An Evapotranspiration: is Evapotranspiration is the process through which plants Release water to the surrounding air, dissipating ambient heat. According to the Department of Energy' s Lawrence Berkeley National Laboratory, a single mature and properly watered tree with a crown of 30 feet can "evapotranspire" up to 40 gallons of water in a day. Tree planting on a large scale can reduce surrounding air temperatures.