effects of tree height on branch hydraulics leaf structure and gas exchange in california redwoods we examined changes in branch hydraulic leaf structure and gas exchange properties in coast redwood sequoia sempervirens and giant sequoia sequoiadendron giganteum trees of different sizes leafspecific hydraulic conductivity kl increased with height in s sempervirens but not in s giganteum while xylem cavitation resistance increased with height in both species despite hydraulic adjustments leaf mass per unit area lma and leaf carbon isotope ratios delta13c increased and maximum massbased stomatal conductance gmass and photosynthesis amass decreased with height in both species as a result both amass and gmass were negatively correlated with branch hydraulic properties in s sempervirens and uncorrelated in s giganteum in addition amass and gmass were negatively correlated with lma in both species which we attributed to the effects of decreasing leaf internal co2 conductance gi specieslevel differences in wood density lma and areabased gas exchange capacity constrained other structural and physiological properties with s sempervirens exhibiting increased branch water transport efficiency and s giganteum exhibiting increased leaflevel wateruse efficiency with increasing height our results reveal different adaptive strategies for the two redwoods that help them compensate for constraints associated with growing taller and reflect contrasting environmental conditions each species faces in its native habitat