2 min read

How the Renewable Fuel Standards Limit Potential Wood Supply

Although the RFS was intended to increase the use of renewable fuels, the legislation restricts qualified feedstock at the same time it mandates biofuels. To be considered RFS compliant, producers must use qualified materials from qualified sources according to four criteria:

  1. Ownership: Wood biomass that originates on land owned by the federal government is ineligible.
  2. Origin: Planted trees, tree residue, slash, and pre-commercial thinnings that comes from tree plantations is eligible. On non-plantation land, only slash and pre-commercial thinnings qualify.
  3. Conversion: Tree plantations must have been cleared prior to and actively managed no later than December 19, 2007.
  4. Non-ecologically sensitive: Biomass sourced from ecologically sensitive or old growth forests is excluded.

In this blog post, we take a look at what the EPA considers planted trees, tree residue, slash, and pre-commercial thinnings.

Planted Trees

The EPA defines planted trees as “trees harvested from a tree plantation.” A tree plantation consists primarily of hand-planted or machine-planted trees.  Trees originating from natural seeding by the mature trees growing on plantation land also qualify as renewable biomass. Therefore, “planted trees” is a misnomer in the sense naturally-regenerated trees on plantation land is allowable under the RFS program.

Tree Residue

The wood residue generated when planted trees that are harvested from actively managed tree plantations and processed for use in another application such as lumber, paper, or furniture is what the EPA considers tree residue. Qualified wood raw materials maintain their status as renewable fuel feedstock when processed for use in the manufacture of wood products.

Producers may generate RINs only for the biogenic portion of the tree residues. Tree residues mixed with chemicals or other materials during production are not eligible. Likewise, residues lose their qualified status if mixed with tree residues that did not originate on an eligible tree plantation.


The EPA considers slash as the material typically left on the forest floor following a logging operation or after a disturbance such as a storm or fire. Furthermore, materials traditionally left on the forest floor to replace nutrients in and improve the quality of soil qualify as slash. This includes tree tops, branches, bark, and unmerchantable trees.

Pre-Commercial Thinnings

Trees removed to promote the growth and improve the quality of the most desirable trees in a stand are considered pre-commercial thinnings. The EPA does not limit trees harvested as part of a pre-commercial thinning in terms of diameter, citing tree diameter varies according to the type and location of forest.

Trees that remain in a stand after a first pre-commercial thinning are restricted as qualified biomass. The EPA takes the position that trees that remain after the first thinning cannot generally be considered pre-commercial thinnings at a later date.

However, in the US South, it is common practice to thin stands twice between the time they are planted and the final harvest. Under the terms of the RFS, only those trees removed in the first thinning would qualify as renewable biomass.

This caveat could have implications in regards to the timing of thinnings, although it is most likely that timberland owners will continue to manage their timber assets to maximize sawtimber production as the economics are more favorable than they are for biomass. Any adjustments made in timing to accommodate biofuels markets will be made within the boundaries of this higher objective. 

This information and more is available in our latest whitepaper. Click the banner below to download.

Definitions from the Environmental Protection Agency 40 CFR Part 80 Regulation of Fuels and Fuel Additives: Changes to Renewable Fuel Standard Program; Final Rule. March 26, 2010.