01The gap in the current RFS definition
The RFS defines which raw materials count as “renewable biomass” under Section 211(o)(1)(I) of the Clean Air Act. Only fuels produced from qualifying feedstocks generate Renewable Identification Numbers (RINs) which are the compliance credits that producers get paid for.
Under the current definition, much of the woody material removed during forest thinning and wildfire prevention does not qualify. Pre-commercial thinnings, storm debris, slash, and brush cleared from defensible space around structures all fall outside the RFS's biomass eligibility criteria, despite already being removed from forests and wildlands as part of routine land management.
Without the RFS-linked financial incentive to convert it into renewable fuel, it is typically burned in open-air piles, left to decompose or hauled to landfills. All three outcomes release carbon. None generate RINs.
02What the Wildfire Reduction Market Expansion Act changes
Proposed on July 22nd 2026, the bill would amend Section 211(o)(1)(I) of the Clean Air Act to broaden what qualifies as renewable biomass under the RFS.
Expanded forest products manufacturing materials
The bill adds several material types to the list of eligible biomass from forest products manufacturing:
- Wood residuals
- Paper residuals
- Sawdust, wood chips, and shavings
- Bark and sander dust
- Paper recycling residuals
These materials were previously excluded despite being generated as byproducts of commercial forestry operations.
New eligible land categories
The bill opens three new categories of land from which woody biomass can be sourced for RFS-qualifying fuel production.
Biomass from private land qualifies if it is enrolled in a forest sustainability certification program, classified as timberland for tax purposes, or if the landowner certifies it is managed for long-term timber production.
Material from fuel reduction treatments and ecological restoration on federal land becomes eligible, as long as it is not suitable for use as sawlogs and the sourcing complies with the applicable forest management plan. The plan does not need to mention renewable fuel production as an intended use.
Land owned by an Indian tribe or held in trust is also included.
Defensible space and wildland-urban interface materials
Vegetation removed as part of defensible space clearing around structures (and material from wildfire risk reduction activities in the wildland-urban interface) also becomes eligible under the amended definition.
03Why it matters for renewable fuel producers
The most direct impact is on cellulosic ethanol and SAF producers. The bill opens up forest thinning material and wildfire prevention residues as eligible feedstock for transportation fuel, including aviation fuel. For producers who have been constrained by feedstock availability, this is a significant expansion of what they can work with.
A UC Davis study found that every dollar invested in forest fuel reduction treatments saves roughly $3.75 in wildfire suppression and damage costs. By creating a market for this material through the RFS, the bill gives wildfire prevention a brand new revenue stream.
04New compliance and documentation requirements
New feedstock categories come with new compliance obligations. Producers sourcing woody biomass under the amended definition will need to:
- Maintain certification letters from landowners or federal field offices
- Verify that federal land material is not suitable for use as sawlogs
- Confirm that sourcing complies with the applicable forest management plan
- Document the full chain of custody from origin to fuel production
For organisations already managing feedstock documentation across LCFS, RFS, or ISCC, this adds another layer. For those still relying on spreadsheets and email chains, it may be worth considering whether existing systems can handle the additional documentation load.
