Constraints on modelling the deforestation and degradation of tropical open woodlands

Ecosystem heterogeneity and lack of data on areas and deforestation rates h ave constrained the modelling of deforestation in tropical open woodlands. Smaller and more continuous changes in ecosystem quality attributes (e.g. c anopy cover, tree density and biomass density) are best described as degrad ation, not deforestation. Suggestions are made for constructing degradation models by relaxing some assumptions of deforestation models to cope with t he multiple uses of multiple vegetation layers by multiple users. Employing biomass as a dependent variable would account for biomass reductions cause d by changes in woodland area, tree density and the biomass of retained tre es and shrubs, and overcome the problem of how to aggregate changes in wood land area and tree density. Disaggregating models by woodland type is also recommended.