A network of 145 plots that were examined prior to the December 26, 1999 storm was re-examined thereafter so as to identify and quantify the influence of dendrometric and environmental factors on the stability of even-aged high beech (Fagus sylvatica L.) forests in North East France. In addition the damage recorded was compared with another sample of 38 plots of coppices-with-standards and 40 plots of even-aged high forest located in the vicinity of Nancy subjected to very strong winds (more than 140 km/hr) on similar sites to identify the morphological features of trees and site parameters that best explain the probability of windthrows. For even-aged high forest, the susceptibility factors we identified were wind speed, stand dominant height beyond a threshold of 23.5 m, the depth and nature of obstacles to rooting, the topographic location. These factors have the expected effect and their relative impact can be quantified using a logistic model that predicts the rate of damage in terms of stem numbers. On the other hand, no significant effect on the stand was detected concerning stocking density, the slenderness ratio, or the characteristics of the latest cut (intensity and date). The behaviour of beech with respect to wind, particularly when it is not bearing leaves, is unlike that of conifers. Although damage under both systems was mostly similar, juvenile (low-lying) stands under high forest treatment appear to be less affected whereas mature high forest suffers more than coppices-with-standards. A more refined logistic model provides an explanation for individual susceptibility of trees to very strong winds. The model applies both to high forest and coppices-with-standards and makes use of soil depth and tree size (lever arm length from ground to middle of crown and width of crown). This result seems logical but is nonetheless in contradiction with what is held to be true of conifers - for a given total height, the probability of windthrow in beech increases with the diameter of the tree (highly correlated with crown diameter) and hence increases as the slenderness ratio totH/dbh decreases. The implications of these results for beech cultivation are discussed