New research suggests tropical forests can regenerate much faster than previously thought, as long as humans can leave them alone. The study, published in Science magazine, claims that secondary succession -- a phenomenon wherein favorable ecosystem conditions following a traumatic event allow for quick regeneration -- mean that forests could return to their former glory in only 20 years.

While other indicators of the forests' health may take longer to rebound (previous biomass could take more than 120 years to return), 78% of regrowth could be reached in the first two decades.

The study's lead author, Lourens Poorter, told the Guardian the findings were "good news" because "the implication is that, 20 years… that's a realistic time that I can think of. And my daughter can think of, and that the policymakers can think of.

The findings also suggest that forests don't need much help from humans to regrow. Simply protecting secondary forests from outside disturbance may be more helpful than tree planting interventions. According to Porter, the forest knows best: "My plea is to use natural regrowth where you can and plant actively and restore actively where you need to. There's a case-by-case approach, and this all depends on the local conditions and also on the local needs of the people because they live in these landscapes."