Application of the Gumbel CDF or Weibull CDF to forest stands may be useful for describing extreme values of maximum or minimum diameters at different working scales (stand, forest, region). These extreme values are not usually of great interest in most practical cases; for example, timber products are often classified for different industrial uses after felling. However, maximumdiameters are important in relation to the choice of harvesting machines used, and harvesting and felling may be limited by the size of machine heads.