EVALUATION OF INVENTORIES BASED ON SAMPLE PLOTS OF VARIABLE SIZE

This paper deals with the estimation of per hectare values in forest i nventories, based on sample plots of variable size. They are used in a national monitoring system in Slovakia and also, in a more complex fo rm, as concentric circles in regional inventories and inventories of f orest enterprises in Germany. A comprehensive theoretical analysis is completed by a simulation study in an artificial forest model in order to illustrate the results. In case of systematic samples on a lattice , as it is typical in forest inventory practice, the mean of the per h ectare values of sample plots is shown to be a suitable estimator even if variable plot sizes are used. Instead, the ratio estimator can hav e a remarkable bias.