In ecological, hydrological, geomorphological and biophysical process modeling, the forest canopy is generally characterized by Leaf Area Index (or LAI, the one sided total leaf area per unit ground area). However, recent research dlearly demonstrated that existing measurement techniques determine LAI of forest stands in a most unreliable way. This research intends the development of an accurate and precise quantification of the forest canopy structure, focusing on LAI. The first objective is to develop a rapid, reliable and non-destructive method for LAI measurements. The second objective is to refine the quantification of forest canopy structure by modeling the spatial distribution of leaves as a fractal problem. This stud will be based on digital hemi- sperical photography because the available instruments for measuring LAI are model-specific developed and their information content is limited to necessary model parameters.