Changes like the shift of tropical forests into savannah in the Amazon highlight the potential for deforestation to drive ecosystems past potentially irreversible tipping points. Reforestation may avert or delay tipping points, but its success depends on the degree to which secondary and primary forests are substitutes in the production of ecosystem services. This article explores how deforestation, reforestation and substitutability between forest types affect the likelihood that a forest system will cross a tipping point. Efforts to ensure that secondary forests better mimic primary forests only yield a small improvement in terms of delaying ecosystem collapse. The most significant effects on tipping points arise from an increase in the relative costs of clearing primary forests or a decrease in the costs of protecting land tenure in secondary forests. Our results highlight the importance of the latter, which are often ignored as a policy target, to reduce the risk of ecosystem collapse.
