Terrestrial Laser Scanning (TLS) is increasingly being used to characterize forest structure and complexity. Detailed 3D lidar reconstructions of individual trees and forest stands provide the opportunity to digitally model woody volume, estimate biomass, and monitor forest disturbance, dynamics, and productivity over time. A range of commercial and research terrestrial lidars have been deployed at a number of international research sites. The NSF-funded Research Coordination Network (RCN - NSF DBI-1455636): Coordinating the Development of Terrestrial Lidar Scanning for Aboveground Biomass and Ecological Applications has served to foster this international collaboration and encourage best practices for TLS deployment. A dedicated RCN sponsored field campaign was carried out in 2017 to establish protocols, and compare the ability of various TLS instruments to scan, measure, and model destructively sampled plots at the Harvard Forest LTER in central Massachusetts.
Results/Conclusions
In addition to the destructively harvested plots, repeated annual terrestrial lidar scans of the 35 hectare Smithsonian/CTFS Forest Global Earth Observatory (ForestGEO) plot at Harvard Forest have also been undertaken to monitor the advance of the hemlock woolly adelgid (Adelges tsugae) infestation. This infestation is currently causing widespread canopy degradation and mortality of eastern hemlock stands (Tsuga canadensis) in the region. Reduction in the evergreen hemlock canopy is leading to increased understory illumination and rapid expansion of successional deciduous trees, resulting in changes to the surface hydrology and surface radiation budget. TLS reconstructions of forest canopies from Harvard Forest, and from other research sites round the world (such as Wytham Woods, a ForestGEO site in the UK, and La Selva Biological Station in Costa Rica), as well as some urban and arboretum tree reconstructions, will be presented to provide an overview of the current use of terrestrial lidar to capture forest structure and ecophysiology.