Exploring plant topological structure with the AMAPmod software: an outline

A method for the measurement of the three-dimensional (3D) architecture of trees was applied to describe two 2O-year-old walnut trees, one of them is a timber tree while the other is a fruit tree. The method works at the shoot level and simultaneously describes the plant topology, the plant geometry and the shoot morphology. The method uses a 3D digitiser (3SPACE@ FASTRAK@, Polhemus Inc.) associated with software DiplAmi designqd for digitiser control and data acquisition management. Plant images may be reconstrxcted from the data set by using the ray tracing software FOV-Ray. Visual comparison between photographs of the walnut trees and images synthesised from digitising was satisfactory. Distribution of basal shoot diameter, as well as leaf area and fruit distributions for both the timber and the fruit tree were non-unifomly distributed in the crown volume. Gradients were likely to be related to the light distribution within the tree. This is in agreement with previous experimental results on several tree species, and also with the predictions of tree architecture models based on lightvegetation interactions.