Recuperation of a degraded Amazonian landscape: forest recovery and agricultural restoration

Ranching and logging operations are transforming the moist tropical forests of an eastern Amazonian landscape into a mosaic of pastures and regrowth forests. The new ecosystems of this region are agriculturally unproductive, biologically impoverished, and far more flammable than the mature forests they replace. In the absence of fire, the forest regrows on abandoned sites, accumulating biomass and species at a rate that is inversely related to the intensity of use prior to abandonment. Forest regrows slowest on those rare abandoned pastures that were once scraped with bulldozers. The grass- and shrub-dominated old fields that form on some of these sites resist forest regrowth because of numerous barriers to tree establishment and growth. Knowledge of these barriers provides a basis for developing inexpensive techniques to restore agricultural productivity in old fields by implanting tree-based agricultural systems or to restore forest regenerative capacity in old fields by establishing trees that attract seed-carrying animals and ameliorate harsh environmental conditions. These restoration techniques will be needed over large areas of Amazonia if current attempts to reform degraded pastures fail. -from Authors