Empleo de la teledetección en el análisis de la deforestación tropicalel caso de la reserva forestal de Ticoporo (Venezuela)

Abstract

This study presents a simple multi-temporal analysis methodology to monitor the deforestation process in the Tipocoro Reserve (Venezuela). A series of air photos (1962) plus four satellite images from 1972, 1989, 1993 and 1997 were used. A vegetation type map was obtained from photo-interpretation, which was later reclassified into just two categories: forests and crops. The satellite images were also classified into these two same categories by establishing thresholds for each of their vegetation indices (NDVI). A cross tabulation was carried out for each pair of classified images in chronological order (1962-1972, 1972-1989, 1989-1993, and 1993-1997) plus a pair corresponding to the first and last date (1962- 1997), in order to determine changes during this time period. The total deforestation can be estimated in approximately 80,000 ha, which accounts for 60% of the study area. The method used proved to be very useful for deforestation monitoring purposes and can be implemented by forestry management officials to control its effects. Finally, a simple analysis was carried out to study the spatial trends in the study area throughout this period. Changes in the study area’s patches were analysed taking into account the number of polygons, density, average size and diversity. Results showed that spatial diversity increased (higher fragmentations, since the original area is parceled out), in spite of the decrease in vegetation diversity resulting from losses in forested cover area.