This data set contains the measurement of diameter at breast height (1.4 meters above ground) (dbh) for individual non-oak and oak trees at the Future of Oak Forests (FOF) experiment in Black Rock Forest (Cornwall, NY) during July and August of 2007. The North Slope site contains 12 square-shaped plots, each of 75 meters by 75 meters. Each plot was subdivided into nine equal-sized subplots, each of 25 meters by 25 meters. Within each center subplot of a plot, all individual non-oak trees with dbh of at least 2.4 centimeters were measured using metric DBH tapes (e.g. Lufkin executive thinline). This data can be used to study the individual variation and metabolic scaling of non-oak species in the Forest. All individual oak trees dbh was measured within all subplot.