A method for describing plant architecture which integrates topology and geometry

This paper presents a method for describing plant architecture using topolo gical and geometric information. This method is based on the use of a multi scale model of plant topology-called multiscale tree graphs-which is extend ed to include geometry. The relationships between both multiscale topology and geometry are explicitly identified and topology and geometry are shown to contain redundant information. This redundancy is expressed as sets of c onstraints between the geometrical parameters of plant components that belo ng either to one scale or to different scales. These within- and between-sc ale constraints are used to reduce the number of measurements when digitizi ng plant architecture and to implement the geometrical parameters that are not specified. Different solutions for simplifying plant architectural desc riptions are proposed. The method, implemented in software dedicated to pla nt architecture analysis (AMAPmod), does not depend on the plant species or on the geometric model used to describe the plant components. The multisca le approach allows plant architecture to be represented at different levels of accuracy. This method is illustrated on two plants, a 3-year-old apple tree and a 20-year-old walnut tree, which correspond to applications of dif ferent sizes and with different goals for the representation. (C) 1999 Anna ls of Botany Company.