New methods of spatial simulation of forest structures and their implications for updating forest inventories

This paper presents a heuristic approach to combining inventory data with a distance dependent individual tree model. For this purpose a special inven tory data interface called ISIS was developed, which enables inventory upda ting for circle, concentric circular and angle count sampling. The methods of this approach are based on the structure generator STRUGEN (PRETZSCH, 19 93), which uses information on stand structures of the Bavaria-wide network of long-term experimental plots aggregated in parametric functions. In add ition the new methods derive spatial information from inventory data, in or der to adjust the simulated stand structures to the original ones of a cert ain region. The algorithmic sequence of the spatial reproduction is decribe d in the figures 2 and 3. The methods of the inventory data interface are v alidated. The results of the validation (see tables 1-3) show that it is se nsible to increase the quality of reproduction by using consistently spatia l information, which the sample contains.