In this study, Picea schrenkiana var. tianshanica forests in five different longitudinal sites (Zhaosu, Gongliu, Wusu, Urumqi and Hami) in Tianshan Mountains were investigated by using vertical transects. The percentage of trees in different sizes, the diameter classes distribution, and the fitted equations for accumulated stem percentage of P. schrenkiana var.tianshanica were analyzed in order to study the population diameter classes structure. The results showed that the decreasing order for percentage of seedling,sapling and the small trees is Hami, Urumqi, Gongliu, Zhaosu and Wusu.The distribution of stem abundance along the diameter classes in Zhaosu, Gongliu, Wusu, Urumqi and Hami all had an inversed "J" shape. The best fitted equation in Zhaosu and Urumqi for accumulated stem percentage of P. schrenkiana var.tianshanica was exponential,while the best one for another three sites was logarithmic.Gongliu preserves the best natural populations of P. schrenkiana var. tianshanica in terms of various size class analysis indexes.

［目的］ 通过对海南霸王岭林区的热带天然次生林抚育技术试验，了解抚育对次生林群落组成和结构的影响。［方法］ 通过对30个热带天然次生中龄林（60年）固定样地（50 m×50 m）进行抚育前后的森林调查数据，利用配对t检验、非维度多尺度标定（NMS）和指示种分析等统计方法，比较个体数量、物种多样性、群落物种组成、指示种、优势种和群落径级结构在抚育后的变化特征。［结果］ 表明：经过抚育后群落上层物种（胸径≥5 cm）和下层（1 cm≤胸径［结论］ 通过中幼林综合抚育措施，热带低地雨林次生林中短寿命先锋种数量显著减少，降低了抚育后先锋种对保留目的种的竞争强度，从而为加快热带次生林的生态功能恢复和实施森林经营管理奠定了重要基础。

以海南岛霸王岭林区内不同恢复阶段低地雨林幼苗(DBH<1 cm)层为研究对象,比较了不同恢复群落中幼苗的物种组成和功能群变化,分析了幼苗层的自然恢复动态。结果表明:不同恢复阶段幼苗层的物种组成存在显著差异;不同恢复阶段幼苗层的物种个体多度都随高度级的增加而减少,其中,第I高度级幼苗的物种数和个体多度在各个恢复时期均显著高于其它3个高度级,这说明幼苗层的存活曲线接近凹型;恢复60年的次生林群落中幼苗的个体多度最高,符合中度干扰假说;随着恢复时间的增加,不同功能群重要值表现出明显的变化规律,先锋种的重要值随恢复时间的增加逐渐减少,而耐荫种的重要值则随恢复时间的增加而逐渐增大,说明在恢复过程中耐荫种逐渐取代先锋种,从而实现了群落的更新和演替。

研究了四合木种群的径级结构、冠幅结构、高度结构和年龄结构,运用静态生命表描述了四合木种群年龄结构动态变化规律。研究表明:四合木种群株数随径级、高度级的变化呈“山峰型”,植株数随冠幅级变化成倒“J”型。现实的四合木种群年龄结构呈“凸”型。四合木种群的死亡率qx、致死力kX随龄级增大而增高,存活率lx随龄级增大而降低。其存活曲线接近于Deevey型。利用Leslie矩阵定量模拟种群动态,发现在受外界干扰很小条件下,该种群具有波动特点,各龄级的个体数变化趋势不同,种群由衰退型向增长型过渡。

The mountain region of Southwest China is not only one of the two key regions that China’s natural forests distributed, but also has lots of degraded natural forests. Its natural forests are essential to keep regional ecosystems safe and biodiversity conservation. The forests geographical zoning plays an important role in regional forests management. Based on plants geographical division and some special topic zonings published, according to zonal climax forest types, land features and drivers of degradation, this paper used the DIVA-GIS and ArcMap, divided the degraded natural forests in mountain areas of Southwest China into five zones, namely tropical rain and monsoon forests of low-mountain in South Yunnan, evergreen broad-leaf and Pinus massoniana forests over limestone in Guizhou-Yunnan, evergreen broad-leaf and Pinus yunnanensis forests of plateau in Central Yunnan, evergreen broad-leaf and Cryptomeria-Metasequoia-Cunninghamia forests of low-mountain around Sichuan Basin, dark coniferous forests over valley and mountains in Sichuan-Yunnan. Introduced the degradation state and main reasons of natural forests of each zone. Zoning of the degraded natural forests at regional level will contribute to the ecological restoration of the degraded natural forests in mountains of Southwest China.

为研究海南岛热带山地雨林不同演替阶段植物的光合特性,比较了不同光梯度下3个典型树种幼苗在晴天和阴天时的光合生理日变化过程。先锋种黄桐有最强的叶温控制能力,日变化中叶温低于中期种显脉杜英和顶极种乐东拟单性木兰。中期种显脉杜英有最高的光合生理可塑性,晴天时,显脉杜英净光合速率与黄桐差异不显著,叶温低于乐东拟单性木兰;阴天时,净光合速率和叶温与乐东拟单性木兰差异不显著。与显脉杜英相比,黄桐和乐东拟单性木兰的水分利用能力高,气孔导度、蒸腾速率低,水分利用效率高;黄桐的光合能力高,净光合速率比乐东拟单性木兰高。植物在光合能力、叶温控制能力、光合生理可塑性和水分利用能力上的差异对植物群落的演替有重要影响。

通过对海南岛霸王岭热带山地雨林林隙更新生态位的研究表明:同一树种在不同大小和年龄级林隙内的优势度不同,不同树种在同一大小和年龄级林隙内的优势度不同。根据树种在不同大小级林隙内的生态位宽度的变化,可分为生态位幅度宽、中等、较小和狭小 4类;根据树种在不同年龄级林隙内的生态位宽度的变化,可分为对林隙时间生态资源利用充分、利用较充分、利用不充分和利用很少的 4类树种。不同的树种或树种组对不同大小和年龄阶段林隙生态资源利用的不一致性,表明热带山地雨林中不同树种的林隙大小级生态位和林隙时间段生态位是相对分离的。分析表明,海南岛热带山地雨林中有很大一部分树种是属于低密度、狭生态位的树种。从物种多样性的角度来看,大量低密度、狭生态位树种的存在表明热带山地雨林是一种较为脆弱的生态系统类型。