METHODS OF STRENGTH GRADING OF STRUCTURAL TIMBER – COMPARATIVE ANALYSIS OF VISUAL AND MACHINE GRADING ON THE EXAMPLE OF SCOTS PINE TIMBER FROM FOUR NATURAL FOREST REGIONS OF POLAND

Abstract

The article covers the strength grading system methodology for construction timber. The presented analysis identified important issues concerning the verification of structural and geometric characteristics during construction timber strength grading by visual and machine method. The following considerations specified the guidelines for the classification of coniferous construction timber in sawmills. The paper also presents the results of the visual and machine classification performed for Scots pine timber from four natural forest regions of Poland. As a result of the conducted research it was stated that the use of machine classification equipment allows obtaining a larger amount of pine timber with better mechanical properties and eliminating the rejected timber.