不同疏伐方法对杉木林生长和产量的影响

<正>在９年生的杉木人工林中，设立抚育间伐方法试验标准地。试验处理为上层疏伐、下层疏伐、综合疏伐、机械疏伐和对照５种。于１９７５年、１９７８年、１９８２年、１６８６年分别测定了各标准地的大小因子。分析结果表明，各种疏伐方法对林分生长和产量的影响显著不同，杉木幼林首次疏伐时，机械疏伐效果最好。

INFLUENCE OF DIFFERENT THINNING METHODS ON GROWTH AND YIELD OF CHINESE FIR PLANTATION

The experimental plots were set up on a 9-year-old Chinese fir plantation, where different thinning methods, such as thinning from above, thinning from below, thinning from above and below, mechanical thinning and control plot were carried out in 1975. The thinning intensity is about 30 Percent of the number of trees. The height. breast diameter, hasal area of trees were measured in 1975, 1978, 1982 and 1986 respectively. The results show that different thinning methods have different effects on the growth and yield of the Chinese fir plantations. hased on the analysis of the tree increment, mechanical thinning is the best when the first thinning is carried out on a young Chinese fir plantation.