密度调控对金佛山方竹低产人工林结构的影响

The Influence of Density Adjustment on the Structure of the Planted Low-yield Forests of Chimonobambusa utilis

在其它经营措施相同条件下,分析了10年生金佛山方竹低产人工林中l 500 ～2 500株/0.07hm^2（A）和2 500 ～3 500株/0.07 hm^2 （B）两个密度级的林分特征指标变化.4年密度调整期内竹林平均地径、高度和地径整齐度呈稳定增长趋势.A密度等级的平均地径在2010和201 1年同2012和2013年间差异显著,B密度等级的平均地径在2010年同2012和2013年间差异显著.A和B两个密度等级的平均高度在2010和2011年同2012和2013年间差异显著.竹林立竹个体差异变小,不同密度等级竹林的径级株数分布峰值随改造时间延长向大径级方向推移,X^2适应性检验表明不同密度等级竹林年度间的径级株数分布差异达极显著水平.立竹分布均匀度在年度间呈规律波动、整体呈下降趋势.在A和B密度等级、以及2年未间伐竹林中,地径随年龄降低而增大,1年生竹较其它3年生竹的径级增长率分别为23.68％、21.79％、-6.04％,1年生竹同4年生竹径级、1年生竹和4年生竹径级同2～3年生竹径级的差异达显著水平,未间伐竹林中枯竹同1～3年生竹径级的差异达显著水平.不同措施处理中,1年生竹径级差异显著,径级差异的显著性随立竹年龄增大而减弱,间伐和未间伐竹林的相同年龄径级间差异显著.

The stand structure characteristics of a 10-year-old planted forest of Chimonobambusa utilis under two density treatments （treatment A,1 500 ～ 2 500 shoots per 0.07 hm^-2 ; treatment B,2 500 ～ 3 500 shoots per 0.07 hm^-2） were studied.The results showed that the average shoot diameter at ground,average shoot height and uniformity of the shoot diameter at ground steadily increased in the 4a density adjustment period.The average shoot diameters at ground in 2010 and 2011 were significantly different from that in 2012 and 2013 under A density treatment.The average shoot diameter at ground in 2010 was significantly different from that in 2012 and 2013 under B density treatment.The average shoot heights in 2010 and 2011 were significantly different from that in 2012 and 2013 under both A and B density treatments.With the extension of density adjustment,the differences among bamboo individuals reduced,and the shoot diameter at ground under various densities became larger.X^2-test showed that the shoot diameters at ground under different density treatments were significant different between years.Under A and B density treatments and the control （nothinning）,the younger the bamboo shoots,the bigger the average diameter at ground,the differences between 1a and the other 3a were 23.68%,21.79% and-6.04% respectively.The differences of the diameter at ground between 1a and 4a,between 1a,4a and 2a,3a were significant.Under no-thinning control,the diameter at ground of between the dead and 1 ～ 3a surviving bamboo shoots were significant.The diameter at ground of 1 a shoots were significant different between different treatments,and the differences decreased with the increase of bamboo age.The diameters at ground of same age class were significantly different between the thinning and no-thinning treatments.