Visual grading of standing trees: first trials on Norway spruce from Trentino region

Abstract

The grading of standing trees is subjective and often different operators of the wood chain make different evaluations. The paper examines the possibility to objectively grade standing Norway spruces from the commercial point of view, by the observation of some dendrometric, qualitative and morphological parameters. So this scope has been derived a method from the prEN 175.4503, proposed and abandoned by the CEN TC 175. We tried the method on 64 standing Norway spruces from 8 different stands in Trentino Region. Selected and graded trees were cut and sawn, and from the commercial evaluation of obtained boards a quality index has been calculated. That index was compared to the grades of standing trees. Results allow a positive evaluation of the grading method, nevertheless some changes and new parameters to be considered, seem to be necessary.