Case Update: The 21-inch Rule is (probably) back

The 21-inch rule will likely become the law of the land again in National Forests east of the Cascades in Oregon.

 Photo submitted by Pam Hardy

Contributed by: Pam Hardy, Senior Attorney with the Western Environmental Law Center, and on the Steering Committee of the Deschutes Collaborative Forest Project.

A magistrate judge’s recent Findings and Recommendations (document 1 below) suggest the 21-inch rule will likely become the law of the land in National Forests east of the Cascades in Oregon once again.

Restoring local forests to be more resilient to wildfire is important to community safety, wildlife, and the outdoor recreation in Bend.  Restoration often involves thinning, but which trees should be removed is hotly debated.  There is wide-spread agreement that the largest trees, and some species, are more resilient to wildfire than others, but disagreement on many other aspects.  The recent finding is the latest exchange in the long running debate.

The “21-Inch Rule” was the most well-known element of a collection of standards and guidelines known together as the “Eastside Screens” (document 2 below). It prohibited removal of most trees greater than 21 inches in National Forests east of the Cascades, including the Deschutes. In place since 1995, the Forest Service tried to update the rule in 2021 arguing that new research had provided better ways to “adapt forest conditions to current disturbance regimes (fire), and climate induced changes including longer fire seasons.”  In 2022 six environmental groups challenged the update in federal court. 

On August 31, 2023, Magistrate Judge Andrew Hallman issued Findings and Recommendations in favor of the environmental groups.  This report is from a magistrate judge, meaning that this document includes “findings” and a “recommendation” to Judge Ann Aiken, the federal district court judge assigned to decide the case.  The decision isn’t final until she formally adopts the findings and recommendations or writes a decision of her own. 

At the center of the controversy in the case was a standard known as “the 21-inch rule.”  A “standard” is a hard-and-fast rule that allows very little latitude for change.  In January 2021 the Forest Service amended this clear standard with a “guideline,” which is more flexible.  Like the old standard, the purpose of the new guideline is to “maintain and increase old and late structure forest.”  However, the new guideline added an element which was to “favor fire tolerant species where appropriate.”  

Accordingly, the new guideline states that managers “should retain and generally emphasize recruitment of old and large trees.”  It also keeps the 21-inch rule for all species except grand and white fir, which are generally thought to be less drought and fire tolerant.  For those two fire-intolerant species, it lifted the diameter limit to 30 inches.  However, because it changed the rule from a standard to a guideline, it also said that if managers believed they could better achieve the purpose of the guideline – maintain and increase old and late structure forest and favor fire tolerant species – using a different method, that would be allowed too.

It was this flexibility, along with the vast acreage to which the rule applies, that the Magistrate Judge found created sufficient uncertainty that a more thorough analysis would be required, specifically an Environmental Impact Statement (EIS).

The Magistrate also found that the Forest Service erred by assuming, without analysis, that the amendment wouldn’t impact fish, and in failing to provide the normally required objection period.

Notably, the Magistrate found in favor of the Forest Service on the question of science.  Plaintiffs submitted four articles that they claimed demonstrated that the scientific foundation for the amendment was uncertain.  The Magistrate addressed each, and found that “The [Forest] Service has effectively addressed the limited scientific support presented by Plaintiffs and explained why the [four] articles cited by Plaintiffs do not create a significant dispute over this Project’s effects.”  He then compared those four to the hundreds of articles cited by the Forest Service in support of their amendment, and found that there “there is not a substantial scientific dispute about the historical conditions of the eastside forests or the fact that hard diameter limits can constrain managers’ ability to achieve desired species outcomes and protect eastside forests from changing fire regimes.”

The Magistrate recommended “vacating” the amendment, meaning that if the Forest Service would like to try again, they would be required to start from the beginning, and probably use an Environmental Impact Statement.

Before the final decision, the Forest Service will have an opportunity to file objections to the Findings and Recommendations.  Then, plaintiffs will be allowed to respond in writing.  Then Judge Aiken will officially decide.  At that point, the losing party can appeal to the Ninth Circuit.

NOTE: The DCFP does not currently have a consensus about the merits of the litigation, but points out that its Zones of Agreement ( ) have long concurred with the purpose of the Eastside Screens.  Our Charter and Zones of Agreement emphasize the restoration of the Deschutes National Forest to historic conditions which had many more large and old trees which were able to easily withstand substantially more fire than most trees today.

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(c) 2023 Deschutes Collaborative Forest Project