The study looked at how Ormosia pinnata leaves exchange gases, open stomata, and use water efficiently during summer. They found that the leaves had two peaks in photosynthesis and transpiration rates each day. Photosynthesis was mainly affected by light, while transpiration was influenced by light, temperature, and humidity. Stomata were more sensitive to humidity than light or temperature. Stomata and photosynthesis responded differently to the environment. Water use efficiency was highest in the morning and linked to stomatal conductance during the day.