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杉木林密度间伐试验历经 1 8年的定位试验研究 ,其结果表明 :(1 )同一立地指数级 ,不同初植密度的林分 ,当某一密度的林分经间伐后同另外一个密度基本相同未间伐的林分比较 ,两者优势木高、平均木高无明显差异 ;两者胸径差异明显 ,即间伐的林分小于未间伐的林分 ;两者立木蓄积 ,间伐的低于未间伐的 ;间伐林分总蓄积量 (立木蓄积 +间伐蓄积 )高于未间伐的蓄积。初植密度不同的林分 ,间伐后与未间伐林分的总蓄积量百分比 ,其比值 ,初植密度大的大于初植密度小的 ;间伐林分的枝下高一般高于未间伐林分的枝下高 ,1 6年前影响明显 ;间伐林分的冠幅一般小于未间伐林分的冠幅 ,1 1～ 1 6年时差异明显。 (2 )立地指数级不同 ,初植密度基本相同的林分 ,间伐与未间伐林分的总蓄积量百分比 ,高指数级的比值大于低指数级的比值
The results showed that: (1) In the same site with different planting density and different planting density, when the density of a certain density stands is the same as that of the other density after thinning There was no significant difference in the average height of wood between the two stands. The difference of DBH between the two stands was obvious, that is, the thinning stand was less than the un-cut stand; ; The total volume of thinning stands (standing tree accumulation + thinning accumulation) was higher than that of un-cut accumulation. The ratio of initial planting density to initial planting density was higher than that of initial planting density. The branch height of inter-thinning stands was generally higher than that of non-cut stands 16 years ago, the effect was obvious. The crown width of the thinning stands was generally smaller than that of the un-cut stand, with a significant difference between 11 and 16 years. (2) The percentage of the total volume of the stands with the same initial planting density, different stocking and unfrequented stands, the ratio of the high-index level to the low-index ratio