Relative carbon sequestration of forests is of increasing interest in the face of climate change. Older forests with larger, heavier trees are thought to store more carbon than younger forests. The aboveground carbon storage of two oak-hickory forests of different ages (based on 1940 aerial photographs) was compared to test this assumption. Diameter at breast height (dbh) was measured for trees greater than 10 cm dbh along several transects in both forests, and was used to calculate mass of carbon stored in each tree based on species-specific allometric equations. While the average carbon stored per tree in the older forest was about 42% greater than that of the younger forest, the average carbon stored per square meter was about 36% greater for the younger forest than the older one. These results have implications for the justification and management, especially of urban forests patches, with respect to their ecosystem service of carbon sequestration.