Mature (55 +- 7 years) largetooth aspen (Populus grandidentata Michx.) were harvested from three stands in northern lower Michigan, U.S.A., using dimension analysis techniques. The three harvest sites represent the range of soil quality characteristics that influence tree growth rates in the Great Lakes Region of the central U.S.A. (i.e., good, intermediate, and poor in terms of net productivity). Stem weight increment accounted for 46.4% of all aboveground tree component production at the poor site and over 52% at the good and intermediate sites. Net annual production per unit leaf weight was about 33% less for the poor site aspen as compared with the good site aspen. Total aspen tree production at the good and intermediate site was 3.7 and 2.5 times greater than production at the poor site. Although aspens display a large difference in net productivity among the three sites and clonal groups, the wood is surprisingly uniform in density (specific gravity = 0.38 +- 0.03). Good site wood with wide rings has nearly equal wood anatomy to wood with narrow rings on the poor sites, with the difference being in the total number of cells produced. Thus, volume production in aspen is a good measure of biomass production, and good sites simply yield greater quantities of wood, of equal quality, than poor sites. A sixty-year comparison, at five-year intervals. of radial increments and bole wood production at each site indicates that good site superior clones had twice the radial growth and production of inferior clones on the good site while superior clones on the poor site had three times the growth of inferior clones at the poor site. The selection of superior aspen clones for stand regeneration could significantly increase productivity on all sites.