© 2002 Heron Publishing—Victoria, Canada
Universal scaling in tree and vascular plant allometry: toward a general quantitative theory linking plant form and function
from cells to ecosystems
Brian J. Enquist (1)
1. Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA (benquist@u.arizona.edu) / Received December 17, 2001; accepted July 7, 2002; published online October 1, 2002
Summary
A general theory of allometric scaling that predicts how the proportions of vascular plants and the characteristics of plant
communities change or scale with plant size is outlined. The theory rests, in part, on the assumptions of (1) minimal energy
dissipation in the transport of fluid through space-filling, fractal-like, branching vascular networks; and (2) the absence
of scaling with plant size in the anatomical and physiological attributes of leaves and xylem. The theory shows how the scaling
of metabolism with plant size is central to the scaling of whole-plant form and function. It is shown how allometric constraints
influence plant populations and, potentially, processes in plant evolution. Rapidly accumulating evidence in support of the
general allometric model is reviewed and new evidence is presented. Current work supports the notion that scaling of how plants
utilize space and resources is central to the development of a general synthetic and quantitative theory of plant form, function,
ecology and diversity.
Keywords:
diversity, energy dissipation, evolution, fractal networks, metabolism, space-filling.
