抚育间伐对不同年龄杉木人工林生长及林下植被多样性的影响

Effects of thinning on growth and understory vegetation diversity of Chinese fir plantation at different ages

【目的】研究抚育间伐对不同年龄杉木林分生长和林下植被多样性的影响,旨在明晰抚育效益,为杉木人工林提质改造提供理论依据。【方法】以8年生、13年生、18年生杉木人工林为研究对象,分别设置抚育(25%株数间伐强度)与对照(不间伐)两种处理,连续4年对林木生长和林下植被进行观测。【结果】抚育间伐促进了树高、胸径、单株材积和蓄积的增长,8年生、13年生杉木树高年生长量抚育间伐与对照之间均达到显著水平(P<0.05),18年生杉木无显著性差异。3种年龄杉木抚育间伐与对照之间胸径和单株材积年生长量均具有显著性差异(P<0.05)。8年生、13年生杉木抚育间伐与对照之间蓄积年生长量有显著性差异(P<0.05),18年生杉木无显著性差异(P>0.05)。抚育间伐改善了杉木干形,3种年龄杉木树干林分平均实验形数均为抚育大于对照,抚育间伐对8年生、13年生杉木树干实验形数的变动幅度有显著性影响(P<0.05),对18年生杉木无显著性影响(P>0.05)。抚育间伐4年后,3种年龄杉木林下植物种类比对照分别增加了7、6、4种,林下植被Shannon-wiener、Simpson和Pielou指数均呈增加趋势,抚育间伐与对照之间Shannon-Wiener和Pielou的变化值有显著性差异(P<0.05),Simpson的变化值差异不显著(P>0.05)。8年生、13年生、18年生杉木的抚育间伐效益分别为17.39%、56.06%和23.15%,3者之间差异显著。【结论】抚育间伐可以促进不同年龄杉木人工林生长,改善林木干形,提高林下植被多样性,缩短林木成材期,持续发挥其多功能效益。

【Objective】To study the effect of thinning on the growth of different age Chinese fir stands and the diversity of undergrowth vegetation,in order to clarify the benefits of tending and provide theoretical basis for improving the quality of Chinese fir plantation.【Methods】Taking 8-year-old,13-year-old and 18-year-old Chinese fir plantation as the research object,the growth and undergrowth of trees were observed for 4 years in succession by setting up tending(25%thinning intensity)and control(no thinning)treatments respectively.【Results】Thinning promoted the growth of height,DBH,volume and volume of individual tree.The annual growth of height of Chinese fir trees in 8-year-old and 13-year-old reached a significant difference(P<0.05)between thinning and control DBH and annual growth of individual tree between stands of three ages of thinning and control treaments(P<0.05).There was a significant difference in the annual growth of volume of Chinese fir trees between the 8-year-old and 13-year-old thinning and control treaments(P<0.05),but there was no significant difference in the 18-year-old Chinese fir trees(P>0.05).Thinning improved the stemshape,and the number of trunk experimental shapes of Chinese fir stands at three ages was higher than that of the control treament.Thinning had a significant effect on the change range of experimental shapes of Chinese fir stands at 8-year-old and 13-year-old(P<0.05),but no significant effect on the Chinese fir stands at 18-year-old(P>0.05).After thinning for 4 years,there were 7,6 and 4 species of undergrowth plants in the three ages of Chinese fir trees compared with the control treament,and the variation value of Shannon-Wiener,Simpson and Pielou all showed an increasing trend.There was a significant difference in the variation value of Shannon-Wiener and Pielou between thinning and control treaments(P<0.05),but there was no significant difference in the variation value of Simpson(P>0.05).The thinning benefits of 8-year,13-year and 18-year-old Chinese fir were 17.39%,56.06%and 23.15%respectively.【Conclusion】Thinning can promote the growth of different ages Chinese fir plantation,improve the stem shape of trees and the diversity of undergrowth vegetation,at the same time shorten the timber period,and continue to play its multi-functional benefits.