Grape canopy structure, light microclimate and photosynthesis. <p>1. A two-dimensional model of the spatial distribution of surface area densities and leaf ages in two canopy systems</p>

Abstract

The development of a model of the vertical and horizontal distribution of leaf, shoot, and fruit surface area densities, SAD (surface area per unit of canopy volume, m² · m^-3), as well as leaf types (main and lateral leaves) and leaf ages is described for two canopy systems (Espalier-type, S-System, and 3-wire Cordon, C-System). Leaf, shoot and fruit SAD increased towards the canopy interior for both systems and reached maximum values of 12, 0.8, and 1.2 m² · m^-3, respectively, for the S-System, and 10, 0.4, and 1.0 m² · m^-3 for the C-System. The fruit zone was always located near canopy areas of highest density. The distribution of surfaces of leaves of different ages from primary and secondary shoots was distinctly different for the two canopy types tested.