A MODEL FOR THE CANOPY STRUCTURE AND THE SPATIAL-DISTRIBUTION OF NEEDLE SURFACE IN A NORWAY SPRUCE STAND

For a determination of the canopy structure and spatial distribution o f needle surface in a Norway spruce stand a computer model of Norway s pruce was used. A short description of model input and output is follo wed by an application to a number of curled sample trees and the compa rison between experimental measurements and calculated data (Fig. 1,2) . From this information 5 characteristic trees could be constructed an d composed to a model for a 40 m x 40 m sized part of the stand (Fig. 3a to c). For the description of needle surface distribution the space , which is taken from the sample stand, was devided into cells defined by an equally sized space grid with 0.5 m resolution. All shoots with in a cell are collected by the sum of their needle surfaces and the lo cation of the cell. For graphic presentation of this data the local le af area index was calculated (Fig. 4).