This book demonstrates modern methods for using airborne and ground-based active and passive 3D remote sensing to estimate plant properties such as canopy height, canopy structure, carbon stock, and species. Understanding and diagnosing plant responses to environmental change can greatly benefit from three-dimensional (3D) measurement and analysis of plant properties because plant responses are closely related to their 3D structures. In particular, Light Detection and Ranging (LiDAR) has recently emerged as a powerful tool for the direct 3D measurement of plant structure. Furthermore, the book assesses plant growth and shape responses and reviews the development of selected active and passive 3D systems and their applications from the leaf level to canopy remote sensing. In addition, the authors demonstrate their recent efforts to combine 3D measurement methods with other optical methods in order to obtain vegetation index, chlorophyll fluorescence, and leaf temperature images, thereby providing essential information on how pigments, photosynthesis, transpiration, stomatal opening, and shape respond to environmental stresses. These cutting-edge methods make it possible to analyze 3D information on ecophysiological responses and levels of various substances in agricultural and ecological applications including phenotyping, and in observations of the global biosphere.