LE13207
- Leonardo da Vinci observed in his notebooks that "all the branches of a tree at every stage of its height when put together are equal in thickness to the trunk." There have been surprisingly few assessments of this rule, but the available data indicate that the Leonardo rule holds for a large number of species. Despite this scarcity of experimental evidence, it is safe to state that Leonardo's rule has not been disproved. As a matter of fact, it is so natural to the eye that it is routinely used in computer-generated trees. In this Letter, it is proposed that this rule is a consequence of the tree skeleton having a self-similar structure and the branch diameters being adjusted to resist wind-induced loads.
