Estimating Biomass Availability and Cost when Implementing Forest Restoration with Tethered Harvest Systems

Using an adaptation of Forest Inventory and Analysis’s BioSum framework, which models prospective management of forested landscapes using forest inventory data, we tested several fire-resistance-promoting restoration treatments, implemented with tethered cut-to-length harvest systems, for effectiveness and economic feasibility in the dry national forests of southern Oregon and northern California. Treatments elevated fire resistance on most forested area, primarily via increases in the separation of canopy and surface fuels and among tree crowns, and the most effective treatments could more than cover treatment cost with sales of wood in most stands. If, instead of disposal by burning at the landing, small-diameter wood was delivered to a biochar facility capable of paying US$50 per bone dry ton, this would increase the share of forest area on which treatment could break even from 61 percent to 67 percent, slightly more than the 66 achievable with a treatment subsidy of US$100 ac⁻¹. Potential treatment area appears to be currently constrained by institutional capacity, not treatment effectiveness, economics, opportunity, or need. Even with the currently modest scale of management activity, sufficient biochar feedstock is available in the upper Klamath Basin to supply at least one large-scale biochar facility over the next 20 years.