Three different methods (local knowledge, aerial photos, and botanical investigations) were used to document changes in woody vegetation cover in the Sahelian part of Burkina Faso. Local people had observed a general decline of woody plants that was most pronounced in valleys, and aerial photos supported this view. Local people also reported a lack of rejuvenation of many woody species, and this was confirmed by botanical data and size class distribution analysis. Together the three methods documented a diminution in density and diversity of the woody vegetation cover which, estimated from size class distributions, will continue in the nearest future. Some of the trees and shrubs that are most appreciated by local people are also sharply declining, and local societies are therefore faced with reductions in some of their most essential natural resources.