Résumé
Oak (Quercus robur and Q. petraea) is the most important species in French forestry. This wood is purchased by a great variety of firms, with prices that can range on a scale from 1 to 100. The main determinant of wood use is its quality and this depends on the presence or absence of defects in the wood. There is a great diversity of defects, but their importance for estimation of wood quality is not well-known. We have formulated a methodology for measuring the severity of defects in the final use of the wood. The measurement is based on two complementary indicators. The first one evaluated the drop in price caused by the presence of defects on individual logs sold during German sales of felled logs. As prices are linked not only to the severity of defects and as we did not come across a complete range of users or defects during this sale, a second indicator was constructed to complement the first one. This second indicator was based on a survey in which people were asked to sort virtual logs in order of preference. This methodology is useful for an initial approach to the problem but some improvements are needed to provide complete answers