NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Primary and Secondary Controls on Measurements of Forest Height Using Large-Footprint Lidar at the Hubbard Brook LTEROn September 26, 1999, we mapped canopy structure over 90% of the Hubbard Brook Experimental Forest in White Mountain National Forest, New Hampshire, using the Laser Vegetation Imaging Sensor (LVIS). This airborne instrument was configured to emulate data expected from the Vegetation Canopy Lidar (VCL) space mission. We compared above ground heights of the tallest surfaces detected by lidar with average forest canopy heights estimated from tree-based measurements in or near 346 0.05 ha plots (made in autumn of 1997 and 1998). Vegetation heights had by far the predominant influence on lidar top heights, but with this large data set we were able to measure two significant secondary effects: those of steepness or slope of the underlying terrain and of tree crown form. The size of the slope effect was intermediate between that expected from models of homogeneous canopy layers and for solitary tree crowns. The first detected surfaces were also proportionately taller for plots with more basal area in broad leaved northern hardwoods than for mostly coniferous plots. We expected this because of the contrast between the shapes of cumulative distributions of surface area for elliptical or hemi-elliptical tree crowns and those for conical crowns. Correcting for these secondary effects, when appropriate data are available for calibration, may improve vegetation structure estimates in regional studies using VCL or similar lidar data sources.
Document ID
20000097953
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Knox, Robert G.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Blair, J. Bryan
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Schwarz, Paul A.
(Cornell Univ. Ithaca, NY United States)
Hofton, Michelle A.
(Maryland Univ. College Park, MD United States)
Dubayah, Ralph
(Maryland Univ. College Park, MD United States)
Smith, David E.
Date Acquired
August 19, 2013
Publication Date
January 1, 2000
Subject Category
Earth Resources And Remote Sensing
Meeting Information
Meeting: 85th Annual Meeting of the Ecological Society of America
Location: Snowbird, UT
Country: United States
Start Date: August 6, 2000
End Date: August 10, 2000
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

There are no available downloads for this record.
No Preview Available