Researchers studied the transpiration rates of seven different types of poplar trees in Gaomi city, China. They found that the daily transpiration rates of the trees followed a similar pattern to the opening and closing of their stomata. The trees with the highest daily transpiration rates were TrI-107, Tr NL95, and Tr L35. The relationship between transpiration rate and stomatal conductance was very strong. The factors that influenced transpiration rates the most were humidity, temperature, and wind speed.