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helped us assess the variability between analyses conducted in
the two different laboratories, and assessments of the
variation in interpretation and classification within the
laboratory. The latter was accomplished through repeated
classification trials and comparisons with classifications
performed using other data sources, such as Spot. Some
preliminary results from an accuracy assessment of our
Amazon analysis revealed an overall accuracy of 89%.
Some of these field test sites were also used for examining the
land cover change dynamics between the nearly decadal
assessments for each epoch to estimate the inter-annual
variability in deforestation rates. Annual Landsat and Spot
observations were analyzed to look at annual rates of clearing
and abandonment in an attempt to understand the land use
practices driving the deforestation. These sites are spread out
across the tropics in an aftempt to characterize many of the
more wide spread land use/land cover change dynamics
associated with tropical deforestation.
4. PRELIMINARY RESULTS
Results from the HTF Project are being prepared in
manuscripts that will be submitted to peer reviewed literature.
For this conference paper, some preliminary results are
presented. Initial results indicate that in the Amazon in 1985
there was 245,000 sq. km. of deforestation, of the deforested
area 72,300 sq. km. were in secondary growth. The suggests
an annual rate of deforestation from 1978 to 1985 of 18,000
sq. km. The secondary growth numbers highlight that almost
30% of the disturbed forest areas were in some form of
secondary growth. Figures of the extent of forest, natural non-
forest, deforestation, secondary growth, water, cloud, and
cloud shadows can be obtained from the HTF web page. For
these figures the full resolution data has been gridded to 16km
cells and shaded according to the percentage of each 16km cell
that has been deforested or in secondary growth. As part of
NASA's Working Prototype Earth Science Information
Partnership, a Tropical RainForest Information Center
(TRFIC) is under development at Michigan State University.
Through the TRFIC the broader research and policy
communities will have access to the raw and derived data
created as part of the HTF project.
The following table presents the preliminary estimates of the
extent of forest and average rate of deforestation from 1973 to
1986 for countries in Continental Southeast Asia (note that
areas are in thousands of square kilometers and rates in
thousands of square kilometers per year). The estimates are
preliminary because the analysis is not complete. In
comparison to the FAO FRA 1990 estimates, these annual
rates are slightly lower for Thailand, Cambodia and Laos,
significantly lower for Myanmar, and higher for Vietnam. The
results for Myanmar and Vietnam estimates maybe misleading
due of the several factors, including incomplete data and large
proportion of clouds over forested areas in the 1973 analysis.
Visual inspection of the areas with no-data indicate that the
Intemational Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998
actual rates were likely lower in Vietnam and higher in
Myanmar than the rates presented in this table. These
inconsistencies are being removed by our ongoing in our GIS
analyses and accuracy assessment activities. Final results will
be presented in future papers.
Cambodia 52 42
Myanmar 449 442
Laos 173 164
Vietnam 189 132
Thailand 222 170
Table 1. Preliminary Results
In addition to the new pan-tropical estimates of extent and
decadel rates of deforestation, HTF project has provided
significant insight into the operation use of high resolution
(20-100m) satellite data for monitoring tropical forests. The
lessons learned from HTF will be extremely useful for
developing pilot projects for operational monitoring systems
(e.g. IGOS Global Observation of Forest Cover).
All of the Landsat data used by the HTF project is available
from the Land Processes DAAC at the EROS Data Center.
Information on how to obtain data from the DAAC can be
found at the EDC home page
“ (http://sun1.cr.usgs.gov/landdaac/landdaac.html). The derived
products will initially be available from the Landsat Pathfinder
HTF project (http://pathfinder-www.sr.unh.edu/pathfinder) and
eventually from the TRFIC ESIP at Michigan State University.
REFERENCES
Ciais, P., Tans, P.P., Trolier, M., White, J.W.C., Francey,
R.J. 1995. A large northern hemisphere terrestrial CO2 sink
indicated by the "C/"C ratio of atmospheric CO2. Science.
269:1098-1102
FAO. 1993. Forest resources assessment 1990 - Tropical
countries. UN FAO. Rome.
Skole, D.S., Tucker, C.J. 1993. Tropical deforestation and
habitat fragmentation in the Amazon: Satellite data from 1978
to 1988. Science. 260:1905-1910.
Note: Sections of this paper were taken from the HTF Web
Page. In addition to this text, up to date results and browse
images can be obtained from the HTF web page.
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