Vierzig Jahre permanente Stichprobeninventuren in der Schweiz | Forty years of permanent inventory sampling in Switzerland's forests

Abstract

Permanent sampling procedures were introduced into Swiss Forestry Management around forty years ago. Discussions arising from two of six talks (from P. Brassel and M. Zobeiry) presented at a Monday Colloquium devoted to this theme at the ETH Zurich are summarised. The successful Swiss National Forest Inventory, which has been carried out twice so far, is based on permanent earth samples, and supplemented with aerial surveys. For financial reasons, the planned third survey will only comprise one repetition of the second sampling with a few additions to the catalogue of characteristics. In the natural forests of northern Iran permanent sampling has been carried out for the past twenty years, beginning with a survey of the 1000 hectare training forest of the University of Teheran, with three surveys so far. In 1995/96 an initial survey was carried out in the 1.8 million hectares of northern Iran’s forests with a total of 3611 permanent samples. In the Monday discussion critique was voiced that, in recent years in Switzerland, practically only large-area inventories have been further developed, but not inventories of individual enterprises. These should not be neglected, not least because of the advantages of longer time horizons in the data. It is not necessarily additional information that is required for enterprises but better instruments and models with which to interpret existing data.