Patterns of ecosystem structure across landscapes and over time provide sensitive indicators of the impact of human activities and natural disturbance. Until recently, broad-scale characterization of ecosystem structure was largely limited to two dimensions. In the past 10 years a vertical dimension has been added to landscape- and global-scale assessments using airborne and satellite-based laser techniques (lidar). Lidar instruments directly sense vertical structure by recording the “echo” from laser pulses reflecting off vegetation and ground surfaces. As lidar is applied to a range of problems in ecology and management, existing approaches to understanding the structural, functional and spatial aspects of ecosystem are beginning to be recast within the context of the three-dimensional physical ecosystem structure.