Lidar is a form of remote sensing in which laser pulses are reflected off objects to create three-dimensional maps. Recent technical advances have made acquiring and processing lidar data more efficient. Oregon State University and the USGS are examining the value of lidar for ecological studies ranging from individual trees to landscapes. One objective is to develop a lidar tool to identify once-widespread Oregon white oak trees under encroaching conifer canopies. The new tool will help map the regional distribution and condition of the oak and help model the effects of land-use and climate change on lowland ecosystems. Lidar will also be used to describe structure of understory vegetation in young, mature, and old-growth forests in order to improve wildlife habitat models.