A dominant-tree thinning was conducted in 2003 in a 69-year-old even-aged northern hardwood stand, clearcut in about 1935, where a precommercial thinning study had been conducted in 1959. The 2003 commercial thinning concentrated on the removal of the early maturing, short-lived paper birch and aspen, the largest-diameter trees in the stand (hence the term "dominant-tree thinning"). Diameter growth rates after thinning, up to about 6 years per inch over the following 12 years, were acceptable although not greatly different from the unthinned plots. Basal area growth response was highly acceptable after thinning: about 2.3 ft2 per acre per year. Annual basal area growth was about negative 0.9 ft2 per acre on the unthinned plots. Understory development of beech and shrub species was dense under the thinned plots, and will require treatment/removal during the regeneration phase.