Economic comparison of woody biomass harvesting strategies in United States
He, L., B. C. English, D. Ugarte, and D. G. Hodges.  2014.  Journal of Forest Economics, 20:174-191.

Abstract:
The production reliability and relatively low costs of sustainably harvested woody biomass such as logging residue and low value roundwood could make it a significant component of the Renewable Fuel Standards portfolio. This research explored a set of woody biomass harvesting combinations of different sources and wood types using a cost minimizing linear programming model populated with disaggregated regional inventory, yield, and cost data, and projected future conventional wood demand of the United States. The model pre-satisfied conventional wood demand before harvesting roundwood as woody biomass. Findings suggest that collecting forest residue and non-merchantable (small sized) timber may provide the largest initial contribution in woody biomass supply. Regional estimations imply that not all regions have the capacity to develop bioenergy plants without using merchantable (medium sized) wood. Within a reasonable range of harvesting costs, demand for roundwood is expected to increase with higher energy production targets. Harvesting merchantable natural softwood as woody biomass has a relatively small impact on marginal supply costs. This will result in little or no disturbance to merchantable natural softwood timber management and operations if demand for woody biomass increased.