基于CAPV的大兴安岭天然次生混交林林分结构特征

Stand structure characteristics of secondary mixed forests in Great Xing’an mountains based on CAPV

【目的】探明大兴安岭加格达奇地区天然混交林林分结构特征,为该地区森林结构化经营提供理论依据。【方法】以大兴安岭加格达奇林业局天然次生混交林为研究对象,以6种概率分布模型研究林分直径分布,采用角尺度、大小比数、混交度、密集度4种林分空间结构参数以及两种空间结构综合指数对其空间结构进行分析与评价。【结果】林分直径分布特征以对数正态分布的拟合效果最好。引入林分空间结构指数FSI,根据FSI与各参数平均值相关性确定权重为混交度>密集度≥角尺度>大小比数。参考综合距离指标CDEV,建立了一种新的林分空间结构研究方法CAPV,综合分析不同标准地的4种林分空间结构参数,蒙古栎-黑桦混交林即树种配置为4蒙古栎3黑桦1白桦1杨树、林分密度为1400株/hm2的林分空间结构最优,其CAPV值为0.678。【结论】大兴安岭加格达奇地区天然混交林林分结构存在着一定的不合理性,树种结构单一,径阶分布多集中在小径阶,且同种树种容易聚集,可以结合二元及三元分布三维图,参考综合指数,制定相应补植改造、抚育间伐措施,优化林分结构。

【Objective】To ascertain the structure of secondary mixed forests in the Jiagedaqi area of the Great Xing’an mountains,and to provide theoretical basis for managing the forest structure in this area.【Method】Taking the secondary mixed forests of the Jiagedaqi forestry bureau in the Great Xing’an mountains as the research object,the diameter distribution of the forest stands was studied by using six probability distribution models,four structure parameters(uniform angle index,neighborhood comparison,mingling degree,and crowding degree)and two kinds of spatial structure comprehensive indexes were used to analyze the characteristics of stand spatial structure.【Result】The characteristics of stand diameter distribution showed that the lognormal distribution fitted best.The forest spatial structure index(FSI)was introduced,and the weights were determined according to the correlation between the FSI and the average value of each parameter as:mingling degree>crowding degree≥uniform angle index>neighborhood comparison.A new stand spatial structure research method CAPV was established with reference to the comprehensive distance indicator CDEV,and we comprehensively analyzed the four spatial structure parameters of different stand types.The Mongolian oak-black birch mixed forestwhich the tree species configuration was 4 Mongolian oaks and 3 blacks and the stand density was 1400 plants per hectare,the spatial structure was the best.Its CAPV value was 0.678.【Conclusion】There was some irrationality in the stand structure of natural mixed forests in the Jiagedaqi area of the Great Xing’an mountains.The tree structure was single,the diameter distribution was mostly concentrated in the small diameter,and the same tree species were easy to gather.Combined with the three-dimensional distribution map of bivariate and trivariate distribution,with reference to the comprehensive index,formulate corresponding replanting and transformation,tending and thinning measures,and optimize the stand structure.