论文部分内容阅读
为精准量化水杉林带三维结构,有效提高防风效应数值模拟的精度,对水杉标准木树干、枝条和叶片的表面积和体积进行测量,建立了水杉林带的三维结构参数模型。结果表明:所选水杉林带的表面积密度的变化范围为0.0012~3.4857 m~2·m~(-3),体积密度的变化范围为0.000002~0.012397 m~3·m~(-3);水杉林带的树冠形状、树木生长状况等与林带结构密切相关;林带结构具有一定的空间异质性,枝条和叶片的表面积和体积主要集中在冠层中部,而树干则集中在下部;林带内各组分表面积和体积组成有很大区别,树干的体积较大(占总体积的75.28%),而表面积较小(占总面积的5.57%);叶片的表面积较大(占总表面积的78.39%),而体积很小(占总体积的3.87%);表面积/体积比为叶片(20.23)>枝条(0.77)>树干(0.07);与以往研究相比,模型可以全面反映林带的结构特征,更接近林带的真实结构。同时,林带表面积和体积对气流的影响作用有一定差异,利用林带的表面积密度和体积密度共同作为林带的结构参数,可以反映水杉林带各组分对气流影响的差异,更好地表现林带的空气动力学特征。
In order to accurately quantify the three-dimensional structure of Metasequoia glyptostroboides and improve the accuracy of the numerical simulation of windbreak effect, the surface area and volume of the provenances, branches and leaves of Metasequoia glyptostroboides were measured, and the three-dimensional structural parameter model of Metasequoia glyptostroboides was established. The results showed that the range of surface area density of selected Metasequoia glyptostroboides forests ranged from 0.0012 to 3.4857 m 2 · m -3 and the range of bulk density varied from 0.000002 to 0.012397 m 3 · m -3. The crown shape and tree growth status of the forest belt are closely related to the structure of the forest belt. The structure of the forest belt has certain spatial heterogeneity. The surface area and volume of the branches and leaves are mainly concentrated in the middle of the canopy, while the trunk is concentrated in the lower part. The surface area of the leaves and the volume composition are quite different. The trunk is larger (75.28% of the total volume) and the surface area is smaller (5.57% of the total area). The surface area of the leaves is larger (78.39% of the total surface area) ), While the volume was very small (3.87% of the total volume). The surface area to volume ratio of leaves (20.23)> branches (0.77)> trunks (0.07) Closer to the real structure of the forest belt. At the same time, the effect of surface area and volume of forest zone on airflow is different. Using the surface area density and bulk density of forest zone together as the structural parameters of forest zone can reflect the differences of the influence of each component of the forest, Aerodynamic characteristics.