A study on Platycladus orientalis trees looked at how their stomata (tiny openings on leaves) respond to changes in soil water. Different levels of rain were used to control soil water content, and factors like sap flow, leaf area, and vapor pressure were measured. The results showed that when soil water increased, stomatal conductance also increased, reaching a peak in July. Stomata were most sensitive to changes in vapor pressure when soil water was between 3.7% and 7.5%. The trees could adapt to dry conditions by closing their stomata to conserve water. This study suggests that Platycladus orientalis trees have a threshold for soil water levels that helps them regulate transpiration effectively.