红松人工林叶面积分布规律及回归模型研究

Study on the Distribution Law and Regression Model of Leaf Area in Korean Pine Plantation

叶面积的大小可以对树木的生长和生命活动产生深远的影响,进而关系到树木生物量的变化和森林生态的发展趋势,叶面积的研究可以对树木的相关分析起到较为关键的作用。基于黑龙江省48株红松人工林解析木数据和排水法测定的叶面积数据,建立基础线性回归模型,后引入随机效应参数构建混合效应回归模型以提高拟合效果和预估精度。在加入树木层次的随机效应时,最终得到的最优混合效应模型含有3个随机效应参数,分别为枝条基径的对数(lnBD)、枝条长度的对数(lnSL)、树高的对数(lnHT)。该模型的R_(a)^(2)=0.86,平均绝对偏差M_(AE)=0.3428,均方根误差R_(MSE)=0.4841,统计指标较仅包含固定效应的基础线性模型均有较好的提高。综合分析得出该模型可以较好地对红松枝条叶面积大小进行描述。基于该模型计算红松树冠叶面积并得到混合效应预估模型,混合模型的R a 2=0.83,R_(MSE)=0.4429。通过检验结果可知该模型可以较好地对红松树冠叶面积进行预估计算,为日后该地区人工红松的经营提供良好的指导方向。

The size of the leaf area can have a profound impact on the growth and life activities of the tree,and then it is related to the change of the biomass of the tree and the development trend of the forest ecology.The research on leaf area can play a key role in the correlation analysis of trees.Based on the analytical wood data of 48 Korean pine plantations in Heilongjiang Province and the leaf area data measured by the drainage method,a basic linear regression model was established,and then random effect parameters were introduced to construct a mixed effect regression model to improve the fitting effect and prediction accuracy.When random effects at the tree level were added,the optimal mixed effect model obtained contained three random effect parameters,namely logarithm of branch base diameter(lnBD),logarithm of branch length(lnSL),and tree height logarithm(lnHT).The R^(2) a was 0.86,the MAE was 0.3428,and the RMSE was 0.4841.The statistical indicators were better than the basic linear model that only included fixed effects.The comprehensive analysis showed that the model can better describe the leaf area of Korean pine branches.Then,based on the model,the crown leaf area of the Korean pine tree was calculated and a mixed effect prediction model was obtained.The mixed model R^(2) a was 0.83 and the RMSE was 0.4429.Through the test results,it can be seen that the model can predict the crown and leaf area of Korean pine trees better,and provide a better guiding direction for the future management of artificial Korean pine in this area.