Economic Estimation of the Available Biomass following Logging Operations in Western Oregon and Washington

A two-step method was developed to estimate the economically available biomass from forest operations in the Pacific Northwest. Step 1 measures the amount of biomass in piles from a variety of logging operations. Step 2 applies logistics models to determine the amount of biomass that is recoverable by computing the extraction costs depending on the distance from the landing. Cable units included only the biomass piles located at the landings, while ground-based units computed the collection and transport of each pile to the most cost-effective landing using geographic information system and simulation tools. This approach was applied to operations on state and private timberlands in Oregon and Washington. For the cable logging units, the average pile size was 46.7 green tonnes of residue, and this material was either on or next to the roadside landing. It produced few large piles with an average of 24.75 green tonnes per ha. For ground-based operations, approximately 54 percent of the residue in the harvest units was 90 m or less from the landing. Collection cost increases as the material is farther from the landing and ranged between about $17.6 per green tonne at distances of 15.2 m to $37 per green tonne at distances of 213 m from the landing. Depending on the distance from the landing to the bioenergy facility, it is possible to estimate how far from the landing into the forest to reach to economically collect the biomass.