When the observed mode value was used to fit the Gumbel distribution, the best results were obtained for the minimum diameters of B. pubescens and P. radiata stands. However, poor results were obtained in the other cases, indicating that this fit is not a viable alternative for modelling maximum diameters. For Q. robur stands, the Gumbel and the Weibull distributions fitted by the moments approach yielded equally good results. Finally, the Gumbel distribution fitted by the observed mode method or by the estimated mode method (moments) is more suitable than the Weibull distribution for modelling minimum diameters in P. pinaster and P.