Three gradients in the architecture of trees

Abstract

An earlier paper by the same author set out a symbolic notation for tree architecture designed to codify the Halle-Oldeman tree models. This was used to construct a number of rules of tree architecture with the aim of discovering the limits of tree architectures. The present paper continues this search with six more rules. Applying the rules reveals eight new models or extensions of existing models which probably do not exist. Ten of the rules are combined to suggest three gradients, directions in which differences between trunk and branch axes can occur. There are gradients in in determinacy and tropy of trunk and branch axes and in the modes by which trunk axes relay, branch axes are attached and branch axes relay.