抚育间伐对杉木人工林生长的影响

Effect of thinning on growth of Chinese-fir plantation

对12年生杉木人工林进行2次间伐,其中第1次间伐时林龄为12年,第2次间伐时林龄为17年,并于23年生时主伐,采用不同间伐强度和不同间伐方法研究抚育间伐对杉木人工林生长的影响。结果表明:以B处理(第1次为35%、第2次间伐强度为15%)的间伐强度较为适宜,主伐时单位面积累计蓄积量(间伐+主伐)最大,其胸径增长和林分立木蓄积量最大;以下层疏伐的处理主伐时的单位面积蓄积量最大,对杉木林分生长的促进效果较好;不同抚育间伐强度对主伐时大、中径级(胸径14 cm以上)林木株数的比例有较大影响,也以B处理的强度最为适中,大、中径级林木株数所占比例最高;2种间伐方法的大、中径级林木株数的比例没有明显差异。

With the 12-year-old Chinese-fir plantation for 2 thinning, including 1st thinning at stand age of 12 years old and 2nd thinning at stand age of 17 years old, for felling at stand age of 23 years old, the effect of thinning on growth of Chinese-fir plantation was studied by using different thinning intensity and different thinning methods. The results showed that the B treatment with thinning intensity of 1st 35% 2rid 15% was more appropriate, by which the total stock volume per unit area （thinning ＋felling） was the maxi- mum and the DBH growth and stand volume were also the maximum. The method of thinning from below had better effect on growth of Chinese-fir, by which the stock volume per unit area （felling） was the maximum. The different thinning intensity had a great influence on the quantity proportion of trees with large and medium DBI-I class （ more than 14 cm）, and the B treatment was the m^st suitable for the highest quantity proportion. But there was no obvious difference in the quantity proportion of trees with large and medium DBH class between the two thinning methods.