抚育间伐对栓皮栎人工林直径和树高分布的影响

【目的】以河南登封林场栓皮栎人工林为研究对象,研究抚育间伐对林分不同生长阶段林木株数、林木直径分布和树高分布的影响,为制定科学合理的抚育经营措施奠定理论和技术基础。【方法】在株数强度为31.55%的间伐林分和条件基本一致的未间伐林分内,分别设置1个1 hm2样地,间伐作业2 a后获取每木检尺数据,分别利用Normal分布、Gamma分布、Lognormal分布、Weibull分布、Logistic分布函数对间伐样地和对照样地栓皮栎人工林林木个体直径分布、树高分布进行拟合,并应用Kolmogorov-Smirnov(KS)拟合优度检验,选择拟合效果最好的分布模型。【结果】1)间伐和对照样地幼树、小树和大树林木株数比例分别是9:642:582和229:978:585。相比对照样地,间伐样地林木小树和大树生长阶段株数比重较高。2)间伐样地林木直径分布范围主要集中在8~18 cm,高于对照样地的4~16 cm。KS拟合优度检验结果表明,间伐样地林木直径分布采用Weibull分布拟合效果最好,Normal和Logistic分布次之;对照样地林木直径分布采用Weibull分布拟合效果最好,Normal和Gamma分布次之。3)间伐样地和对照样地林木树高级分别为8~16 m和4~14 m,但KS拟合优度检验结果表明,5种分布函数对间伐样地和对照样地树高分布拟合优度排序一致,说明抚育间伐对林分树高分布的影响不明显。【结论】抚育间伐调整了栓皮栎人工林林分的直径结构,林分直径分布向较大径阶方向偏移,使林分直径分布结构更趋于对称分布,但对树高分布影响不明显。

Effect of thinning on distribution of tree diameter and height in Quercus variabilis plantation

【Objective】Taking the Quercus variabilis plantation in Dengfeng forest farm of Henan province as the research object,the effects of thinning on the diameter distribution and tree height distribution of the forest were studied,which laid a theoretical foundation for guiding the tending of broad-leaved tree plantation.【Methods】One 1 hm2 plots were set up,respectively,in the thinning forest with a plant strength of 31.55%and the not tending forest with the same conditions were basically the same.After 2 years of thinning operation,the data of each wooden ruler was obtained.The Normal distribution,Gamma distribution,Lognormal distribution,Weibull distribution and Logistic distribution function were used to analyze the individual diameter distribution and tree height distribution of the Quercus variabilis plantation forest in the thinning plot and the control plot.The Kolmogorov-Smirnov(KS)goodness-of-fit test was used to select the best distribution model.【Result】1)The proportions of saplings,small trees and large forest trees in thinning plots and control plots were 9:642:582 and 229:978:585,respectively.Compared with the control plot,the proportion of the number of plants in the growth stages of small trees and large trees in the thinning plots is higher;2)The diameter distribution of forest trees in the thinning plot is mainly concentrated at(8-18 cm)higher than the control plot(4-16 cm).The results of KS goodness-of-fit test showed that the Weibull distribution was the best for the diameter distribution of the cultivating plots,followed by the Normal and Logistic distributions.The Weibull distribution was the best for the diameter distribution of the control stands,and the Normal and Gamma distributions were the second.3)The high-level trees and the control plots were between 8-16 m and 4-14 m,respectively,but the results of KS goodness test showed that the five distribution functions were distributed to the tree height of the tending plot and the control plot.The order of goodness was consistent,indicating that the effect of tending on the high distribution of broad-leaved forest trees was not significant.【Conclusion】The thinning structure of the forest of Quercus variabilis artificial was adjusted,and the diameter distribution of the stand was shifted to the direction of the large diameter,which made the distribution of the diameter of the stand more symmetric,but the effect on the distribution of tree height was not significant.