Tropical Tree Allometry: Variation, Theory, and Application

Tree allometry, the relationship between different tree dimensions such as diameter, height, and crown area, is important for understanding physiological and structural constraints on trees, such as growing tall enough to access light while resisting wind damage. Understanding these relationships is also essential for calculating tree and forest biomass. Data from Barro Colorado Island (BCI) have shown that while crown size increases as a power of diameter, height approaches an asymptote as diameter increases. Diameter-to-height allometries deviate from predictions of metabolic theory, especially for large trees, whereas diameter-to-crown area allometry is consistent with predictions from theory. Remote sensing has been used to delineate tree height and crown sizes, allowing the development of allometric relationships derived from remote sensing imagery. The extensive species-level data on allometry for BCI have shown how allometry varies across functional groups and with other species traits, enabling vegetation models to better represent forest structure and allocation.