Allometric regression statistics for 285 North American tree species

Scaling patterns in plants have long interested biologists, particularly
whether different species share similar patterns of growth, and whether
differences in growth trajectories depend on plant size.  Using
8,794,737 measurements for 285 species from the U.S. Forest Inventory and
Analysis database, we test several predictions emerging from a recently
published “flow similarity” model for plant growth and allometry. We show
that the model’s predicted curvature for intraspecific relationships
between height, DBH and biomass is found in 88.1% of examined cases, and
empirical slopes fall as predicted between the elastic similarity and flow
similarity predictions in 71.1% of cases. We also find a strong size
dependence in observed intraspecific allometric exponents, with large
species, particularly gymnosperms, converging near the expectation for
elastic similarity, and the central tendency among small species
approaching the expectations for flow similarity in most cases. Our
results support the idea that differences in growth patterns across plant
species depend on plant size and their attendant hydraulic and/or
biomechanical demands and helps to delineate the bounds of the theoretical
morphospace in which they occur.