Agua Salud Project Panama Canal Watershed (IMAGE) Smithsonian Tropical Research Institute Caption Nearly 50 percent of the world's tropical forests are secondary forests that have regrown after clearing, agriculture or cattle grazing. The Agua Salud Project in the Panama Canal Watershed makes it possible for Smithsonian scientists to quantify carbon storage, runoff and biodiversity for land uses including teak and native tree species plantations. Credit Christian Ziegler Usage Restrictions Credit: Christian Ziegler License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.