Abstract The availability of wood, be it harvested for sawlogs, pulpwood, biomass, or other products, is constrained by social and biophysical factors. Knowing the difference between social and biophysical availability is important for understanding what can realistically be extracted. This study focuses on the wood located in family forests across the northern United States. Family forest owners control 54% of the 7,685 million dry tons of wood in the region. To estimate availability, we begin with the total resource and then apply constraints related to slope, drainage, site productivity, tree size, size of forest holdings, distance to roads, harvesting restrictions, population pressures, and ownership attitudes. These constraints reduce wood availability significantly, by nearly two-thirds according to our calculations. The vast majority of this reduction is due to social factors, in particular owner attitudes. The greatest state-level reductions in wood availability are in Connecticut, Delaware, Maryland, New Jersey, and Rhode Island, all of which have estimated reductions of more than 75%.