Retrieving New England Forest Structure from a Ground-Based Lidar (EchidnaŽ)
Alan
H.
Strahler, Boston University, alan@bu.edu
(Presenting)
Curtis
E.
Woodcock, Boston University, curtis@bu.edu
Crystal
B.
Schaaf, Boston University, schaaf@bu.edu
Wenge
Ni-Meister, Hunter College of CUNY, wenge.ni-meister@hunter.cuny.edu
Glenn
Newnham, CSIRO Forest Biosciences, glenn.newnham@csiro.au
Darius
Culvenor, CSIRO Forest Biosciences, darius.culvenor@csiro.au
David
L. B.
Jupp, CSIRO Marine and Atmospheric Research, david.jupp@csiro.au
Jenny
Lovell, CSIRO Marine and Atmospheric Research, jenny.lovell@csiro.au
Xiaowen
Li, Beijing Normal University, lix@bnu.edu.cn
Tian
Yao, Boston University, tianyao@bu.edu
Feng
Zhao, Boston University, zhao26@bu.edu
Xiaoyuan
Yang, Boston University, xiaoyuan@bu.edu
Qingling
Zhang, Boston University, zql@bu.edu
Mitchell
Schull, Boston University, schull@bu.edu
Miguel
Roman, Boston University, mroman@bu.edu
Shihyan
Lee, Hunter College of CUNY, shihyanlee@yahoo.com
Zhuosen
Wang, Boston University, wangzhs@bu.edu
Yanmin
Shuai, Boston University, shuaiym@bu.edu
An under-canopy, upward-scanning, lidar field instrument, named EchidnaŽ, provides rapid, accurate, and automated measurements of forest stand structure, including tree diameters, stand basal area, stems per unit area, stand height, leaf area index, foliage profile, and foliage area volume density. The EchidnaŽ instrument, built by CSIRO Australia, directs a horizontal 1064 nm laser beam with 5 mr divergence and a pulse rate of 2 kHz to a rotating mirror at 45° incidence to scan a vertical circle, recording data from +137° to -130° zenith angles and all azumuths as the instrument revolves 180° on a tripod mount. The return signal is sampled at 2 gigasamples per second, digitizing the full scattered waveform. The shape of the return pulse distinguishes readily between hard targets (tree boles, branches) and soft targets (leaves), and also measures the distribution of canopy gaps, including within-crown and between-crown gaps. We report results from scans at stands of varying characteristics at Harvard Forest (Massachusetts), Howland Experimental Forest (Maine), and Bartlett Experimental Forest (New Hampshire). Retrievals of stand characteristics are validated by ground measurements of tree stems in a large circular plot centered on the scan position; of canopy characteristics by LAI-2000 measurements, hemispherical digital photographs; and allometric calculations.
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