Secondary forest detection in a neotropical dry forest landscape using Landsat 7 ETM+ and IKONOS imagery

We integrate forest structure and remotely sensed data for four Successional stages (pasture, early, intermediate, and late) of a tropical dry, forest area located in the Sector Santa Rosa of the Guanacaste Conservation Area in northwestern Costa Rica. We used a combination of spectral vegetation indices derived from Landsat 7 ETM+ medium resolution and IKONOS high-resolution imagery. The indices (using the red and near-infrared hands) simple ratio and normalized difference vegetation index separated the Successional stages well. Two other indices using mid-infrared bands did not separate successional stages as well. In a comparison of the successional stages with chronological age, there was no separability in the spectral reflectance among different age classes. Successional stages, in contrast, showed distinct groups with minimal overlap. We also applied a simple validation in another dry forest located in the Palo Verde National Park in the province of Guanacaste, Costa Rica, with reasonably good results.