5个林木竞争指数模型的比较

【目的】比较计算1个Hegyi竞争指数和4个Bella竞争指数的5个林木竞争指数计算模型在评价林木竞争关系中的适应性。【方法】在吉林省汪清林业局金沟岭林场某一近原始状态的针阔混交林内设置40 m×50 m的样地，以样地内对象木5年间的胸高断面积生长量为因变量，以通过5个竞争指数模型（分别命名为H_1、B_1、B_2、B_3和B_4）计算得到的的竞争指数为自变量，构建胸高断面积生长量模型，采用模型的决定系数来评价各竞争指数模型的适应性。【结果】样地中红皮云杉、冷杉、紫椴和红松4个树种的累计胸高断面积占所有样木胸高断面积总和的比例超过80%，因此将这4个树种作为对象木进行研究。对紫椴和红松而言，模型B_1的适应性最强；对红皮云杉和冷杉而言，各个竞争指数模型的表现不一致。【结论】5个竞争指数模型在不同树种间的适应性表现不一致，说明采用单一竞争指数模型来反映混交林的竞争关系难以获得理想结果，对竞争指数模型还需要进行深入和广泛的研究。

Comparison of 5 tree competition index models

【Objective】 The study was done in order to compare the adaption of the five tree competition models,including one Hegyi’s competition index（CI） and four Bella’s CIs.【Method】 One plot representing near-natural conifer and broadleaved mixed forest,sized 40 m×50 m,was established and surveyed in Jingouling forest farm,Wangqing forest bureau,Jilin province.A regression model was formed with the basal area increment in five years as the dependant variable and the CIs as the independent variables.The dependent coefficient of the model was taken as the criterion to assess the models.【Result】 The basal area of four tree species Abies nephrolepi,Picea koraiensis,Pinus koraiensis and Tilia amurensis amounted to more than 80% of the total basal area in the plot.So they were selected as the target species for the research.As for Tilia amurensis and Pinus koraiensis,the model B₁ was the most suitable,but for Picea koraiensis and Abies nephrolepi these models did not demonstrate similar trend.【Conclusion】 The competition models demonstrated different adaption among these tree species,showing that the competition model with one variable could not fully demonstrate the competition relationship for mixed forest and more work on the competition models is necessary.