论文部分内容阅读
在 8年、 1 2年、 1 6年生湿地松人工林中布设不同间伐强度试验林 ,对不同间伐处理的林分测树因子和间伐作业经济效益进行了分析 ,结果表明 ,间伐对林木生长具有一定的促进作用 ,对幼龄林的促进作用明显大于中大龄林分 ,随着间伐强度增大 ,较大径阶立木株数比例随之增加 ,但期末总收获量减少 ;湿地松人工林首次间伐宜在 1 2年生之前进行 ,保留 90 0～ 1 1 0 0株 / hm2 ,在造纸材销路较好的地区 ,且初植密度较高的林分 ,可在 8年生时进行首次间伐 ,保留 1 4 0 0株 / hm2 ;第二次间伐的间隔期为 6年 ;以培育大中径材为目标的大龄林分应以弱度调整为主 ,保留 60 0株 / hm2 ;另外 ,间伐有利于提高保留木材性的均质性
In the 8 years, 12 years and 16 years old wetland pine plantations were planted different thinning strength of the experimental forest, different thinning of the measured tree factors and thinning operation of the economic benefits were analyzed, the results show that the thinning on the growth of trees with The promotion effect on young forest was obviously greater than that of middle-aged forest. With the increase of thinning intensity, the proportion of larger-diameter tree was increased, but the total harvest decreased at the end of the period. The first thinning of Pinus elliottii plantation Should be carried out before 12 years old, with 90 0-1,110 plants / hm2 reserved. In the areas with good paper-making materials sales and the higher planting density, the first thinning can be carried out at the time of 8-year birth, and the reserve 1 4 0 0 plants / hm 2; the interval of the second thinning was 6 years; the large-scale stands for cultivating large and medium diameter timber should be mainly weakness adjustment with 60 0 plants / hm 2 retained; Increase the homogeneity of wood retention