SFI President Geoffrey West and External Professors Brian Enquist and Jim Brown have proposed a quantitative theory for the structure and dynamics of forests, such that the entire forest can be described mathematically and behaves structurally and functionally like a scaled version of the branching networks in the largest trees. How trees use resources, fill space, and grow are manifestations of how trees’ xylem elements are bundled together to conduct water and nutrients. These scale up to determine emergent properties of diverse forests. The theory should apply to a wide range of forests despite large differences in abiotic environment, species diversity, and taxonomic and functional composition. See “A General Quantitative Theory of Forest Structure and Dynamics” and “Extensions and Evaluations of a General Quantitative Theory of Forest Structure and Dynamics” by G. B. West, B. J. Enquist, and J. H. Brown, Proceedings of the National Academy of Sciences USA 106(17): 7040-7045 and 7046-7051 (parts 1 and 2 of a three-part series).