Is bigger better in plants? The hydraulic costs of increasing size in trees

Three new studies suggest that tall trees experience increased hydraulic stress in drawing water from the soil into their canopies. They adjust to this by various homeostatic mechanisms, such as reducing the leaf area/conducting stem ratio. These mechanisms partly mask the hydraulic consequences of increased tree height in some measures of plant-water interactions, and have implications for the hydraulic limitations hypothesis and the fractal networks transport hypothesis.