GEOENVIRONMENTAL CHARACTERIZATION AND LAND USE IN THE PURUS NATIONAL FOREST, WESTERN AMAZON, BRAZIL: A CONTRIBUTION TO THE MANAGEMENT PLAN

The Purus National Forest (PNF) is a Conservation Unit (CU) located in the Amazon State, Brazil, and comprises 256 000 ha of highly preserved rainforest as well as several traditional population settlements. The objectives of this work were: (i) the physical characterization of the CU; (ii) mapping of current land uses at different scales and; (iii) the proposal of macro management zones. Interpretations of orbital and sub-orbital images, aerial photographs as well as field surveys were carried out according to the Brazilian Methodological Itinerary for Elaboration of National Forest Management Plans (Brasil, 2003). Three Geoenvironmental Units were mapped (1:100 000 scale): Dissected plateaux on Latossolos and Argissolos; Slopes and terraces on Argissolos and Aluvial plains with Neossolos Fluvicos and Gleissolos. Highly weathered, nutrient-poor soils with high Al 3+ levels occupy most of the area. Along the Purus River, lowlands (varzeas) with eutric soils constitute important agricultural areas. Five macro management zones were proposed: two protection zones (Restricted and Conservation) and three production zones (Residential, Forestry Management and Agricultural). The detailed study (1:20 000) along the igarape Mapia allowed the identification and mapping of seven land use units: young and old regeneration areas (capoeiras), pastures, agriculture, residences, yards and agroforestry systems. In total, only 0.5 % of the NF is under anthropic influence, which is concentrated along the the Igarape Mapia.