ASTM International cleared Fischer–Tropsch synthetic paraffinic kerosene (FT-SPK) for jet use in 2009, but no pyrolysis-derived SAF has yet qualified under ASTM D7566.

Sustainable aviation fuel output rests almost entirely on the hydroprocessed esters and fatty acids (HEFA) pathway, which draws on vegetable oils, animal fats and used cooking oil. That limited feedstock pool constrains long-term SAF production growth and has put woody biomass on the agenda of project developers, airlines and feedstock analysts.

Why woody biomass is moving onto the agenda

The candidate material covers forestry residues, sawmill and other wood-processing byproducts, and low-value fiber unsuitable for higher-value markets. Aggregate biomass estimates may not represent the volumes commercially accessible to SAF producers, because availability depends on regional forest conditions, competing demand, collection and transport costs, and the ability to secure supply over a project's life.

Pulp and paper, wood pellet and bioenergy operators already draw on the same fiber, shaping what a new SAF plant can actually procure at a workable price.

How do the two thermochemical pathways compare?

Two routes dominate the woody-biomass-to-jet conversation: gasification combined with Fischer–Tropsch synthesis, and pyrolysis-to-jet. Both accept similar solid feedstocks, but their commercial and regulatory maturity differs sharply.

Gasification-FT has the clearer near-term route to market. The process converts biomass into syngas, which FT synthesis rebuilds into hydrocarbons for upgrading, with feedstock preprocessing, gasification, FT and upgrading typically co-located at a single integrated site. The 2009 Annex A1 approval established production and fuel-quality requirements independent of the syngas source, opening the door for woody-biomass-derived FT-SPK. Capital intensity, feedstock logistics and consistent high plant utilization remain the principal commercial risks.

Pyrolysis-to-jet heats biomass in a low-oxygen environment to produce bio-oil, char and gas before upgrading into SAF. The pathway has not yet qualified under ASTM D7566, and the oxygen-rich, acidic and unstable bio-oil requires specialized handling and extensive hydrogen-based processing. Fuel qualification, processing complexity and the marketable SAF yield per unit of bio-oil are the principal risks.

Does the US South have enough fiber?

Most early woody-biomass SAF projects are clustering in the US South, where timber inventories and sawmill infrastructure are concentrated. Homebuilding and repair and remodeling account for about 70% of softwood lumber demand, supporting sawlog harvests and sawmill output and, by extension, the residues that could feed a SAF plant.

The same fiber base supplies pulp and paper mills, bioenergy facilities and wood pellet producers, so localized competition can pressure prices. Fastmarkets does not see that as a regional shortage signal: across the US South, timber inventory continues to expand because forest growth exceeds harvest, a trend the analyst expects to continue across its 15-year forecast. Declining pulp demand and rising sawmill output could improve feedstock availability for SAF over the next five years. Pulp mill closures, however, may weaken harvesting activity, transportation networks and processing infrastructure, lifting supply-chain risk.

What separates a viable project from a speculative one?

Three variables will matter most: ASTM qualification status, regional biomass availability within a workable procurement radius, and delivered-cost exposure once incumbent fiber buyers are accounted for. Fastmarkets couples pathway readiness and regulatory milestones with timber-supply data to screen opportunities against those variables.

Whether woody biomass ultimately broadens SAF production beyond HEFA will hinge on whether conversion technologies and supply chains operate reliably at commercial scale, and whether project economics hold once forest-products incumbents, mill closures and procurement logistics are priced in.