[Early effects of forest harvesting gap on understory plant diversity of three different plantations in Baiyun Mountain, China.]

Pinus massoniana, Cunninghamia lanceolata, and Phyllostachys edulis are the main afforesting species in the low hilly areas and valley of the southern Yangtze River for commercial purpose. Ecological problems such as the monotonous community structure and low biodiversity are common in these plantations. To understand the effect of forest harvesting gap on the understory plant diversity in the three plantations, different size gaps with identical habitats were conducted with cano-pies as control in the three plantations in Baiyun Mountain. The life form spectrum of plants and plant diversity were compared among the different forest gaps. The results showed that species richness was the highest in C. lanceolata plantation (57 species), followed by P. edulis plantation (53 species) and P. massoniana plantation (41 species) in two years after harvesting. In the early period, plant species were more abundant in the gaps than that in the controls in C. lanceolata and P. edulis plantations, but there was no significant difference between the gaps and the control in P. masso-niana plantation. The percentage of phanerophyte plants were significantly higher in the forest gaps covered 500 m马尾松、杉木和毛竹是长江流域低山丘陵地区的主要用材树种,其人工林群落结构简单和生物多样性低下是普遍存在的生态学问题.为了解采伐林窗对3种人工林林下植物多样性的影响,选择生境条件基本一致的3种林分,以林下为对照,比较了通过采伐获得的不同大小林窗间植物生活型构成和多样性差异.结果表明: 采伐林窗后2年,3种林分中杉木林的植物种类最多,达57种,其次是毛竹林(53种)和马尾松林(41种).在采伐林窗初期,杉木林和毛竹林林窗内物种数显著高于对照,但马尾松林林窗与对照没有显著差异.500 m