天山西部林区云杉林更新中畜害的研究

畜群为害云杉林更新的主要方式是践踏。苗高50cm以上的云杉大苗比苗高20cm左右的普通苗受畜害程度明显要轻。林地天然更新苗木密度与畜群活动频次的关系为:y=0.062 82+0.000 086 68(3.935 3-0.860 1(x~(1/2)))~(10),式中y表示100m~2内平均更新株数,x表示草地在10d(天)中被取食遍次。在天山林区用苗高50cm以上的云杉大苗进行人工更新造林及用围栏管护更新林地,能有效地减轻畜群对更新的践踏为害。

A Study of the Harmful Effects of Animal Herds on Spruce Forest Regeneration in the Western Tianshan Mountain Forest Area

The principal way that animal herds harm the regeneration of spruce is by trampling. Seedlings with a height over 50cm are less vulnerable than the common seedlings whose height is about 20cm. This paper shows the relationship between seedlings' density and the frequency of activity of the herd: y=0.06282+0.0008668 (3.935 3—0.8601X(1/2))~10. Where y is the average number of seedlings in a 100m~2 area, x is the frequency of the grassland bitten within a 10 day period. By either using spruce seedlings whose height is over 50cm, or enclosing grassland areas used in forest regeneration, one can effectively reduce the damage to seedlings from animal herds.