Klassifikation und Vermessung von Rissen in Nadelrund- und Nadelschnittholz

Abstract

Classification and measurement of visible cracks in softwood logs and sawn timber Cracks as an attribute of logs are an important quality factor for the production of sawn timber. They can develop in the standing tree due to growth stresses or external influences, but also in felled trees due to tension releases or drying. The definitions for different types of cracks that can be found in standards and in literature lack consistancy and are not sufficient for scientific use. This paper proposes a classification scheme for cracks in logs and sawn timber that is based on existing definitions in literature but also includes newly drafted definitions. A method for the estimation of crack damaged volume in wood is presented, which is based on manual measurement of the crack features for scientific use. The results give detailed and, depending on the dimensions of the sawn timber, also precise information about type, size and position of cracks as well as the expected volume of reject.