Tree physiology is a branch of plant physiology that focuses on the study of how trees function, including how they obtain and use water, nutrients, and energy. This field of research investigates the various physiological processes that occur within trees, such as photosynthesis, respiration, and transpiration. Researchers in this field also study how trees respond to environmental factors such as light, temperature, and water availability. Overall, tree physiology helps us better understand the biology and ecology of trees, as well as their role in the larger ecosystem.