Resumo

NEPSTAD, Daniel Curtis. Land-use in Amazonia and the Cerrado of Brazil. Cienc. Cult. [online]. 2024, vol.76, n.2, pp.01-22. ISSN 0009-6725.  http://dx.doi.org/10.5935/2317-6660.20240032.

The total area and annual rate of native vegetation clearing is greatest in the Cerrado region, followed by the Brazilian states of Pará, Mato Grosso, Maranhão, and Rondônia. Amazonian forest clearing proceeds most quickly where abundant natural resources (wood or land) are accessible by roads and close to markets. These regions are concentrated along the eastern and southern flanks of Amazonia, particularly in eastern Pará, Cuiabá, and Rondônia. There are still large discrepancies in estimates of annual deforestation: Landsat (Thematic Mapper-Based) mapping of deforestation in the closed canopy forests of Amazonia has not included non-Brazilian countries and is incomplete for the Cerrado biome. Amazonian deforestation was last mapped in 1994. Current estimates of Amazonian forest clearing do not include most of the forests there are affected by logging each year, which is an area (about 7000 km² yr) more than half the size of the area of annual deforestation. Logging changes forest structure and increases forest flammability. The intensity of logging ranges from one to 100 species harvest, in averages 20 m³ of wood harvested per hectare. Logging may increase dramatically in the coming years. Fire affects large but difficult to measure areas of pastureland, logged forests, secondary forests and primary forests. Forest ground fires are particularly difficult to map from satellite data. Fire is more frequent where forest clearing is taking place and where seasonal drought is more severe. The destiny of Amazonian forestland cleared for crops and cattle pastor is complex and highly variable regionally. Aerial estimates are needed for managed pastures, the graded pastures, cropland, and secondary forests for these ecosystems and functionally distinct. Most forest clearing is for pasture establishment, followed by shifting cultivation. Cattle pasture is the logical land use for both small scale and large scale rural Amazonians because cattle are easily sold or traded, and they maintain their value during inflation. Cattle pasture help secure land claims and increase land value. In the Cerrado, there has been a shift from extensive cattle grazing of natural savannas took pastures planted with African forage grasses; mechanized soybean production is the second most extensive land use. Pastures are the most important land covers for the LBA (large scale biosphere-atmosphere experiment in Amazonia) science campaign. Brazilian Amazonian experienced reduced rainfall during ENSO events. ENSO-related drought is most severe in eastern Amazonia. Amazing wide reduction in rainfall would have its greatest effect on vegetation near the border between Savannah and closed canopy forest in Rondônia, Mato Grosso, Pará, and Tocantins. The LBA campaign should be conducted in a variety of rural landscapes to capture the multiplicity of human effects on all native ecosystems, as well as the range of climatic and edaphic conditions under which these ecosystems have evolved. It should address the current (ENSO) and predicted variations in climate, and should be designed to recommend those land users that best reconcile the maintenance of ecosystems processes with socially equitable economic growth.

Palavras-chave : Cerrado; Amazônia; Desmatamento; Ocupação; Manejo.

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