Acacia Tree (IMAGE) Princeton University Caption Princeton University researchers might have finally provided a solution to the ecological riddle of why tree abundance on Africa's grassy savannas diminishes in response to heavy rainfall despite scientists' expectations to the contrary. The researchers found that the ability of grasses to more efficiently absorb and process water gives them an advantage over trees such as the acacia (pictured). Credit (Photo by Kev Moses, Licensed under <a target="_blank"href="https://creativecommons.org/licenses/by/2.0/">CC BY 2.0</a>.) Usage Restrictions Respect the terms of the license: <a target="_blank"href="https://creativecommons.org/licenses/by/2.0/">CC BY 2.0</a> 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.