Can you rescue a rainforest? The answer may be yes

Another success came when Cornell student Jackeline Salazar did a survey of the plants that moved into the planted areas. She counted understory species, plants that took up residence in the shade of the new trees. Most plots had over a hundred of these species, and many of the new species are ones that also live in nearby remnants of the original forests.

Together, these results mean that mixed-species plantings can help to jump-start a rainforest. Local farmers who use the same approach will control erosion of their land while creating a forest that can be harvested sustainably, a few trees at a time.

"By restoring forests we're helping to control erosion, restore quality forests that belong there, and help the quality of life of the local people," says Leopold.

That quality-of-life issue is drinking water. It's in scarce supply where forests have been destroyed, since without tree roots to act as a sort of sponge, rain water runs off the hillsides and drains away.

Erosion is also out of control. "You might drive on a dirt road one year, and then come back the next to find it's a gully over six feet deep," says Leopold. "It's a very serious problem."

Does the experiment's success mean that rainforests will one day flourish again? Fully rescuing a rainforest may take hundreds of years, if it can be done at all.

"The potential for the forest being able to come back is debatable," Leopold says, but the results are promising.

"I'm surprised," he said. "We're getting an impressive growth of new forest species." After only ten years, plots that began with a few species are now lush forests of hundreds. Who knows what the next few decades - or centuries - might bring?

The findings were published in the March 2008 issue of Ecological Restoration.