INFLUENCE OF CROWN STRUCTURAL-PROPERTIES ON PAR ABSORPTION, PHOTOSYNTHESIS, AND TRANSPIRATION IN SITKA SPRUCE - APPLICATION OF A MODEL (MAESTRO)

The structure of a tree crown can be described by the spatial distribution, inclination, and orientation of all the phytoelements (leaves, twigs, branches, trunk, etc.), and their geometric properties. The following four structural properties have been studied in relation to radiation absorption, photosynthesis, and transpiration using a simulation model named MAESTRO: crown shape, total area of leaves and their spatial distribution within the tree crown, and the leaf inclination angle distribution. It was found that the total area of leaves and their spatial distribution within the tree crown are far more important than the other two properties for radiation absorption, photosynthesis, and transpiration.