Open AccessGrowth and hydraulic (not mechanical) constraints govern the scaling of tree height and mass
Author(s) -
Karl J. Niklas,
Hanns Christof Spatz
Publication year - 2004
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0405857101
Subject(s) - scaling , tree (set theory) , stability (learning theory) , range (aeronautics) , ecology , basal area , scaling law , scale (ratio) , mathematics , biology , evolutionary biology , statistical physics , physics , combinatorics , computer science , geometry , materials science , machine learning , composite material , quantum mechanics
The size-dependent variations of plant height L and mass M with respect to basal stem diameter D are important to the analysis of a broad range of ecological and evolutionary phenomena. Prior examination of some of the world's largest trees suggests that the scaling relationships L alpha D(2/3) and M alpha D(8/3) hold true, ostensibly as functional adaptations for mechanical stability. This concept remains engrained in the literature in the form of null hypotheses (or predictive models), despite numerous examples showing that the 2/3 and 8/3 rules are violated by small and intermediate-sized plants. Here, we present a growth-hydraulic model that provides more accurate and biologically realistic predictions of L and M. This model also sheds light on why L, D, and M scale differently across species and habitats as a result of differences in absolute size.