[The following is being distributed on behalf of
colleagues at the Woods Hole Research Center and IPAM -
Instituto de Pesquisa Ambiental da amazonia]
Contact Information:
Adriana Moreira
Woods Hole Research Center
+55 61 3409992 (in Brazil)
Email adriana at whrc.org
Information Bulletin for the Buenos Aires Conference
Flames in the Amazon forest: carbon emissions go up.
In May of 1998, researchers of the Instituto de
Pesquisa Ambiental da Amazonia (IPAM), a non-
governmental research institute based in Bel?m, Brazil,
and the Woods Hole Research Center (WHRC), based in
Massachusetts, predicted that approximately 400,000 km2
of forest in the Brazilian Amazon would become
vulnerable to fire during the 1998 dry season (Error!
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A recent update of this fire prediction model, using
additional rainfall data collected across the region,
shows that the unusually low amounts of rainfall in
1998 have increased the area of fire-vulnerable fire to
more than one million square kilometers, or one third
of the forests of Amazonia. These researchers
calculate that more one half of this drought-stressed
forest (700,000 km2) had depleted all available soil
water to five meters depth by the end of September!
In the first field study conducted to test this
prediction, these researchers measured the amount of
fire-vulnerable forest that actually caught fire in a
small test region in southeastern Amazonia. They
discovered that three to five thousand square
kilometers of standing forest caught fire in 1998 in
this region. This area of burned forest is one-fifth
the size of the entire forest area that is "deforested"
through clear-cutting and burning each year (average is
~19,000 km2/yr), as measured by the Brazilian
Government's very important deforestation monitoring
program. 1/ And yet, the burned forests were
documented within a very small (45,000 km2) region that
is less than one percent of the legal Amazon (5,000,000
km2). The burning of standing forests is not
currently included in the government's monitoring
program.
The study was conducted in September, 1998, in a
300 x 150 km area that extends from Marab south to
Reden?ao, Par State, in the southeastern corner of
Brazil's "arc of deforestation", near the edge of the
Amazon forest. This estimate is based upon 1,110
observations made from a low-flying airplane along an
800 km flight path that criss-crossed the region,
combined with field visits to burned and unburned
forests. Forests in which ash was observed on the
ground, or in which leaves were scorched brown from
flames, were recorded as burned. Burned forests were
recorded at 9% of the observation points.
Although this study was conducted in a region that
is highly prone to forest fires because of severe
drought, these results are of major significance for
estimates of human damages to Amazon forests, and of
carbon emissions from Amazon forests associated with
land use practices. According to recent field
studies2/, the burning of standing forest can release
10 to 80% of forest biomass to the atmosphere as heat-
trapping carbon dioxide. Therefore, the forest fires
such as those observed between Marab and Reden?ao
release large amounts of carbon dioxide to the
atmosphere that are not included in current estimates
of carbon emissions from Amazonia. Contrary to media
reports, there have been hundreds of Amazon forest
fires in 1998.
Footnotes
1. Amazonia: Desflorestamento 1995-1997. INPE/IBAMA.
1998 (http:\\www.inpe.br)
2 Holdsworth, A. R. and C. Uhl. 1997. Fire in Amazonian
selectively logged rain forest and the potential
for fire reduction. Ecological Applications 7 (2):
713-725.
Cochrane, M. A. and M. D. Schulze. In press. Fire as a
recurrent event in tropical forests of the eastern
Amazon: effects on forest structure, biomass, and
species composition. Biotropica.