Humans have cut down large areas of tropical forests around the world. Scientists were curious if these forests could grow back without tree planting or other human help.

Scientists modeled forest regeneration using satellite photos and machine learning. Their model also used other factors that affect forest regrowth. For example, rainfall, fire frequency, and the distance from the edge of standing forest.
Using this model, scientists suggest that 215 million hectares (531 million acres) of degraded and deforested land could regenerate naturally in the tropics. This is an amount of forest roughly equal to the size of Saudi Arabia.
Brazil, China, Colombia, Indonesia, and Mexico appear to be important countries where natural forest regeneration could occur.

Forests can regrow, but how long they last is up to people. Matt Fagan from the University of Maryland is one of the researchers involved in the study. Some of Matt Fagan’s research in Costa Rica showed that people had cleared 50% of regrown forests within 20 years in the team’s study area.
“The only way a young forest sticks around is if local people are on board with letting that young forest stick around,” Matt Fagan said.
David Brown adapted this story for Mongabay Kids. For more on this story, read the original article by John Cannon, published on Mongabay News.