In contrast to SRWC biomass, woody biomass from stand thinning is obtained from inter­mediate treatments in forest stands managed for sawlog or pulp production, or managed for non-market values like recreation and wildlife habitat that may be enhanced or protected by thinning treatments. In forestry, thinning operations are partitioned into pre-commercial and commercial thinning. Pre-commercial thinning incurs a cost, typically requiring invest­ment of $100-150/acre ($247-371/ha), but generally results in better growth and higher production for the stand over the rotation. In addition, pre-commercial thinning is often used to reduce fire risk or manage insects and disease, regardless of impacts on long-term commercial output. Commercial thinning treatments are deployed in even-aged silvicultural systems, when feasible, 10-20 years before a terminal harvest. At this point in stand growth, stems are large enough to yield at least one small diameter sawlog, and revenue from the sale of merchantable sawtimber outweighs the logging costs associated with operations. At some critical threshold price, or under certain financial incentives, markets for woody biomass may help to further offset logging costs and help to make commercial thinning financially viable in stands where it otherwise might not be through supplemental revenue.

A number of supply chain pathways have been explored for thinning materials to be used for biofuels or bioenergy that are low in both ash and moisture content. In southern pine plantations, thinned stems are typically harvested with wheeled feller-bunchers that are able to proceed through plantation rows in alternating fashion, removing a stem from the left, then one from the right, and so forth. Pre-bunched stems may then be collected by a grapple skidder or forwarder. Or, in order to reduce the moisture content of stems for subsequent processing, pre-bunched stems may undergo in-woods drying before being removed for processing. Efforts to reduce the ash content of woody materials from thinning operations have evaluated extraction methods that fully support stems using forwarders or wheeled loaders, minimizing dragging and resulting soil contamination associated with grapple skidding.

In the western United States, a major potential source of biomass is thinning materials removed from fuel treatment operations on national forests. Frequently these types of treatments result in net costs, with relatively low value material removed from treatment units. Recent analysis of U. S. national Forest Inventory and Analysis data [3] using the BioSum model has shown that fuel treatment costs in the western United States range from very moderate (e. g., $100/acre) to infeasible (>$10 000/acre) on the landscape, depending on logging system used, topography, and transportation distance to utilization facilities. Remote stands on steep slopes that require cable logging or specialized equipment for treatment tend to be prohibitively expensive to treat.