帽儿山主要林分类型空间结构状态综合评价

Comprehensive evaluation of spatial structure state for the main forest types in Maoershan mountain

【目的】以帽儿山实验林场主要林分类型为研究对象,通过对主要林分类型的空间结构综合评价确定影响林分结构状态的主要因素,为实现森林的合理经营和森林质量的“精准”提升提供理论基础。【方法】以东北林业大学帽儿山实验林场5种主要林分类型(白桦纯林、蒙古栎纯林、硬阔混交林、软硬阔混交林、软阔混交林)实测样地数据为基础,选取能够代表林分结构和林分活力的指标,包括林层比、角尺度、直径分布、树种多样性、林分蓄积量、林分空间优势度、林分潜在疏密度、目的树种优势度、林木稳定性和健康林木比例共10项,基于单位圆综合评价体系,对不同林分类型的林分结构状态进行综合评价,并比较不同林分类型各指标间的差异性。【结果】从结构状态指标值可以看出,不同林分类型的林层比(0.43~0.59)和林分空间优势度(0.62~0.72)差异不显著。林分的水平空间分布格局为随机分布(0.50)或轻微团状分布(0.52~0.55)。白桦纯林和软阔混交林的直径分布基本合理(1.23),其他林分类型的直径分布状态均不合理(1.12~1.14)。不同林分类型的物种多样性水平(0.39~0.79)、林分蓄积量(110.2~209.5)和目的树种优势度(0.06~0.77)均存在显著性差异;从单位圆综合评价体系可以看出,各林分类型的林分结构状态评价等级排序为硬阔混交林(0.42)>软硬阔混交林(0.41)>软阔混交林(0.37)>蒙古栎纯林(0.36)>白桦纯林(0.30)。综合来看,目的树种优势度水平偏低、直径分布不合理是导致林分结构状态较差的主要原因。【结论】基于单位圆综合指标体系的林分空间结构状态综合评价,能够直观、快速地确定林分的经营方向,加快现有林分向顶级植物群落发展的演替进程。

【Objective】The study aims to find the main factors affecting the state of stand structure through the comprehensive evaluation of the spatial structure for the main stand types of Maoershan experimental forest farm,in order to provide a theoretical basis of realizing the reasonable management and the“precise”improvement of the forest quality.【Method】Based on the measured data for five forest types(namely Betula platyphylla forest,Quercus mongolica forest,hard broadleaved mixed forest,soft-hard broadleaved mixed forest,soft broadleaved mixed forest)in Maoershan mountain,10 indicators representing stand structure and vitality were selected,including stand level rate,uniform angle,diameter distribution,tree species diversity,stand volume,stand spatial dominance,stand potential density,target tree species dominance,tree stability and proportion of healthy trees.The comprehensive structure state of different stand types was evaluated based on unit circle comprehensive evaluation system and the differences among the indicators of different stand types were compared.【Result】From the perspective of structural indicators,there was no significant difference in the stand level rate(0.43-0.59)and stand spatial dominance(0.62-0.72).The horizontal spatial distribution patterns of the stands were randomly distributed(0.50)or slightly clustered(0.52-0.55).The diameter distribution of Betula platyphylla forest and soft broadleaved mixed forest was basically reasonable(1.23),while the diameter distribution of other forest types is unreasonable(1.12-1.14).There were significant differences in tree species diversity(0.39-0.79),stand volume(110.2-209.5),dominance of target tree species(0.06-0.77);According to unit circle comprehensive evaluation system,the ranking of the stand structure state is hard broadleaved mixed forest(0.42)>soft-hard broadleaved mixed forest(0.41)>soft broadleaved mixed forest(0.37)>Quercus mongolica forest(0.36)>Betula platyphylla forest(0.30).On the whole,the low level of target tree species dominance and the unreasonable diameter distribution are the main reasons for the poor forest stand structure.【Conclusion】The comprehensive evaluation of forest stand spatial structure based on the unit circle comprehensive index system can intuitively and quickly determine the forest stand management direction,accelerating the succession process of existing forest stands to top plant communities.