Tree height and interannual growth variation: Are tall trees more sensitive?

The influences of gravity and pathlength resistance on water potential suggest that as trees in mesic environments increase in height, they may become more sensitive to climatic variation. To test this idea, we compared patterns of ring width variation of redwood (Sequoia sempervirens) trees of three different height classes (60, 90, and 110 meters) cored at tree base, base of live crown, and tree top. We hypothesized that: 1) tops of taller trees have greater interannual growth variation than the tops of shorter trees, and 2) within height classes, tree tops have greater growth variation than the base of the crown and tree base. We found: 1) Interannual variation in ring increment did not differ (p = 0.48) among tops of trees of different heights, although there was a trend for increasing variation in taller trees, 2) Trees in the tallest and intermediate height classes had significantly greater growth variation at the base of the live crown than trees in the 60 m height class (p < 0.04), and, 3) within height classes, growth variation did not differ among the tree top, base of crown and tree base. Large tree-to-tree differences in growth variation indicate a need for increased sample size and that crown or stand level disturbances, as well as climatic factors, may influence interannual growth in our study trees. We conclude that dendrochronology of tall trees may provide a new tool for climatic reconstructions and for understanding the nature of limits to tree height and size growth.