长白落叶松人工林树冠形状的模拟

以长白山地区 2 6a生长白落叶松人工林为研究对象 ,采用枝解析的方法 ,测定了 2 5株林木 (直径 10 5～2 4 9cm)的树冠变量 ,并建立了预测树冠外侧形状的冠形模型。基于枝条着枝深度 (DINC)和林木变量所建立的树冠形状模型包括 :基径、枝长、着枝角度和弦长等预估模型。对于大小相同树木的主要枝条来讲 ,这些树冠变量是随着DINC的增加而增大 ;而林木的胸径 (DBH)和树高 (HT)变量很好地反映了不同大小树木的冠形变化。冠形预测模型预测效果良好 ,充分体现了树冠结构的变化趋势 :树冠形状在树冠的中上部呈抛物线体 ,而在树冠的下部则为近圆柱体。文中所建模型 ,可以合理地描述长白落叶松人工林的树冠形状及其变化规律。

Modeling Crown Profile of Larix olgensis Trees

Models for estimating crown profile of primary branches within live crown were developed in a 26_year_old Larix olgensis plantation in Changbai Mountain. Data of crown attributes were collected from 25 sample trees ranging in diameter at breast height ( DBH ) from 10 5 cm to 24 9 cm using the method of branch analysis. Crown profile models, including branch diameter, branch length, angle of origin, and branch chord length, were developed from branch attributes and tree variables. These crown attributes of primary branches for a specified tree increase with the depth into crown ( DINC ) increasing. DBH and total height ( HT ) were adequate variables of tree for summarizing the effects of external conditions on crown profile. The predicting models of crown profile were logical and perform well to represent the trends in crown structure. All crown shapes are parabolic in the upper and middle part of crown, and follow approximately cylinder at lower part of crown. Overall, the models were suitable in describing the trends and inherent variability of crown profile for Larix olgensis plantation.