Comprehensive analysis of land morphology is essential to supporting a wide range environmental studies. We developed a landforms model that identifies eleven landform units for Puerto Rico based on parameters of land position and slope. The model is capable of extracting operational information in a simple way and is adaptable to different environments and objectives. The implementation of the landforms model for land cover change analysis represents an advanced step towards understanding the expansion of urban areas and forest cover in Puerto Rico between 1977 and 1994. Expansion of urban areas has typically been associated with low and flat topographies. Forest recovery, on the other hand, has been associated with high elevations and steep slopes. Our study revealed that (1) nearly half of new developments occurred outside the plains, (2) almost all new forests occurred in mountain regions (but not on the steepest slopes), and (3) there are transitional and very dynamic landforms (the side slopes) that experience both important land development and forest recovery. Finally, we present additional examples of the land-forms model applications, including vegetation mapping, physiography, and the modeling of vertebrate habitat distributions.