Flames in the Amazon forest: carbon emissions go up

WHRC (11971 Byte)IPAM (3646 Byte)

 

 

 

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 Belém, 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 (www.whrc.org or www.ipam.org.br). 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 program1. 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 Marabá south to Redenção, Pará 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 studies 2, 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 Marabá and Redenção 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.

 

1 Amazonia: Desflorestamento 1995-97. 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


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