BRANCH GEOMETRY IN CORNUS-KOUSA (CORNACEAE) - COMPUTER-SIMULATIONS

Computer simulations similar to actual trees were constructed using si mple branching rules. Branch orientation with respect to the direction of gravity was a fundamental consideration. In Cornus kousa BUERG. ex HANCE, several types of branches develop from winter buds, varying fr om orthotropic shoots to plagiotropic ones. Based on actual observatio ns and measurements of branching structures with a wide range of orien tations, we made a flexible geometrical model consisting of five forki ng branches that varied in outgrowth depending on the direction of the shoot with respect to gravity. Repetition of the branching by compute r generated a realistic tree pattern, which was close to the shape of a young C. kousa tree. Reproductive shoots seem to be under a branchin g rule that was a modification of vegetative branching, although the r eproductive branch size was considerably smaller than the vegetative o ne, and reproductive branching was bifurcated instead of five-forked. We conclude that all branchings in orthotropic and plagiotropic shoots in the vegetative phase and shoots in the reproductive phase are form ed under the same branching rule, but each has different parameter val ues.