In the course of almost 40 years various researchers, at what used to be TNO's Forest Products Research Institute, currently the TNO Centre for Timber Research, conducted studies into the physical properties of wood. The first studies and calculations were carried out by Mr E. Prochaska, after which Mrs G.M.C. Koning-Vrolijk continued the work. Indeed Mrs Koning-Vrolijk wrote the Institute's first publication (1962), an Eng lish version of which was published in 1963 (3) on the occasion of FAO and IUFRO Conferences held in the United States. Thereafter, the Institute's work was carried on by...