Branch thinning and the large-scale, self-similar structure of trees

Lars Hellström, Linus Carlsson, Daniel S. Falster, Mark Westoby, Åke Brännström

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    2 Citations (Scopus)
    8 Downloads (Pure)


    Branch formation in trees has an inherent tendency toward exponential growth, but exponential growth in the number of branches cannot continue indefinitely. It has been suggested that trees balance this tendency toward expansion by also losing branches grown in previous growth cycles. Here, we present a model for branch formation and branch loss during ontogeny that builds on the phenomenological assumption of a branch carrying capacity. The model allows us to derive approximate analytical expressions for the number of tips on a branch, the distribution of growth modules within a branch, and the rate and size distribution of tree wood litter produced. Although limited availability of data makes empirical corroboration challenging, we show that our model can fit field observations of red maple (Acer rubrum) and note that the age distribution of discarded branches predicted by our model is qualitatively similar to an empirically observed distribution of dead and abscised branches of balsam poplar (Populus balsamifera). By showing how a simple phenomenological assumption—that the number of branches a tree can maintain is limited—leads directly to predictions on branching structure and the rate and size distribution of branch loss, these results potentially enable more explicit modeling of woody tissues in ecosystems worldwide, with implications for the buildup of flammable fuel, nutrient cycling, and understanding of plant growth.

    Original languageEnglish
    Pages (from-to)E37-E47
    Number of pages11
    JournalAmerican Naturalist
    Issue number1
    Early online date1 Jul 2018
    Publication statusPublished - Jul 2018

    Bibliographical note

    Copyright 2018 by University of Chicago Press. Originally published in American Naturalist, 192(1), pp. E37-E47.


    • branching structure
    • self-similarity
    • tree architecture
    • wood litter


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