南京林业大学学报(自然科学版) ›› 1981, Vol. 24 ›› Issue (01): 70-80.doi: 10.3969/j.jssn.1000-2006.1981.01.003

• 研究论文 • 上一篇    下一篇

西藏亚高山暗针叶林的分布与生长

徐凤翔   

  1. 南京林产工业学院林学系
  • 出版日期:1981-03-18 发布日期:1981-02-18

THE DISTRIBUTION AND GROWTH OF THE DARK CONIFEROUS FORESTS IN XIZANG

Xu Fengxiang   

  • Online:1981-03-18 Published:1981-02-18

摘要: <正>一、西藏东南部拥有极丰富而特异的地貌类型、生态类型、生物种群和森林植被类型。藏东南林区有大面积古老,健康而完好的天然森林生态系统。其中亚高山暗针叶林是分布广、面积大、稳定性强、生物生产量高的森林群系。 二,西藏亚高山暗针叶林是寒温带暗针叶林分布最南、最高的林区之一。由于地带三向性的分异,亚高山暗针叶林有明显的水平分区和垂直分带。在各区,带中,森林群系,建群种,林型及其生长状况都有明显的差异。 三,西藏亚高山暗针叶林的水平分布可分为三亚区:(1)三江流域峡谷、山原块状暗针叶林亚区;(2)喜马拉雅山南麓高山峡谷湿润暗针叶林亚区;(3)雅鲁藏布江中下游沟谷暗针叶林亚区。 在分布区的海拔2700—4300米的垂直带内,分布有云杉林群系、冷杉林群系和圆柏林群系。各群系的分布带内,随水热状况的变化组成有规律的林型垂直分布带谱。 四、西藏亚高山暗针叶林的生长特点为;立木高大,生长持续期长,林分蓄积量高。在喜马拉雅山南麓湿润区,云杉林分的蓄积最高达每公顷3500余立方米,平均胸径111厘米,平均高67米。立木最大胸径162厘米,最大树高72米。 五、不同海拔高度与坡向的暗针叶林林分生长差异显著。在喜马拉雅山南麓湿润区,云杉的最适分布带在海拔2700—2800米,冷杉的最适分布带在海拔3600—3700米。北坡的林分生长远优于南坡。

Abstract: 1. The southeastern part of Xizang is abundant in its specific topography, ecotype, biotic population and forest vegetation. In this region, there exist a large number of ancient, healthy and natural forest ecosystems, among which the subalpine dark coniferous forests are found to be a widly distributed, extensively stretched, stable and high productive formation group.2. The subalpine dark coniferous forests in Xizang are among the cold-temperature dark coniferous forests, which are lotatcd in the southern-most part and at the highest altitude. Due to the habitat diversity of the three main slopes of this mountainous region, horizontal districts and vertical zones are distinctly presented. They are different from each other in dominant trees, forest types and growth con? ditions.3. Horizontally, the area covered by subalpine dark coniferous forests in Xizang can be divided into three districts, namely:(1) Dispersed subalpine dark coniferous forestplots in the gorges in the Three Rivers area.(2) The moist subalpine dark coniferous forests in the valleys at the southern foot of Mt. Himalaya.(3) The subalpine dark coniferous forests in the canyon along the middle and lower reaches of the Yalu-Tsangpo River.Picea, Abies and Sabina formations occur at the elevation from 2700 to 4000m, each composed of different forest types based on different thermol and water conditions.4. The characteristics in the growth of the subalpine dark coniferous forests in Xizang are their tallness, longevity and high production. In the humid area at the southern foot of Mt. Himalaya, a Picea stand holds the maximum volume of 3500 m3 per hectare, with a mean diameter of llicm. and an average height of 67m. In the same stand the maximum diameter of an individual tree is 162cm and the maximum height is 72m.5. The growth of the subalpine dark coniferous forests vary distinctly at different elevations as well as in different slop 2 directions. At the humid southern foot of Mt. Himalaya, 2700-2800 m is the optimum growth altitude for Picea and 3600-3700 m. for Abies. Forest stands on the southern slopes grow much better than those on the northern slopes.