Much information is available for specific gravity and other properties of wood and bark, but it is widely scattered in the literature. This paper compiles information for estimation of biomass for 156 tree species found in North America for use in national forest inventory applications. We present specific gravities based on average green volume as well as 12 percent moisture content volume for calculation of oven-dry biomass. Additional information is included on bark thickness, bark voids, and bark percentages by species and green and dry weight of wood and bark. --