西藏更张沟高山松的天然更新

ON NATURAL REGENERATION ALPINE PINE IN GENGZHANG GULLY, XIZANG

西藏更张沟距林芝地区(八一新村)西35km,地理位置是东经94°05′,北纬29°44′。该沟为泥石流冲击而成,由西南向东北延伸达30km,从海拔3120m上升到3700—4000m,面积约20km^2(包括两边山坡)。气候状况参考林芝县(海拔3000m,距更张沟53km)气象资料,年平均温度8.5℃,≥10℃积温2262.8℃,1月平均气温0.2℃,7月平均气温15.5℃,年降水量654.1mm,年蒸发量1697.2mm,相对湿度63％,年日照时数2022.2,无霜期195.2天。

Investgations were carried out from 1979 to 1981 on the natural regeneration of the alpine pine in Gengzhang Gully, Xizang. The results show that the stand types are mainly pteridophyta, alpine oak, and alpine pihe, and that their distrbution areas are comparatively large. Alpine pines grown on flood land and in the middle-lower parts of the slopes are mostly Ⅱ and Ⅲ age-dasses, their increments are high with good, and natural regeneration As a resoult of poor seed sources in the forest, there only 1—10 year-old young seedlings and trees, about 2000—115000 plants per hectare, and grow badly. We suggest that some measures should be token to promote the natural regeneration, such as by strip clear cutting, heavy selective fellings, direct seeding and forest cleaning.