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Related Web Sites:
Industry Links:
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Spotlight: Forestry Applications
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Our spotlight this month is on the applications of airborne laser mapping in the forestry sector. Forestry was one of the first areas
investigated as a potential commercial application of airborne laser mapping since accurate information on the terrain and topography
beneath the tree canopy is extremely important to both the forestry industry and natural resource managers. Accurate information on tree
heights and densities is critical information that is also difficult to obtain using conventional remote sensing techniques. Airborne
laser technology, unlike radar or satellite imaging, can simultaneously map the ground beneath the tree canopy as well as the tree heights
making it a unique tool in this area.
Graphic courtesy of Michael Lefsky
Post-processing of lidar data allows the individual laser returns to be analysed and classified as vegetation or ground returns allowing
DTMs of the bare ground to be generated or accurate representative tree heights to be calculated. Emerging techniques using full waveform
analysis of the return laser pulse to investigate details of canopy structure are also receiving greater attention as the technology gains
acceptance in this sector. Airborne laser mapping is an extremely effective tool in this area when compared to photogrammetry or extensive
ground surveys. Consequently, it is a technology that forestry companies and natural resource managers need to learn about. We hope the
following collection of links will be a starting point for those interested in learning more about these particular applications of airborne
laser mapping in the forestry industry.
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- HIGH-SCAN:
A European Research Project
High-Scan is a joint, five country research program funded by the European Union to develop and test methods for the integrated use
of high-resolution satellite imagery and laser scanner data for small-area (regional and standwise) forest inventory and mapping. Their
goals include:
- Extraction of forest attributes by the integrated use of the very high-resolution satellite imagery and laser scanner for small-area
forest inventory and mapping and the demonstration of the methods for private companies and governmental authorities.
- Evaluation of the accuracy, costs, benefits and drawbacks of the combined use of high-resolution satellite imagery and laser scanner
data.
- Evaluation/demonstration by simulation how a future space-borne instruments, such as NASA's Vegetation Canopy Lidar, can be exploited
for forest inventories.
- Comparison of the method versus other remote sensing data sources.
The objectives of the HIGH-SCAN project include the retrieval of forest attributes such as timber volume, tree species proportions,
mean tree height, stand density/basal area, structural of natural age classes, soil type and fertility classes, crown area and stand
boundaries. Drop by their web
site for more information, a list of participants, principal investigators, publication references and reports on their progress.
- Lidar
Remote Sensing of Forest Structure
Michael Lefsky of the U.S. Department of Agriculture, Forest Service, Pacific NW Research Station maintains a web site that provides
a wealth of information and related links on the work that is being done at the Forest Science Laboratory with respect to lidar remote
sensing of forest using NASA's SLICER.
The site includes interesting graphics, notes, basic information on the technology, notes on their specific applications and .pdf version
of two recent articles.
To-date their studies with SLICER have shown that very accurate estimates of stand basal area, biomass and total cover are possible
using airborne laser data in both broadleaf deciduous forests in eastern North America, and in coniferous evergreen forest in the Pacific-Northwest.
Their results also indicate that a three-dimensional approach to lidar waveforms is able to accurately characterise both biomass and
leaf area index non-asymptotically over a wide range. Furthermore, this technique can characterise aspects of the complexity of canopy
structure that have been infrequently measured, either from field or remote methods. These measurements can be directly related to indices
of forest stand structural complexity, such as those developed for old-growth forest characterisation in Douglas-fir/Western Hemlock
forests of the Pacific-Northwest. An excellent resource
site. Well worth a visit even if you are not interested in forestry.
Michael also teaches a course at Oregon State University, an Introduction
to Lidar Remote Sensing of Forests if you are interested in a more formal approach to the subject
- NASA
Will Study Forests With Laser Instruments
NASA's involvement with lidar remote sensing of forests does not end with SLICER. The Vegetation
Canopy Lidar (VCL) mission is a satellite-based lidar instrument scheduled for launch September 15th, 2000. its principal goal is
the characterisation of the three dimensional structure of the Earth, in particular canopy vertical and horizontal structure and land
surface topography. When operational, it will create the first global maps of forest vegetation. Over the course of its two year lifespan,
VCL will sample the vast majority of the Earth's closed canopy forests, collecting elevation data for canopy tops as well as the underlying
terrestrial topography. A recent online article - Laser
Instrument To Study Forest Health (Tuesday, September 21, 1999; Environmental News Network) - includes a good overview of
the program and a picture of the mock-up of the satellite.
The Laser
Vegetation Imaging Sensor (LVIS), built at NASA's Goddard Space Flight Center is an airborne test bed prototype for the VCL mission.
Flying aboard a NASA Wallops Flight Facility C-130 aircraft, LVIS began mapping eastern U.S. forests in Maryland, North Carolina, and
New Hampshire on Sept. 16 1999. Previous flights mapping California's Sequoia National Forest and over the Costa Rican rain forest have
produced the first fine-scale measurements of topography hidden beneath the forest canopy, canopy height and structure, and tropical
forest biomass using remote sensing. LVIS is getting a lot of coverage in the mainstream press. Recent online articles include:
While two recent academic publications are also available online; Modeling
Laser Altimeter Return Waveforms Over Complex Vegetation Using High-Resolution Elevation Data (Blair and Hofton) and The
Laser Vegetation Imaging Sensor: A Medium-altitude, Digitisation-only, Airborne Laser Altimeter for Mapping Vegetation and Topography
(Blair et. al.). Both are in *.pdf format.
Both the VCL and LVIS sites offer interesting background information and technical notes on their respective instruments. There is also
a commercial focus to these programs through the involvement of companies like Raytheon.
- Second
International Conference on Geospatial Information in Agriculture and Forestry
ERIM International is sponsoring this conference to focus on the latest developments in advanced geospatial data and information technologies
in agriculture and forestry. The three-day technical program to be held in Lake Buena Vista, Florida (yes, complimentary transportation
to the Magic Kingdom is included!) 10-12 January 2000, will offer more than 300 presentations in general and interactive poster sessions,
with extensive workshops, demonstrations, and exhibits of products and services. This conference will include several presentation on
the application of airborne laser mapping technology to forestry (and agriculture) including;
- Spatial Variation of Tropical Forest Structure in Relation to Remotely Sensed Laser Waveforms (Yoder and Weishampel)
- Comparison of Large Footprint and Small-Footprint LIDAR: Functionality, Capabilities and Uses (Means)
- Estimating Forest Vegetation Biomass Using Airborne Lidar Measurements (Popescu et. al.)
- Assessment of High-Performance LIDAR for Determination of Northwest Forest Conditions (Renslow)
- A New LIDAR System and Its Potential Uses in Forestry Applications (Wang and DeLoach)
- Multiple Return Lidar Data for Use in Forest Assessment and Inventory in the South-eastern United States (Wayne et. al.)
- Comparison of LIDAR and Field measurements of Loblolly Pine (Young and Evans)
A very interesting collection of topics and further evidence that airborne laser mapping is receiving more attention as a remote sensing
tool for the forest industry.
- Spatial
Information Technologies Laboratory (SITL) at Mississippi State University
Three sensors with excellent potential for providing information on stand height, density, structure, and species composition are being
evaluated at SITL. The three sensors are a multispectral frame camera (operated by Space Remote Sensing Center, Stennis Space Center,
Mississippi); an airborne lidar system (developed and operated by Photo Science, Inc., Gaithersburg, Maryland - now EarthData); and
the CARTERRA 1 satellite operated by Space Imaging/EOSAT, Thorton, Colorado. Details are available online
along with a good description of the processing steps required to create stand maps from the three sensors.
- Development
of the kNN Method For Estimating Forest Stand Characteristics
There is also work being done at the Swedish University of Agricultural Sciences' Department
of Forest Resource Management and Geomatics and SkogForsk, "The Forest Management Project" aiming at further improving
forest management techniques using airborne laser mapping.
- Finally, there are several excellent examples of lidar applications to forestry available online through the Geospatial
Analysis and Modeling of Ecological Systems (GAMES) laboratory in the Department of Biology at the University of Central Florida,
including:
- TopoSys - An Example DEM in a Forest Area
Many of the survey companies in the industry have completed work in the forestry sector using airborne laser mapping so there are good
examples of data sets available either on the individual companies web sites or by request. Check our Industry
Directory for a complete list. We have chosen the TopoSys page as an example since it includes a ground picture of the area surveyed.
- For a commercial view point on the impact of airborne laser technology in the forestry sector, be sure to read our interview
with Dr. Zhekui Ma, remote sensing specialist in the Timberland Information Services division of Weyerhaeuser Paper.
- NASA
- Remote Sensing as Used for Archaeological Research
Just think what Indiana
Jones could have done with tools like these. "Very dangerous Indy; you go first!"
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