Abstract Forests in the eastern and northwestern United States often develop in even-aged patterns, with certain species predictably forming the upper canopy and others relegated to lower strata. The vertical sorting (or stratification) by species and broad ranges of diameters has sometimes led foresters and ecologists to assume these stands are all-aged. For this reason the stands have often been selectively logged and thereby degraded unintentionally. If manipulated as even-aged or in age classes, these mixtures can often be as economically and ecologically advantageous to manage as pure stands are.