Original title: A multiscale theory based on metabolic scaling connects forest dynamics to tree-size distributions
Christian Grilletta, Tommaso Anfodillo, Gaia Pasqualotto, Samir Suweis +3 · August 2026
Ecologists know that tree size, abundance, and resources follow strict mathematical patterns, but they lack a clear explanation for how daily forest processes create them. To solve this, researchers built a model of forest dynamics. It tracks seed dispersal, growth limited by local light, crowding, and overall resource limits based on metabolic rules. Trees grow and compete for local light while sharing total resources. The researchers found that tree sizes settle into two distinct mathematical patterns, called power laws. How strongly trees fight for resources versus space sets these patterns. Seeds arriving and local resources decide where one pattern shifts into the other. Finally, disturbances at a forest edge disrupt species balance and spread deep inside, far past how far a single plant drops seeds.
Imagine a crowded concert where people are trying to get closer to the stage. Those near the front have the best view, but they are packed tightly. Those far back have more space but a worse view. Now suppose the band occasionally throws t-shirts into the crowd, and people can catch them and move forward. The distribution of people from front to back depends on how many t-shirts are thrown and how tightly people pack. In this paper, trees are like people, light is the view, and seeds are the t-shirts. The model predicts two distinct patterns of tree sizes, depending on whether competition for light or for space dominates.
This theory gives ecologists a concrete way to predict how forests respond to disturbances like edge effects or fragmentation. It shows that a small disturbance at the boundary can ripple far into the forest, changing the balance between species. That matters for conservation planning and for understanding how forests store carbon.
The model is minimal and may not capture all real-world complexities like species interactions or climate effects. The results are analytical and have not been tested with empirical data. The propagation of boundary disturbances is shown theoretically but not observed in real forests.
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A multiscale theory based on metabolic scaling connects forest dynamics to tree-size distributions — Christian Grilletta, Tommaso Anfodillo, Gaia Pasqualotto et al.
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.