喜马拉雅东部雅鲁藏布江大峡湾地区热带森林植被的次生演替规律初探

对雅鲁藏布江大峡弯河谷地区热带森林植被情况进行了调查分析。论述了造成该地区热带植被概况及其被破坏的自然因素和人为因素。并对该地区植被在次生演替的各个时期植被种类成分的变化，群落结构，建群种生长速度等进行比较研究，结果如下：Ａ．自然因素导致的次生演替主要经历了下列６个价段：（１）尼泊尔桤木（Ａｌｎｕｓｎｅｐｏｌｅｎｓｉｓ）阶段；（２）尼泊尔桤术单优群落阶段；（３）原生植被主要树种侵入阶段；（４）尼泊尔桤木林衰退阶段；（５）原生植被恢复阶段；（６）原生植被建立阶段。Ｂ．人为因素导致的次生演替主要经历有下列５个阶段：（１）高大禾草或热带高草阶段；（２）野芭蕉侵入生长阶段；（３）喜阳树种侵入或恢复生长阶段；（４）杂木林阶段；（５）原生植被恢复及建立阶段。最后讨论了植被次生演替规律对自然植物区系的影响和对治理山地，保护该地区生物多样性，合理利用资源及发展生产的重要性及意义。

A PRELIMINARY PROBE INTO THE SECONDARY SUCCESSION SERIES OF TROPICAL FORESTS IN THE BIG BEND GORGE OF YALU TSANGPO RIVER IN S. E. TIBET, E. HIMALAYAS

The paper presented the characters of tropical forests and their secondary succession series in the Big Bend Gorge of Yalu Tsangpo River, S. E. Tibet, E. Himalayas. In the region the tropical forests occur in the bottom of the gorge at an altitude betWeen 600- 1200 m, which belongto the low mountain semi-evergreen tropical rain forests, and include mainly three types as follows:Altingia excelsa Term mafia myriocarpa forest; Altingia excelsa Lagerstroemia mimuticarpa forestand Altingia excelsa forest. The natural and artificial factors causing the destruction of the originalvegetation were discussed. The factors led to two different secondary succession series of thesemi-evergreen tropical rain forest. The results are as follows :A. The secondary succession series caused by natural factors went through about 6 stages asfollowst Stage (1) Alnus nepalensis intruding into this area; Stage (2) Alnus nepolensis formingrelatively stationary communities, Stage (3) Dominant trees of the original vegetation invading theAlnus nepolensis community, Stage (4) The dominant trees of the original vegetation developingand Alnus nepalensis declining, Stage (5) The prevailing trees of the original vegetation graduallybecoming dominant in the community; Stage (6) The original vegetation eventually coming intobeing.B. The secondary succession series caused by artificial factors went through about 5 stages asfollows; Stage (1) Tropical high grasses intruding into and forming the community; Stage (2) Musabalbisiana invading the community; Stage (3) Heliophytes shrubs and trees intruding into and resuming growing; Stage (4) Mixed trees forming the community, Stage (5) The origmal vegetationeventually coming into being.In the end, according to the results, the paper discussed its influence on the flora of the regionand significance for bringing the mountainous region under control, protecting and making rational use of the biodiversity in the region.