Resumo

MONACO, M  e  LACLAU, P. Caracterización de la oferta de recursos forestales del partido de Balcarce, provincia de Buenos Aires. RIA. Rev. investig. agropecu. [online]. 2013, vol.39, n.2, pp.149-161. ISSN 1669-2314.

The forestry potential for the south-eastern region of Buenos Aires province is high, although the current forest lands are still unbound and characterize as sparse, fragmented and lacking of management. This is the context for plantations (commercial/ non commercial) of the Balcarce county, accounting for about 1.100 ha of standing tree patches in 2002, 75% of commercial species. For land use planning and forest management it is necessary to assess the composition, state and distribution of the present tree plantations. The objectives of this study were to (1) elaborate thematic maps of the different types of forest stands of Balcarce to a recognition scale and (2) characterize the commercial forest supply in terms of area, structure and composition. By visual analysis of Digital Globe® satellite imagery, forest units (classified as commercial stand, forest shelter, forest windbreak, protective forest and forest park) were identified and geographically positioned with dots or vectors (polygons). Thematic layers of the Atlas Digital del Partido de Balcarce were used as a cartographic support. The units were identified by means of interpretation techniques, using photographic features. Additional secondary information helped to include some recently afforested polygons (not identifiable in the images). For field supervision strip transects along highways and roads were transited, covering 5,400 ha (1.3% of the county), recognizing the botanic genus, developing stage and relative density of the tree stands of the commercial class. The resulting forest map was structured as a Geographic Information System, accounting for 5,711 forest units of the 5 categories. The area of the commercial forest polygons amounted 3,017 ha of different sub-classes. Distinctive distribution patterns were observed when correlating the forest map with some other map layers, some associated to water streams, topography, size of land parcels or proximity to roads or urban centres. There were not found significant differences (p<0.05) between visually digitalized and observed units. The field supervision help to unbundle commercial forest class, into mixed (29%, 254 ha) and pure (71%, 624 ha) stands. Finally, the noting utility of visual analysis of Google Earth® imagery for remote forest surveys to provide accurate results to a regional scale with simple tools was emphasized. Also, error sources of the method were cited. The above mentioned software, free-accessible and easy to handle, contributes to the dissemination of the forest map for direct use by different stakeholders. The study also contributed to (qualitatively) know the forest assets of the Balcarce county and to provide an estimation of the current area of commercial forest, both achievements valuable for public policy design and implementation.

Palavras-chave : Forest classes; Visual analysis; Forest map; Commercial stands.

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