Forest ecologist Daisy Dent has spent two decades studying how tropical forests rebuild themselves after destruction. At the Barro Colorado Nature Monument in Panama, she tracks plots of naturally regenerating forest, some dating back more than a century. None of the trees were planted by people. Instead, her data shows that animals are the main architects: fruit-eating creatures such as spider monkeys, bats, and parrots disperse seeds in their droppings, accounting for over 70% of tree establishment in tropical forests.
Dent's long-term records reveal why some cleared plots rebound into rich, cathedral-like canopies while others stall. In one 70-year-old patch, diverse animal seed-dispersers helped create a forest approaching the structure of ancient jungle. In another, a single tree species dominates because rodents called agoutis are nearly the only seed movers, and stubborn pasture grasses smother other seedlings. These differences matter for climate: tropical forests store roughly 40% of carbon held on land, and resilient, naturally regrown forests can lock up large amounts of carbon dioxide.
The research offers a practical playbook for restoration. A 2024 estimate in Nature suggests some 215 million hectares of forest worldwide could regenerate naturally. Dent argues that supporting animal-plant interactions—along with fungi and pollinators—is often cheaper and more effective than planting vast areas with a single tree species, which her evidence suggests can be an expensive mistake. Her work, reported by MIT Technology Review, points to a simple but powerful lesson: sometimes the best way to restore a forest is to let its invisible networks do the work.