Jim Kellner, Brown University (image) Brown University Caption This is professor Jim Kellner in a Hawaiian forest. He and colleague Gregory Asner worked out a model to predict the likelihood that one a tree limb could be overtopped amid competiton for space in the canopy. Credit Courtesy Jim Kellner/Brown University Usage Restrictions with credit 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.