Retrieving Forest Structure using Echidna® Ground-Based Lidar

Alan Strahler, Boston University, alan@bu.edu
Crystal Schaaf, Environmental Earth and Ocean Sciences, schaaf@bu.edu (Presenter)
Tian Yao, Boston University, tianyao@bu.edu
Feng Zhao, Boston University, zhao26@bu.edu
Xiaoyuan Yang, Boston University, xiaoyuan@bu.edu
Curtis Woodcock, Boston University, curtis@bu.edu
David Jupp, CSIRO Marine and Atmospheric Resources, david.jupp@csiro.au
Darius Culvenor, CSIRO Sustainable Ecosysems, darius.culvenor@csiro.au
Glenn Newnham, CSIRO Sustainable Ecosystems, glenn.newnham@csiro.au
Jenny Lovell, CSIRO Marine and Atmospheric Resources, jenny.lovell@csiro.au

A ground-based, scanning, near-infrared (1064 nm) lidar, the Echidna® validation instrument (EVI), built by CSIRO Australia, retrieves structural parameters of forest stands rapidly and accurately, and by merging multiple scans into a single point cloud also provides 3-D stand reconstructions. Scans and field work in the USA (New England in 2007 and the Sierra Nevada of California in 2008) show that retrievals of mean tree diameter, stem count density (stems/ha), basal area, above-ground woody biomass, and leaf area index for 1-ha plots match conventional field measurements very well. Parameters retrieved from five scans located within six 1-ha stand sites matched manually-measured parameters with values of R2 = 0.94–0.99 in New England and 0.92–0.95 in the Sierra Nevada.

Retrieved leaf area index (LAI) values were similar to those of LAI-2000 and hemispherical photography. In New England, an analysis of variance showed that EVI-retrieved values were not significantly different from other methods (power = 0.84 or higher). In the Sierra, R2 = 0.96 and 0.81 for hemispherical photos and LAI-2000, respectively. Foliage profiles, which measure leaf area with canopy height, showed distinctly different shapes for the stands, depending on species composition and age structure. New England stand heights, obtained from foliage profiles, were not significantly different (power = 0.91) from RH100 values observed by LVIS in 2003.

Three-D forest reconstructions provide the ability to make virtual structural measurements that also match field measurements very well. Merging point clouds from overlapping scans produces the 3-D reconstruction, which can be used to measure individual DBH (R2 = 0.97, 0.99, n = 20, 15 trees, two Sierra Nevada sites) and tree height (R2 = 0.98, 0.98, n = 18, 16 trees, compared to LVIS RH100 values). A second-generation instrument, the Dual-Wavelength Echidna Lidar (DWEL), is currently under development by the Echidna Lidar Team at Boston University with NSF support. This research was supported by NASA grants NNG06GI92G and NNX08AE94A and NSF grant DBI-0923389.

Presentation Type:  Poster

Session:  Other   (Tue 11:30 AM)

Associated Project(s): 

• Strahler, Alan: Retrieval of Vegetation Structure and Carbon Balance Parameters Using Ground-Based Lidar and Scaling to Airborne and Spaceborne Lidar Sensors ...details

Poster Location ID: 282