林下植物多样性研究

Study on Stand Structure and Undergrowth Species Diversity of Urban Forest in Guangzhou

以广州市城市森林为研究对象，在天然次生林、改造人工林和未改造人工林设置大样地进行调查，比较分析3种森林类型的林分结构特征和林下植物多样性。结果表明，天然次生林乔木层主要树种为华润楠、罗浮柿、木荷、红花荷、马尾松、鼠刺等，改造人工林主要有马尾松、杉木等造林树种与其他引进树种，未改造人工林主要有湿地松；天然次生林大径木和特大径木株数比例较高，改造人工林中小径木较多，未改造人工林径阶－株数曲线表现为双峰状正态分布；天然次生林树高分布在10～14 m的植株较多，改造人工林树高近似于正态分布，未改造人工林树高结构呈现为接近该林分平均高的植株数最多的非对称性山状曲线；天然次生林林下植物多样性最高，改造人工林次之，未改造人工林最小。

Urban forest is an important part of forest resources of China,and it played an important role in economy,ecology,society and so on.A study on urban forest of Guangzhou was made in this paper.Plots were set up in the natural secondary forest,improved plantation and unimproved plantation,the stand structure characteris-tics and species diversity of undergrowth of the three different forest types were comparatively analyzed.The results showed that the arbor layer of the natural secondary forest in Guangzhou mainly consisted of Machilus chinensis,Di-ospyros morrisiana,Schima superba,Rhodoleia championii,Pinus massoniana,Itea chinensis and so on.The im-proved plantation was mainly composed of Pinus massoniana,Cunninghamia lanceolata and other introduced tree species.The main tree species of the unimproved plantation was Pinus elliottii.The number proportion of the trees with large DBH was higher in the naturally secondary forest while the trees with middle to small DBH accounted for large proportion in the improved plantation,whereas the DBH-number curve of the unimproved plantation showed normal distribution with double peaks.More trees with height between 10 m to 14 m mainly distributed in the natu-rally secondary forest,the improved plantation approximately to normal distribution.The tree height structure of the unimproved plantation presented as asymmetric mount-formed curve close to the average height of the majority trees.The species diversity of undergrowth in the naturally secondary forest was the highest,which was followed by that of the improved and unimproved plantation.