基于混合效应模型的林分优势木平均高-平均胸径模型研究

Research on average height and average DBH model of dominant trees in forest stands based on Mixed Effect Model

混合效应模型逐渐被应用于林业领域,其不仅能描述数据整体的变化规律,还能反映数据之间的变化,使估计结果时更为准确。通过胸径来推算树高在一定程度上为林业调查提供了便利,以会理市123块样地为研究对象,构建林分优势木平均高-平均胸径混合效应模型,分析林分优势木平均高与平均胸径的相关关系,研究结果表明:(1)林分优势木平均高与平均胸径之间的相关关系极显著。(2)幂函数模型的拟合效果无论在单个树种之间还是在整体上均表现最好(3)混合效应模型不仅可以反映林分优势木平均高在平均胸径上的整体变化趋势,还能体现不同树种对其产生的影响,A IC、BI C的表现更优,模型拟合效果更好。

The Mixed Effect Model is gradually being applied in the forestry field,which can not only describe the overall change law of data,but also reflect the changes between data,making the estimation results more accurate.Calculating tree height by diameter at breast height provides convenience for forestry investigation to a certain extent.Taking 123 sample plots in Huili City as the research object,the mixed effect model of average height and average DBH of dominant trees in forest stands was constructed,and the correlation between average height and average diameter of dominant trees in forest stands was analyzed.The research results showed that:(1)The correlation between average height and average DBH of dominant trees in forest stands was extremely significant.(2)The fitting effect of the power function model was the best both among individual trees on the whole.(3)The Mixed Effect Model could not only reflect the overall change trend of the average height of dominant trees in forest stands on the average DBH,but also reflect the impact of different tree species.The performance of AIC and BIC was better,and the model fitting effect was better.