Studies designed to predict how plants and trees will react to rising temperatures have consistently underestimated those responses, with the actual flowering and leafing of plants advancing far more rapidly than most experiments forecast. That is the conclusion of new research by Canadian and U.S. scientists who analyzed 50 plant studies on four continents. By looking at field records of the timing of plant events, the researchers found that leafing and flowering advance by nearly a week for every 1 degree C rise in temperature. But when scientists create experimental plots and heat them to simulate future temperature increases, their predictions usually under-predict plant responses to global warming by at least four-fold, according to the study, published in an online issue of Nature. The timing of annual plant events, known as phenology, has major implications for crop pollination, water supplies, and ecosystem health. The researchers said that plant experiments need to be better designed to reflect the actual impact of future warming.