Tropical forests are the world’s most diverse ecosystems and many people depend on them. However, most of the remaining tropical forest remaining today is regenerated forest on abandoned crop fields. Understanding the process of forest regeneration is essential to evaluate the extent to which biodiversity and critical ecosystem functions (like productivity and nutrient cycling) are maintained. I studied the first 3 decades of tropical forest recovery in Mexico, in terms of plant functional traits and ecosystem functioning. I demonstrated that, due to changing environmental conditions and competitive pressures that plants face, regenerating forests increase rapidly in diversity and change in composition of plant functional characteristics. Results indicated that while key ecosystem functions recover, biodiversity and plant functional characteristics are not the main drivers, unlike commonly expected. Unassisted recovery of tropical forest on abandoned agricultural fields can be fast and potentially contributes considerably to maintenance of biodiversity and ecosystem functions.