Field experiment on the oasis effect of urban areas using potted plants

Field experiment using pot plants was performed in summer to clarify the oasis effect in urban areas. Two hundred tree potted plants were divided into three groups; they are ‘isolated plant’, ’sparse canopy’, and ‘dense canopy’. The potted plants of these three groups are placed on the concrete flat space at intervals of 6m, 1m, and 0.5m, respectively. Fifty-five potted plants were selected for measurement of the amount of daily evaporation. We supplied them with water at the start of measurements in order to exclude the effect of water content of soil. From the measurement results for twenty-eight days, it is observed that the evaporation rate of isolated plant is one and a half times larger than that of center of dense canopy.