Experience in deciphering the Betula pubescens resistograms for the detection of trunk rot in woody plants

The wood diagnostics and quality control method based on measuring the material's resistance to drilling is one of the fastest growing areas of wood science and expertise in timber construction. The purpose of the study was to determine the minimum number of drills required to diagnose the internal condition of a growing tree's trunk and to identify patterns of wood pathology distribution in the north-south and west-east directions, as well as along the height of the tree to assess the possible location of the break. This article presents the results of processing the drilling profiles of a model birch (Betula pubescens) and experimentally calculated wood density obtained with the Resistograph® device. The uneven distribution of trunk rot both along the height of the trunk and along the drilling directions north-south, west-east was found. This means that for a reliable diagnosis of the internal condition of the wood it is necessary to drill along the length/height in at least two mutually perpendicular directions in the selected cross-section, at a maximum pitch of 1 m. A histogram of the length/height condition of the wood, based on the decoded resistograms, gives a clear indication of the possible location of the break.