Leaf and shoot morphology change with height in the crown of a tree. Among 12 evergreen conifer species in the western United States, stand productivity is higher for species with greater leaf/shoot plasticity along the vertical light gradient. Of these, coast redwood (Sequoia sempervirens), has the greatest plasticity and highest productivity. The vertical change in leaf/shoot morphology of S. sempervirens is determined by the light environment up to ca. 70-80 m and apparently constrained by hydrostatic limitation near the tree top. However, recent measurements of leaf-water relations characteristics suggest that the tree-top leaves are not water stressed. Crown reiteration in the form of epicormic shoot production may be an important mechanism that maintains physiological function in the crown of large, old trees by improving hydraulic architecture, reducing maintenance respiration, and preventing meristem aging.