NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Modeling the Height of Young Forests Regenerating from Recent Disturbances in Mississippi using Landsat and ICESat dataMany forestry and earth science applications require spatially detailed forest height data sets. Among the various remote sensing technologies, lidar offers the most potential for obtaining reliable height measurement. However, existing and planned spaceborne lidar systems do not have the capability to produce spatially contiguous, fine resolution forest height maps over large areas. This paper describes a Landsat-lidar fusion approach for modeling the height of young forests by integrating historical Landsat observations with lidar data acquired by the Geoscience Laser Altimeter System (GLAS) instrument onboard the Ice, Cloud, and land Elevation (ICESat) satellite. In this approach, "young" forests refer to forests reestablished following recent disturbances mapped using Landsat time-series stacks (LTSS) and a vegetation change tracker (VCT) algorithm. The GLAS lidar data is used to retrieve forest height at sample locations represented by the footprints of the lidar data. These samples are used to establish relationships between lidar-based forest height measurements and LTSS-VCT disturbance products. The height of "young" forest is then mapped based on the derived relationships and the LTSS-VCT disturbance products. This approach was developed and tested over the state of Mississippi. Of the various models evaluated, a regression tree model predicting forest height from age since disturbance and three cumulative indices produced by the LTSS-VCT method yielded the lowest cross validation error. The R(exp 2) and root mean square difference (RMSD) between predicted and GLAS-based height measurements were 0.91 and 1.97 m, respectively. Predictions of this model had much higher errors than indicated by cross validation analysis when evaluated using field plot data collected through the Forest Inventory and Analysis Program of USDA Forest Service. Much of these errors were due to a lack of separation between stand clearing and non-stand clearing disturbances in current LTSS-VCT products and difficulty in deriving reliable forest height measurements using GLAS samples when terrain relief was present within their footprints. In addition, a systematic underestimation of about 5 m by the developed model was also observed, half of which could be explained by forest growth that occurred between field measurement year and model target year. The remaining difference suggests that tree height measurements derived using waveform lidar data could be significantly underestimated, especially for young pine forests. Options for improving the height modeling approach developed in this study were discussed.
Document ID
20120010376
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Li, Ainong
(Maryland Univ. College Park, MD, United States)
Huang, Chengquan
(Maryland Univ. College Park, MD, United States)
Sun, Guoqing
(Maryland Univ. College Park, MD, United States)
Shi, Hua
(ASRC Research and Technology Solutions, LLC Greenbelt, MD, United States)
Toney, Chris
(Forest Service Missoula, MT, United States)
Zhu, Zhiliang
(Geological Survey Reston, VA, United States)
Rollins, Matthew G.
(Geological Survey Sioux Falls, SD, United States)
Goward, Samuel N.
(Maryland Univ. College Park, MD, United States)
Masek, Jeffrey G.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 26, 2013
Publication Date
January 1, 2011
Publication Information
Publication: Remote Sensing of Environment
Volume: 115
Issue: 8
Subject Category
Earth Resources And Remote Sensing
Report/Patent Number
GSFC.JA.00337.2012
Funding Number(s)
CONTRACT_GRANT: KZCX2-YW-QN313
Distribution Limits
Public
Copyright
Other

Available Downloads

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