Brad Seaberg mentioned the North Yuba Forest Resiliency Project in a comment. The NEPA is an EIS linked to specific RODs. Shout out to them for their NEPA experimentation (2023 ROD), for their work with partners, and for their rapid reply to my questions. There has been no litigation.
My questions are in bold and District Ranger Tom Parrack’s answers in italics.
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Here’s some of the rationale for thinning some large trees:
A century of excluding fire’s ecological role in this Landscape has resulted in high stand densities and continuous tree canopy cover in areas that would have not historically supported these densities.
The historic role of fire as a frequent, widely occurring ecological process has been largely absent. The lack of fire, combined with human activities and management, has led to alterations in forest structure and species composition. Tree densities are higher compared to historic conditions and overall tree species composition has shifted to more shade tolerant, less fire-resilient species (Knapp et al. 2013, Safford and Stevens 2017, Stephens et al. 2018).
Generally, the number of large trees (greater than 24 inches dbh) have declined by at least 50% in the Sierra Nevada ecoregion (see Figure 1 from McIntyre et al 2015, see also Dolanc et al 2014, Stephens et al. 2018, Easterday et al. 2018). Broadly, this has led to forest management goals that prioritize retention of large trees, restricting removal of all trees greater than or equal to 30 inches dbh. However, species composition has also shifted toward shade tolerant trees, which in some stands may dominate the growing space. In these types of stands, the targeted removal of some larger shade tolerant trees can provide growing space for the shade intolerant pines, recruiting the large diameter pines of the future. Moreover, trees greater than 30 inches dbh in the dripline of even larger pine trees may pose a fire hazard to the larger trees, and their removal may bolster the potential to maintain the desired larger pines on the landscape. Finally, the ability to create heterogeneous stands with openings is challenging with strict diameter limits. Collectively, this suggests that treatment needs may be more complex than the application of a strict diameter limit allows for yet given the importance of large trees on the landscape, the proposal includes stand-level field verification, documentation and disclosure, and formal public comment opportunity prior to implementing this
plan amendment. Currently, a lack of forest diversity/heterogeneity; limited seral-stage variation; and deficiencies in very large, old trees are compromising California spotted owl habitat resiliency (Forest Service 2019). A summary of references of natural range of variability (NRV) conditions for yellow-pine and mixed-conifer forests across the Sierra Nevada can be found in PSW-GTR-256 (Safford and Stevens 2017, pages 177 to 181; table 11, pages 178 and 179). Promoting development of existing large trees into very large trees and retaining existing very large or old trees aligns with the purpose and need for this proposal.
Below is what I could find in the FEIS about 30-39 inch trees. Note that the purpose and need involved both thinning, and making 1-3 acre openings.
Treatment Units with Removal of Some Shade Tolerant Conifers between 30 and 39.9 inches
My decision includes application of TERR-NORTH YUBA-STD-01 to remove shade-tolerant conifers between 30 and 39.9 inches dbh, consistent with this standard and all other applicable Forest Plan standards and guidelines, including modified SNFPA ROD Standard and Guideline #7, on approximately 408 acres in four units in the Galloway area (Units 141, 142, 150, and 151). Figure 2 displays these treatment units in the Galloway area. Consistent with project-specific forest plan amendment TERR-NORTH YUBA-MA-01 (Final EIS Appendix B), a silviculturist has reviewed field conditions in these four units. Stands within these four units are extremely dense and at risk of imminent tree mortality. Data collected in these stands show basal area averaging 400 square feet per acre with a stand density index (SDI) of 550, which is 120 percent of the maximum SDI for mixed conifer stands.6 (To avoid substantial tree mortality, SDI levels should be below 50 percent of a maximum SDI of 450 for mixed conifer stands in
this Landscape, i.e. SDI of 225 or less.7) These stands have between 36 and 44 trees per acre 30 inches dbh or larger,8 and approximately 57 to 67 percent of the trees between 30 and 39.9 inches are shade tolerant conifers9. Large pines within these stands are either dead or at high risk of loss due to high stand densities and there is the possibility of immediate, short- and long-term mortality of fir. At least half of the largest shade intolerant pines and some Douglas-fir trees have already died in these units. White fir is experiencing disease and density related mortality as well, and will continue to see high mortality rates due to root disease as the other species die out. Extensive tree mortality in these units may result in complete large tree stand loss over time without appropriate treatment, including removal of some shade tolerant conifers between 30 and 39.9 inches dbh. Removing some shade tolerant conifers in this size class is needed to retain and promote the growth of larger shade-intolerant trees by more effectively meeting project objectives for tree species composition and forest stand density. An estimated average of 2 to 8 shade tolerant trees between 30 and 39.9 inches dbh per acre could be removed, leaving an estimated average of 30 to 36 trees per acre greater than 30 inches dbh on site. Shade tolerant trees selected for removal would generally be of low vigor (less than 30 percent crown ratio), and reductions in overstory canopy cover would be limited. Removal of some shade tolerant trees between 30 and 39.9 inches in these stands would effectively reduce stand densities within approximately 55 percent of5 Prescribed fire is not proposed as a follow up treatment for thinning on any of the 345 acres of hydraulic mine sites in the
Galloway and Rattlesnake Skinner areas.
6 Silviculture/Forest Health Technical Report, pg. 20 and pp. 30 -32
7 Silviculture/Forest Health Technical Report, pg.9
8 Silviculture/Forest Health Technical Report, pg. 28
9 North Yuba Drone Based Stand Mapping (available in the Project Record)
Record of Decision – North Yuba Landscape Resilience Projectmaximum SDI, thereby largely mitigating density-related tree mortality, including loss of large pines. In contrast, applying a 30-inch diameter limit in these four units would continue to keep stand density levels in the zone of imminent tree mortality (greater than 70 percent maximum SDI) following thinning.10
Opportunities to create 1- to 3-acre openings to enhance stand structural heterogeneity are extremely limited in these four units due to the high density of trees greater than or equal to 30 inches dbh, TERR- NORTH YUBA-STD-01 could be used to create approximately four to eight 1-acre openings across the four units due to the high densities of trees (30 inches dbh and greater) in these units.
Is that enough explanation? Seemingly the same discussion (if considered sufficient) could be made (in an appendix to) an EA or a CE.
It’s also of interest that four forests to the north of the Tahoe, with similar PP/true fir combos, the forests are required to follow the E side screens “21 inch rule.”
Is that because the Forests (and scientist amicus-filers) didn’t adequately argue their case? The absence of a relevant GTR?
Or is it simply an artifact of vegetation management by courts?

