Limitations and mechanisms of height growth in trees

Abstract

Height growth and maximum tree height vary among species as well as with site conditions. Maximum tree height is an important factor determining the outcome of competition for light, vertical stratification of the canopy, and productivity of forest ecosystems. Recent advances in canopy access techniques have allowed direct measurement of physiological processes at the tops of tall trees. These studies indicated that height grow may be limited by constraints on water transport from soil to leaf, which reduces photosynthesis of leaves and by the gravitational gradient in water potential, which constrains cell elongation in leaves and shoots. Theoretical and experimental research suggests that mechanical requirements to prevent buckling and wind damage and genetic changes due to maturation are unlikely to contribute to height-growth limitation. Further research investigating the relationships between maximum tree height and succession, crown interactions, species variation in natural stands are needed for comprehensive understanding of height growth in trees. Such knowledge could potentially be used to predict variation in productivity among various forest types.