Biomass and carbon data from blue oaks in a California oak savanna

Stem circumference at breast height (1.4 m above ground), tree height, distance from the ground to the base of the crown, and crown radii from the stem to the average drip line were measured for fourteen blue oak (Quercus douglasii) trees from a California site. The trees were felled, and we determined mass of stems, branches, twigs, and foliage; and analyzed carbon and nitrogen in branch and stem (0.44% N, 45.85% C) and leaf (2.13% N, 45.11% C) samples. Equations estimating biomass from diameter at breast height (dbh) or diameter at root collar (drc) were developed through regression. We applied our equations to blue oak data from the U.S. Department of Agriculture, Forest Service, Forest Inventory and Analysis Program (FIA) database. Our biomass and carbon estimates were generally comparable to but exceeded FIA's predictions by about 15% and 7%, respectively.