A Decade Dynamics of Equatorial Rain Forest System in Sumatra

这项研究在印度尼西亚西苏门答腊省巴东市附近的Gunung(山)Gadut地区建立的永久样地上完成了大约十年的普查，并分析了那里物种极其丰富的植物群落的十年动态。6个永久性样地包括海拔梯度和演替梯度，包括海拔600m的山麓雨林中的两个主要1公顷样地，即皮南皮南样地和嘎查布伊样地。两个主要样地分别有310种和250种树种，胸径在8 cm以上，是热带雨林物种丰富度的最大记录。极端潮湿的气候被认为是造成这一记录的原因。这种丰富度与森林的层次化有关。采用一种新的剖面栅格摄影技术定量描述了叶片分层现象。与日本暖温带雨林相比，山地森林具有较少的层次化结构，同时乔木区系更多样。主要分布在林隙和次生林中的先锋树种在生境上也有不同程度的干扰，存活树的生长和小树更新的生物量增量与两个主要样地因树木死亡造成的生物量损失相平衡，年周转率约为0.02。树种的生态性状可用胸径生长率进行分类。亚冠层树种的相对生长率普遍较低，约为0.005株/年，林隙的形成影响后续树种的生长速度。对树木空间分布的分析表明，小树在枯死树附近的更新是频繁的。新生树种和冠层树种在母树和已建树苗的空间分布上呈负相关，而亚冠层树种在空间分布上不呈负相关。

This research completed about ten-year censuses in permanent plots established in Gunung (Mount) Gadut area near Padang City of West Sumatra Province, Indonesia, and analyzed ten-year dynamics of extremely species-rich plant communities there. Six permanent plots cover altitudinal and successional gradients, including two main 1-ha plots namely Pinang Pinang Plot and Gajabuih Plot in foothill rain forests at ca. 600 m above sea level.The two main plots contained 310 and 250 tree species above 8 cm dbh (trunk diameter at breast height), which is the maximum record of species richness in tropical rain forests. Extremely wet climate was hypothesized to cause this record. The richness was related to the stratification of the forest. Foliage leaf stratification was quantitatively described by a new profile grid-photograph technique. Montane forests showed less stratified structure, meanwhile more diverse tree flora than Japanese warm-temperate rain forests. Pioneer tree species occurring mainly in treefall gaps and secondary stands were also differentiated in their habitats in terms of disturbance regime.The biomass increment due to growth of survived trees and recruitment of small trees was balanced with the biomass loss due to tree death in two main plots, and its turnover rate was about 0.02 per annum. Ecological traits of tree species could be classified by dbh growth rate. Subcanopy tree species had generally low relative growth rates, ca. 0.005 per annum.Gap formation affected growth rate of successor trees. Analysis of spatial distribution of trees suggested that recruitment of small trees was frequent around dead trees. Emergent and canopy tree species showed negative correlation in spatial distribution between mother trees and established saplings, while not for subcanopy tree species.