森林冠层叶面积指数垂直分布地面间接测量及验证

森林冠层LAI垂直分布控制着森林冠层微环境及光合作用等生理生态过程，它在林学、生态学、植物学等领域均有着广泛的应用。本项目以商业化全波形地面激光雷达(Riegl VZ400）为基础，研制多光谱全波形地面激光雷达，开发可顾及树木冠层结构特征及LAI、PAI垂直分布的单树及虚拟森林环境构建方法，同时以此为基础形成具有不同林分特征、树木分布模式及地形条件的典型虚拟森林环境库，将其作为统一的森林冠层LAI垂直分布间接测量方法模拟验证平台。在虚拟森林环境下联合光线跟踪算法、投影算法、并行计算等手段实现LAI-2000、DHP、MCI、斜点样方法、MacArthur-Horn方法及多光谱全波形地面激光雷达六种间接测量方法及相关算法模拟，并以虚拟森林环境真实参考值开展验证分析，研究消除非光合作用组分影响、聚集效应、地形效应及观测方案误差来源的方法，最后提出高精度的森林冠层LAI垂直分布间接测量方案。

Foliage profile of forest canopies controls the physiological and ecological process of forest canopies, such as microenvironment, and photosynthesis etc, it was widely used in forestry, ecology, and botany etc. A multi-spectral and full waveform terrestrial laser scanner would be developed based on a commercial full waveform terrestrial laser scanner(Riegl VZ400). And next a new method for the construction of isolated tree model and virtual forest environment was developed, which can conform to the main structural characteristic parameters and the vertical PAI and LAI distribution of trees. The typical virtual forest environment library with different forest stand characteristics, the distribution model of trees and terrain effects would be build based on the construction method of trees, and used as a union platform for validating the in situ indirect methods for obtaining the foliage profile of forest canopies. LAI-2000, DHP, MCI, inclined point quadrat method, MacArthur-Horn method, multi-spectral and full waveform terrestrial laser scanner method and the corresponding algorithms would be simulated under the typical virtual forest environment library, these indirect methods were validated next based on the true reference values of virtual forest environment. And the methods for removing the four sources of errors which were widely existed for the indirect methods of obtaining the foliage profile of forest canopies will be concluded, a new scheme for the measurement of foliage profile of forest canopies needed to be proposed at last.