Agradecimentos: Funding for this study was provided by the Fundação de Amparo à Pesquisa do Estado de São Paulo – FAPESP, Brazil (Thematic Project number 08/04490-4 and Doctorate Scholarship 13/21231-0). The burnings in Cruzeiro do Sul and Rio Branco were conducted under permission of the Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq and Instituto de Meio Ambiente do Acre – IMAC, Brazil. The burning in Candeias do Jamari was conducted under permission of CNPq and Secretaria de Estado do Desenvolvimento Ambiental de Rondônia – SEDAM. The authors are grateful to Mr. Antônio Abel dos Santos, owner of Sítio Belo Desejo, where the field burning of Cruzeiro do Sul was conducted. The authors also thank Prof. Luiz Fernando Costa Nascimento for his guidance on the statistical analysis Ver menos

Abstract: Forests represent an important role in the control of atmospheric emissions through carbon capture. However, in forest fires, the carbon stored during photosynthesis is released into the atmosphere. The carbon quantification, in forest burning, is important for the development of measures for its control. The aim of this study was to quantify CO2 and CO emissions of forest fires in Western Amazonia. In this paper, results are described of forest fire experiments conducted in Cruzeiro do Sul and Rio Branco, state of Acre, and Candeias do Jamari, state of Rondônia, Brazil. These cities are located in the Western portion of the Brazilian Amazon region. The biomass content per hectare, in the virgin forest, was measured by indirect methods using formulas with parameters of forest inventories in the central hectare of the test site. The combustion completeness was estimated by randomly selecting 10% of the total logs and twelve 2 × 2 m2 areas along three transects and examining their consumption rates by the fire. The logs were used to determine the combustion completeness of the larger materials (characteristic diameters larger than 10 cm) and the 2 × 2 m2 areas to determine the combustion completeness of small-size materials (those with characteristic diameters lower than 10 cm) and the. The overall biomass consumption by fire was estimated to be 40.0%, 41.2% and 26.2%, in Cruzeiro do Sul, Rio Branco and Candeias do Jamari, respectively. Considering that the combustion gases of carbon in open fires contain approximately 90.0% of CO2 and 10.0% of CO in volumetric basis, the average emission rates of these gases by the burning process, in the three sites, were estimated as 191 ± 46.7 t ha-1 and 13.5 ± 3.3 t ha-1, respectively Ver menos