Deforestation in the southern portion of the Roraima State: distribution with respect to INCRA settlement projects and distance from major highways (BR-174 and BR-210)

• Published in: Acta amazonica 2012-06, Vol.42 (2), p.195-204
• Main Authors: Barni, P E, Fearnside, P M, de A Graca, PML
• Format: Article
• Language: Portuguese
• Subjects: Buffers; Data processing; Deforestation; Forests; Geographic information systems; Highways; Information systems; Invasions; Landsat; Logging; Migration; Public policy; Spreading
• ISSN: 0044-5967

Deforestation in the Amazon currently represents one of the greatest environmental issues in Brazil, and stopping this process requires public policies based on understanding the forces that control the forest loss in different parts of Amazonia. We evaluated deforestation in the southern portion of Roraima State using a Geographical Information System (GIS) to delineate buffers along each of the two main highways that cross the region: BR-174 and BR-210. Each buffer was 20 km wide and was divided into eight strips 2500 m in width. The study covered the 2001-2007 period using annual deforestation data from PRODES vector files and visual analysis ofTM Landsat 5 imagery. We also used shape files of roads and settlement projects in the southern part of Roraima coupled with field observations. Deforestation in the period was strongly related to the availability of roads and to the number of families present in the settlement project. The occurrence of deforestation was highest in the area of the BR-210 where large landowners and land invasions were present. The logging center on the BR-174 may have influenced the formation of small clearings in the Rorainopolis city neighbor. Predatory logging and new land occupations by both small and large landholders are spreading quickly in a disorderly fashion. This situation has high potential for forest loss since migration is expected to increase if Roraima is connected to the "Arc of Deforestation" by reopening the BR-319 Highway, which would connect Manaus to Porto Velho.Original Abstract: O desmatamento na Amazonia representa, atualmente, um dos principais problemas ambientais do Brasil. A contencao deste processo requer politicas publicas baseadas no entendimento das forcas que controlam, aceleram e desaceleram a perda de floresta. Para avaliar ocorrencias de desmatamento no sul do Estado de Roraima foram utilizados dois buffers de 20 km de largura subdivididos em oito faixas de 2500 metros ao longo das duas principais rodovias da regiao: BR-174 e BR-210 em um ambiente de Sistema de Informacoes Geograficas - SIG. O periodo analisado foi entre 2001 e 2007, sendo utilizados dados de desmatamento do PRODES e analises visuais em imagens TM Landsat 5. Tambem foram utilizados arquivos shapefile da malha viaria e de Projetos de Assentamento (PAs) do Sul do Estado de Roraima, junto com observacoes de campo. Os resultados mostraram que os desmatamentos do periodo estao fortemente relacionados com a disponibilidade de estrad