中文摘要：

为揭示不同发育阶段杉木人工林林下植被多样性的变化规律,对福建三明莘口教学林场不同发育阶段杉木人工林（幼龄林、成龄林和过熟林）林下植被的种类、数量、丰富度、盖度、高度等指标进行调查。结果表明：不同发育阶段杉木人工林林下植被物种丰富度（S）差异不大,个体丰富度（N）差异较大,表现为成龄林（478个）〉过熟林（308个）〉幼龄林（223个）;幼龄林林下植被以玉叶金花等耐阴树种占优势,成龄林及过熟林中网脉酸藤子、毛冬青等喜阳植物重要地位明显上升,在各发育阶段均处于优势地位的物种如裸花紫珠、杜茎山、狗脊蕨、江南卷柏等,可以考虑作为恢复林分物种多样性的启动物种;随着林分的发育,林下植被Simpson指数（D）、Shannon-Wiener指数（H）、Pielou均匀度指数（J＇）和生态优势度指数（DMc）均表现为先升高后降低的趋势。可见林下植被的物种多样性与杉木林分的生长发育阶段密切相关,及时进行抚育间伐是提高杉木人工林林下植被物种多样性和维持生态系统稳定性的有效途径。

英文摘要：

In order to explore the regulation of understory community characteristics at different developmental stages of Cunninghamia lanceolata plantations, species, quantities, abundance, coverage, height and basal diameter of understory vegetation at different developmental stages of C. lanceolata plantations were investigated in Xinkou Experiment Forest Farm, Sanming, Fujian Province. Results were showed that there was not significantly different in species richness （S） among different developmental stages plantations, whereas the individual abundance （N） was of significant difference. Mussaenda pubescens Ait.f. and other shade species were preponderant in young plantation. The important position of the heliophilous species such as Embelia rudis Hand. -Mazz., Ilex pubescens Hook. et Am. were rising obviously in mature and overmature forest. The diversity indices of Simpson （D） , Shannon-Wiener （H）, Pielou （J＇） and DMc increased in mature plantation and decreased in over-mature plantation. The understory community characteristics were closely related to the developmental stages of C. lanceolata plantations. It was an effective way to improve the species diversity of undergrowth and maintain the stability of ecosystem by intermediate cutting timely.