A New Framework for Forest Inventory Optimisation: Theory, Implementation and Perspectives

Under a point sampling system with terrestrial sample plots the design-variances of the estimators depends on the spatial distribution of the tree locations in the for-est. An universal framework for forest inventory optimisation needs therefore a spatial population model. In recent research work carried out at the Swiss Federal Institute of Technology in Zürich, Switzerland, it has been shown, that a simple population model assuming a stratified Poisson distribution of the tree locations, leads to simple expressions of the anticipated variance (mean design-variance un-der the model) under a wide variety of sample designs and to intuitively under-standable optimisation rules. Some of the findings of these studies are presented and detailed examples for the optimisation of the tree selection probabilities and plot sizes are given. Fur-thermore, strategies for measuring the efficiency of sample design alternatives with respect to the most important target variables of an inventory are given, and further developments are outlined