Recent decades have been characterized by increasing temperatures worldwide, resulting in an exponential climb in atmospheric evaporative demand (i.e. vapor pressure deficit, VPD). Temperature and VPD have been identified as increasingly important drivers of plant functioning in many terrestrial biomes, including being major contributors in recent drought-induced tree mortality. Despite this, few studies have isolated the physiological effects of rising evaporative demand vs. temperature on plants, limiting our ability to anticipate future impacts on terrestrial ecosystems. Our objectives are to use experimental manipulation of temperature and VPD to detect the individual and combined effects of high temperature and VPD on plant carbon and water relations.