The Lands Council v. McNair

We took this case en banc to clarify some of our environmental jurisprudence with respect to our review of the actions of the United States Forest Service.

The Lands Council and Wild West Institute (collectively, Lands Council) moved for a preliminary injunction to halt the Mission Brush Project (the Project), which called for the selective logging of 3,829 acres of forest in the Idaho Panhandle National Forest (IPNF). As the basis for the preliminary injunction, Lands Council claimed that Ranotta McNair and the United States Forest Service (collectively, the Forest Service), failed to comply with the National Forest Management Act (NFMA), 16 U.S.C. § 1600 et seq., the National Environmental Policy Act (NEPA), 42 U.S.C. § 4231 et seq., and the Administrative Procedure Act (APA), 5 U.S.C. § 701 et seq., in developing and implementing the Project.

Boundary County, City of Bonners Ferry, City of Moyie Springs, Everhart Logging, Inc., and Regehr Logging, Inc. (collectively, Intervenors) intervened on behalf of the Forest Service. The district court denied Lands Council’s motion for a preliminary injunction. A three-judge panel of this court reversed the district court’s decision and remanded for entry of a preliminary injunction in Lands Council v. McNair, 494 F.3d 771 (9th Cir.2007). We vacate that decision and affirm the district court.

I. FACTUAL AND PROCEDURAL BACKGROUND

A. Mission Brush Area

The Mission Brush Area (or Project Area) encompasses approximately 31,350 acres and is located in the northeastern portion of the Bonners Ferry Ranger District. Approximately 16,550 acres of the Project Area are National Forest System lands, which are home to a variety of species (or their habitats), including the northern gray wolf, Canada lynx, grizzly bear, black-backed woodpecker, flammu-lated owl, fisher, western toad, pileated woodpecker, and the white-tailed deer. The Project Area is also home to old-growth trees.

*985 The current structure and composition of the forest in the Project Area differs significantly from the forest’s historic composition. While the Project Area previously consisted of relatively open ponderosa pine and Douglas-fir stands, today it is crowded with stands of shade-tolerant, younger Douglas-firs and other mid-to-late-suceessional species. The suppression of naturally occurring fires, past logging practices, and disease are primarily responsible for this shift in forest composition.

The increased density of trees has proven deleterious to the old-growth trees and the Project Area’s ecology. First, old-growth trees need relatively open conditions to survive and maintain their growth rates. Second, the increased density is causing a decline in the health and vigor of all trees because they must compete for moisture, sunlight, and nutrients, and the densely clustered trees are less tolerant of insects and disease. Third, dense, dry forests are at risk for large, stand-replacing fires, due to the build-up of fuels. Lastly, wildlife species that prefer a relatively open forest composition with more old-growth trees have suffered a decline in habitat.

B. Mission Brush Project

The Forest Service proposed the Project, in part, to restore the forest to its historic composition, which, in the Forest Service’s assessment, is more likely to be sustainable over time. But this is not the Project’s only objective. According to the Supplemental Final Environmental Impact Statement (SFEIS) that the Forest Service issued in April 2006, the overall “objectives of the project are to begin restoring forest health and wildlife habitat, improv[e] water quality and overall aquatic habitat by reducing sediment and the risk of sediment reaching streams, and provid[e] recreation opportunities that meet the varied desires of the public and the agency while reducing negative effects to the ecosystem.” The Project proposes to accomplish these varied objectives through a number of actions, such as improving roads that presently contribute to sediment in the watersheds, decommissioning roads posing a great risk of contributing to sediment, ensuring that the Project Area has acceptable toilets and wheelchair accessible pathways to toilets, installing a boat ramp and fishing dock, and improving trails.

After considering multiple approaches on how best to accomplish the Project’s goals with respect to forest composition, including one no-action alternative, the Forest Service chose to implement a modified version of Alternative 2. In relevant part, Alternative 2 calls for silvicultural treatments on 3,829 acres of forest, fuels treatments on 3,698 acres, and ecosystem burns without harvest on 238 acres. The silvicultural treatments proposed include commercial thinning, 1 regeneration cuts, 2 and sanitation salvage harvesting. 3

*986 As a part of the Project, the Forest Service plans to treat 277 acres of dry-site old-growth stands in order to increase the overall quality of dry-site old-growth stands and scattered old-growth Douglas-fir, and to improve and maintain trees that could be old-growth in the future. Despite its plans to perform treatments within old-growth stands, the Project will not involve harvesting allocated old-growth trees. The Forest Service represented in the SFEIS that the allocated old-growth in the IPNF has not been harvested for several years, and that its “focus is on maintaining [existing] old growth stands ... and allocating additional stands for future old growth as they mature.” In those units containing old-growth trees, the Forest Service has identified those non-old-growth trees it plans to harvest.

The Project is expected to generate 23.5 million board feet of timber, which has been, or will be, sold pursuant to three timber sale contracts: the Brushy Mission Sale, the Haller Down Sale, and the Mission Fly By Sale. The Forest Service sold the Brushy Mission Sale to Everhart Logging, and the Haller Down Sale to Regehr Logging. The Forest Service received no bids for the Mission Fly By Sale, which contains all but fourteen of the old-growth acres that are part of the Haller Down Sale. Though logging under the Brushy Mission and Haller Down sales has already begun, the injunction imposed by the district court pursuant to the three-judge panel opinion in Lands Council, 494 F.3d 771, prohibits the Forest Service from logging in the fourteen acres of old-growth in the Haller Down Sale. The same injunction imposes other restrictions on the Forest Service, including a prohibition on taking any action in the area encompassed by the Mission Fly By Sale.

C. Procedural History

In late 2002, the Forest Service decided to undertake management activities in the Mission and Brush Creek areas. In 2003, the Forest Service issued a draft Environmental Impact Statement (EIS). After receiving public comments, the Forest Service released its final EIS and Record of Decision (ROD) in June 2004. Lands Council appealed the ROD. The Forest Service upheld the Project, but ordered the preparation of a supplemental EIS in light of this court’s decision in Lands Council v. Powell (Lands Council I), 379 F.3d 738 (9th Cir.2004), amended by 395 F.3d 1019 (9th Cir.2005), which addressed the management of National Forest System lands in the IPNF in connection with a different Forest Service project. The Forest Service subsequently released a supplemental draft EIS for public comment, and issued the SFEIS and ROD in April 2006. Lands Council and other environmental groups filed an administrative appeal, which the Forest Service denied in July 2006. In October 2006, Lands Council filed this action and moved for a preliminary injunction.

II. STANDARD OF REVIEW AND JURISDICTION

We have jurisdiction to review a district court’s denial of a preliminary injunction under 28 U.S.C. § 1292(a)(1). A district court’s decision regarding preliminary injunctive relief is subject to “limited and deferential” review. Sw. Voter Registration Educ. Project v. Shelley, 344 F.3d 914, 918 (9th Cir.2003) (en banc) (per cu-riam). Thus, we review the denial of a preliminary injunction for abuse of discretion. Earth Island Inst. v. U.S. Forest Serv. (Earth Island Inst. II), 442 F.3d 1147, 1156 (9th Cir.2006).

A district court abuses its discretion in denying a request for a preliminary injunction if it “base[s] its decision on an erroneous legal standard or clearly erroneous findings of fact.” Id. (citation omitted). We review conclusions of law de novo and *987 findings of fact for clear error. Id. Under this standard, “[a]s long as the district court got the law right, it will not be reversed simply because the appellate court would have arrived at a different result if it had applied the law to the facts of the case.” Id. (quoting Earth Island Inst. v. U.S. Forest Serv. (Earth Island Inst. I), 351 F.3d 1291, 1298 (9th Cir.2003)).

“A preliminary injunction is appropriate when a plaintiff demonstrates ‘either: (1) a likelihood of success on the merits and the possibility of irreparable injury; or (2) that serious questions going to the merits were raised and the balance of hardships tips sharply in [the plaintiffs] favor.’ ” Lands Council v. Martin (Lands Council II), 479 F.3d 636, 639 (9th Cir.2007) (quoting Clear Channel Outdoor Inc. v. City of Los Angeles, 340 F.3d 810, 813 (9th Cir.2003)). These two options represent extremes on a single continuum: “ ‘the less certain the district court is of the likelihood of success on the merits, the more plaintiffs must convince the district court that the public interest and balance of hardships tip in their favor.’ ” Id. (quoting Sw. Voter Registration Educ. Project, 344 F.3d at 918).

In deciding whether Lands Council is likely to succeed on the merits of its claims, we must remember that the APA provides the authority for our review of decisions under NEPA and NFMA. Pit River Tribe v. U.S. Forest Serv., 469 F.3d 768, 778 (9th Cir.2006). The APA states, in relevant part, that a reviewing court may set aside only agency actions that are “arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.” 5 U.S.C. § 706(2)(A).

Review under the arbitrary and capricious standard “is narrow, and [we do] not substitute [our] judgment for that of the agency.” Earth Island Inst. II, 442 F.3d at 1156 (ci ting U.S. Postal Serv. v. Gregory, 534 U.S. 1, 6-7, 122 S.Ct. 431, 151 L.Ed.2d 323 (2001)). Rather, we will reverse a decision as arbitrary and capricious only if the agency relied on factors Congress did not intend it to consider, “entirely failed to consider an important aspect of the problem,” or offered an explanation “that runs counter to the evidence before the agency or is so implausible that it could not be ascribed to a difference in view or the product of agency expertise.” Id. (citing Sierra Club v. U.S. Envtl. Prot. Agency, 346 F.3d 955, 961 (9th Cir.2003), amended by 352 F.3d 1186 (9th Cir.2003)). Thus, although we review the district court’s denial of Lands Council’s request for a preliminary injunction for abuse of discretion, our review of the district court’s determination as to whether Lands Council was likely to prevail on the merits of its NEPA and NFMA claims necessarily incorporates the APA’s arbitrary and capricious standard.

III. DISCUSSION

Lands Council argues that, in developing the Project, the Forest Service violated the NFMA in two ways: (1) by failing to demonstrate the reliability of the scientific methodology underlying its analysis of the Project’s effect on wildlife, (specifically the flammulated owl and its habitat), 4 and (2) *988 by not complying with Standard 10(b) of the IPNF Forest Plan, which requires the Forest Service to maintain at least ten percent old-growth throughout the forest. Lands Council also argues that the Forest Service violated NEPA because, in Lands Council’s view, the Forest Service did not adequately address the uncertainty concerning its proposed treatment as a strategy to maintain species viability.

In essence, Lands Council asks this court to act as a panel of scientists that instructs the Forest Service how to validate its hypotheses regarding wildlife viability, chooses among scientific studies in determining whether the Forest Service has complied with the underlying Forest Plan, and orders the agency to explain every possible scientific uncertainty. As we will explain, this is not a proper role for a federal appellate court. But Lands Council’s arguments illustrate how, in recent years, our environmental jurisprudence has, at times, shifted away from the appropriate standard of review and could be read to suggest that this court should play such a role.

Below, we address each of Lands Council’s arguments. We first discuss the language and purpose of the NFMA and how, in Ecology Center, Inc. v. Austin, 430 F.3d 1057 (9th Cir.2005), cert. denied, Mineral County v. Ecology Center, Inc., — U.S. -, 127 S.Ct. 931, 166 L.Ed.2d 702 (2007), we misconstrued what the NFMA requires of the Forest Service. We then turn to whether the Forest Service met the NFMA’s requirements in this case; specifically, we consider the sufficiency of the Forest Service’s analysis of the Project’s effect on the flammulated owl and its habitat, and whether the Forest Service has complied with Standard 10(b) of the IPNF Forest Plan. Next, we consider the statutory language and purpose of NEPA, and whether, in this case, the Forest Service’s alleged failure to discuss uncertainty regarding its strategy for species viability violated NEPA.

We are mindful, of course, that important environmental resources are at stake in cases such as this, and we strongly reaffirm that the Forest Service must fully comply with the requirements of the NFMA and NEPA. We conclude that the Forest Service has complied with those requirements in this case, and we affirm the district court’s denial of Lands Council’s request for a preliminary injunction.

A. The National Forest Management Act

1. Statutory Language And Purpose

The NFMA sets forth the statutory framework and specifies the procedural and substantive requirements under which the Forest Service is to manage National Forest System lands. Procedurally, the NFMA requires the Forest Service to develop a forest plan for each unit of the National Forest System. 16 U.S.C. § 1604(a). In developing and maintaining each plan, the Forest Service is required to use “a systematic interdisciplinary approach to achieve integrated consideration *989 of physical, biological, economic, and other sciences.” Id. § 1604(b). After a forest plan is developed, all subsequent agency action, including site-specific plans such as the Mission Brush Project, must comply with the NFMA and be consistent with the governing forest plan. Id. § 1604(i); see Idaho Sporting Cong., Inc. v. Rittenhouse, 305 F.3d 957, 962 (9th Cir.2002) (“[A]ll management activities undertaken by the Forest Service must comply with the forest plan, which in turn must comply with the Forest Act.” (citing Inland Empire Pub. Lands Council v. U.S. Forest Serv., 88 F.3d 754, 757 (9th Cir.1996))).

Substantively, the NFMA requires the Secretary of Agriculture to develop guidelines “to achieve the goals of the Program,” including:

[P]rovid[ing] for diversity of plant and animal communities based on the suitability and capability of the specific land area in order to meet overall multiple-use objectives, and within the multiple-use objectives of a land management plan adopted pursuant to this section, provide, where appropriate, to the degree practicable, for steps to be taken to preserve the diversity of tree species similar to that existing in the region controlled by the plan ...

16 U.S.C. § 1604(g)(3)(B); see Envtl. Prot. Info. Ctr. v. U.S. Forest Serv., 451 F.3d 1005, 1017 (9th Cir.2006) (“The NFMA imposes substantive duties on USFS, including the duty ‘to provide for diversity of plant and animal communities.’ ” (quoting 16 U.S.C. § 1604(g)(3)(B))). 5

The Project also must be consistent with the IPNF Forest Plan’s provisions regarding wildlife viability. See 16 U.S.C. § 1604(i). In the IPNF Forest Plan, the Forest Service designated the flammulat-ed owl, the only species at issue in this appeal, as a sensitive species. The IPNF Forest Plan requires the Forest Service to “[mjanage the habitat of species listed in the Regional Sensitive Species List to prevent further declines in populations which could lead to federal listing under the Endangered Species Act.” U.S. Dep’t of Agriculture, Forest Plan, Idaho Panhandle National Forests, at 11-28 (Aug. 1987), available at http://www.fs.fed.us/ *990 ipnf/eco/manage/forestplan/ [hereinafter IPNF Forest Plan].

Congress has consistently acknowledged that the Forest Service must balance competing demands in managing National Forest System lands. Indeed, since Congress’ early regulation of the national forests, it has never been the case that “the national forests were ... to be ‘set aside for non-use.’ ” United States v. New Mexico, 438 U.S. 696, 716 n. 23, 98 S.Ct. 3012, 57 L.Ed.2d 1052 (1978) (citing 30 Cong. Rec. 966 (1897) (statement of Rep. McRae)). For example, in the Organic Administration Act of June 4, 1897, passed less than a decade after Congress began regulating the national forests, Congress identified two purposes for which it would reserve a national forest at that time: “[to] securfe] favorable conditions of water flows, and to furnish a continuous supply of timber.” Id. at 707-08, 98 S.Ct. 3012 (quoting 16 U.S.C. § 475 (1976)).

Congress’ current vision of national forest uses, a broader view than Congress articulated in 1897, is expressed in the Multiple-Use Sustained Yield Act of 1960, 16 U.S.C. § § 528-31, which states that “[i]t is the policy of the Congress that the national forests are established and shall be administered for outdoor recreation, range, timber, watershed, and wildlife and fish purposes.” Id. § 528. The NFMA references 16 U.S.C. § § 528-531 and requires that plans developed for units of the National Forest System “provide for multiple use and sustained yield of the products and services obtained therefrom ... and [must] include coordination of outdoor recreation, range, timber, watershed, wildlife and fish, and wilderness[.]” Id. § 1604(e)(1). Thus, the NFMA is explicit that wildlife viability is not the Forest Service’s only consideration when developing site-specific plans for National Forest System lands.

2. We Overrule Ecology Center

Lands Council argues that the Forest Service violated the NFMA because it has not demonstrated the reliability of the scientific methodology underlying its analysis of the effect of the Project’s proposed treatment on the flammulated owl and its habitat. Relying primarily on Ecology Center, Lands Council specifically contends that the Forest Service erred by not verifying its prediction regarding the effect of treatment on old-growth species’ habitat with observation or on-the-ground analysis. We disagree, and hereby overrule Ecology Center. We also hold that the district court did not abuse its discretion in concluding that Lands Council is unlikely to succeed on the merits of this claim.

In Ecology Center, we relied on Lands Council I when we grafted onto our jurisprudence a broad rule that, in effect, requires the Forest Service to always “demonstrate the reliability of its scientific methodology” or the hypotheses underlying the Service’s methodology with “on the ground analysis.” See Ecology Ctr., 430 F.3d at 1064 (quoting Lands Council I, 379 F.3d at 752). Thus, our analysis begins with Lands Council I.

In Lands Council I, we reviewed the Forest Service’s approval of a timber harvest as part of a watershed restoration project in the IPNF. 395 F.3d at 1024. The project was “designed to improve the aquatic, vegetative, and wildlife habitat in the Project area.” Id. at 1025. Lands Council challenged that project’s compliance with the NFMA in part because it questioned the reliability of the Forest Service’s scientific methodology underlying its analysis of disturbed soil conditions. Id. at 1034.

In analyzing the quality of the soil in the project area, the Forest Service had not taken soil samples from the activity area, *991 but instead had relied on samples from other areas in the forest and on aerial photographs. Id. Despite the Forest Service’s representation that it had “tested similar soils within the Forest, and similar soils act the same way,” we rejected the Forest Service’s choice of scientific methodology because it was based entirely on a spreadsheet model with no on-site inspection or verification. Id. at 1034-35. We explained that “/ujnder the circumstances of this case, the Forest Service’s basic scientific methodology, to be reliable, required that the hypothesis and prediction of the model be verified with observation. The predictions of the model ... were not verified with on the ground analysis.” Id. at 1035 (emphasis added). We then held that the “Forest Service’s reliance on the spreadsheet models, unaccompanied by on-site spot verification of the model’s predictions, violated NFMA.” Id.

In Ecology Center, we applied an on-the-ground analysis requirement to our review of the Lolo National Forest Post Burn Project, in which the Forest Service proposed logging in old-growth forest and post-fire habitats. 430 F.3d at 1060. We held that in order to comply with the NFMA, the Forest Service was required to conduct on-the-ground analysis to verify its soil quality analysis and to establish the reliability of its hypothesis that “treating old-growth forest is beneficial to dependent species.” Id. at 1064, 1070-71.

Ecology Center even suggests that such an analysis must be on-site, meaning in the location of the proposed action. There, we rejected the Forest Service’s argument that its on-the-ground soil analysis was “sufficiently reliable because it utilized data from areas with ecological characteristics similar to the proposed harvest units.” Id. at 1070. We noted that, as in Lands Council I, the Forest Service had not tested “much of the activity area.” Id. (quoting Lands Council I, 395 F.3d at 1034) (emphasis added); see also Wildwest Inst. v. Bull, 472 F.3d 587, 591-92 (9th Cir.2006) (distinguishing Ecology Center because the Forest Service relied on on-site analysis in developing its proposal). But see Ecology Ctr., 430 F.3d at 1064 (noting that the Forest Service did not conduct on-the-ground analysis “despite the fact that it has already treated old-growth forest elsewhere and therefore had the opportunity to do so”).

We made three key errors in Ecology Center. First, we read the holding of Lands Council I too broadly. Second, we created a requirement not found in any relevant statute or regulation. And, third, we defied well-established law concerning the deference we owe to agencies and their methodological choices. Today, we correct those errors.

In Lands Council I, we expressly limited our holding that “on-site spot verification” was required for soil analysis to “the circumstances of [that] case.” 395 F.3d at 1036. But in Ecology Center, we expanded the on-the-ground analysis requirement beyond the facts of Lands Council I, and even beyond the context of soil analysis. In holding that the Forest Service violated the NFMA by not verifying its hypothesis that treating old-growth forest is beneficial to dependent species with on-the-ground analysis, Ecology Center established a far-reaching rule that the Forest Service must always verify its methodology with on-the-ground analysis, regardless of the context. 430 F.3d at 1064. We accept the description in Lands Council I that it was “limited to the circumstances of [that] case,” and hold that it does not impose a categorical requirement of on-the-ground analysis or observation for soil analysis, or any other type of analysis.

The Forest Service is at liberty, of course, to use on-the-ground analysis if it deems it appropriate or necessary, but it is *992 not required to do so. As Judge McKeown explained in her dissent in Ecology Center, “there is no legal basis to conclude that the NFMA requires an on-site analysis where there is a reasonable scientific basis to uphold the legitimacy of modeling. NFMA does not impose this substantive requirement, and it cannot be derived from the procedural parameters of NEPA.” 430 F.3d at 1073 (McKeown, J., dissenting); see also Inland Empire Pub. Lands Council, 88 F.3d at 758 (noting that NEPA imposes only procedural requirements on federal agencies).

The NFMA unquestionably requires the Forest Service to “provide for diversity of plant and animal communities ... in order to meet overall multiple-use objectives.” 16 U.S.C. § 1604(g)(3)(B). Similarly, the IPNF Forest Plan requires the Forest Service to “[m]anage the habitat of species listed in the Regional Sensitive Species List to prevent further declines in populations which could lead to federal listing under the Endangered Species Act.” IPNF Forest Plan, supra, at 11-28. However, despite imposing these substantive requirements on the Forest Service, neither the NFMA and its regulations 6 nor the IPNF Forest Plan specify precisely how the Forest Service must demonstrate that its site-specific plans adequately provide for wildlife viability.

Granting the Forest Service the latitude to decide how best to demonstrate that its plans will provide for wildlife viability comports with our reluctance to require an agency to show us, by any particular means, that it has met the requirements of the NFMA every time it proposes action. We have approved of forest plans when they are “based on the current state of scientific knowledge.” See Seattle Audubon Soc’y v. Moseley, 80 F.3d 1401, 1404 (9th Cir.1996). Moseley upheld a plan to manage old-growth forest after the plan was challenged on the grounds that the Forest Service did not adequately account for the northern spotted owl’s habitat. Id. We stated:

Here, the record demonstrates that the federal defendants considered the viability of plant and animal populations based on the current state of scientific knowledge. Because of the inherent flexibility of the NFMA, and because there is no showing that the federal defendants overlooked any relevant factors or made any clear errors of judgment, we conclude that their interpretation and application of the NFMA’s viability regulations was reasonable.

Id. (citations omitted). Thus, we defer to the Forest Service as to what evidence is, or is not, necessary to support wildlife viability analyses.

Were we to grant less deference to the agency, we would be ignoring the APA’s arbitrary and capricious standard of review. Ecology Center illustrates the consequences of failing to grant appropriate deference to an agency. In Ecology Cen *993 ter, we rejected reports establishing that soil analysis was conducted in the project area as “too few and of poor quality.” See 430 F.3d at 1073 (McKeown, J., dissenting). We stated, “[t]he record provides little information that enables us to assess the reliability or significance of these reports; for example, we do not know the qualifications of the person conducting the field review, the methodology utilized, or whether the field observations confirmed or contradicted the Service’s estimates.” Id. at 1070 (majority opinion). Essentially, we assessed the quality and detail of on-site analysis and made “fine-grained judgments of its worth.” Id. at 1077 (McKeown, J., dissenting). It is not our proper role to conduct such an assessment.

Instead, our proper role is simply to ensure that the Forest Service made no “clear error of judgment” that would render its action “arbitrary and capricious.” See Marsh v. Or. Natural Res. Council, 490 U.S. 360, 378, 109 S.Ct. 1851, 104 L.Ed.2d 377 (1989); see also Ecology Ctr., 430 F.3d at 1075 (McKeown, J., dissenting) (noting that Lands Council I did not demand that we “assess the sufficiency of the Forest Service’s on-site soil quality analysis beyond the traditional arbitrary and capricious standard; it only asks us to verify that there is such an on-site sampling”). To do so, we look to the evidence the Forest Service has provided to support its conclusions, along with other materials in the record, to ensure that the Service has not, for instance, “relied on factors which Congress has not intended it to consider, entirely failed to consider an important aspect of the problem, offered an explanation for its decision that runs counter to the evidence before the agency, or [an explanation that] is so implausible that it could not be ascribed to a difference in view or the product of agency expertise.” Motor Vehicle Mfrs. Assn., Inc. v. State Farm Mut. Auto. Ins. Co., 463 U.S. 29, 43, 103 S.Ct. 2856, 77 L.Ed.2d 443 (1983); see Lands Council I, 395 F.3d at 1026.

This approach respects our law that requires us to defer to an agency’s determination in an area involving a “high level of technical expertise.” See Selkirk Conservation Alliance v. Forsgren, 336 F.3d 944, 954 (9th Cir.2003) (quoting Marsh, 490 U.S. at 377-78, 109 S.Ct. 1851). We are to be “most deferential” when the agency is “making predictions, within its [area of] special expertise, at the frontiers of science.” Forest Guardians v. U.S. Forest Serv., 329 F.3d 1089, 1099 (9th Cir.2003) (citations omitted). A number of our sister circuits agree that we are to conduct a “particularly deferential review” of an “agency’s predictive judgments about areas that are within the agency’s field of discretion and expertise ... as long as they are reasonable.” EarthLink, Inc. v. FCC, 462 F.3d 1, 12 (D.C.Cir.2006) (quoting FCC v. WNCN Listeners Guild, 450 U.S. 582, 594, 101 S.Ct. 1266, 67 L.Ed.2d 521 (1981)); see Cellnet Commc’ns, Inc. v. FCC, 149 F.3d 429, 441 (6th Cir.1998); W. Fuels-Ill., Inc. v. ICC, 878 F.2d 1025, 1030 (7th Cir.1989).

Finally, this approach also acknowledges that “[w]e are not free to ‘impose on the agency [our] own notion of which procedures are ‘best’ or most likely to further some vague, undefined public good.’ ” Churchill County v. Norton, 276 F.3d 1060, 1072 (9th Cir.2001) (alteration in original) (quoting Vt. Yankee Nuclear Power Corp. v. Natural Res. Def. Council, Inc., 435 U.S. 519, 549, 98 S.Ct. 1197, 55 L.Ed.2d 460 (1978)). Nor may we impose “procedural requirements [not] explicitly enumerated in the pertinent statutes.” Wilderness Soc’y v. Tyrrel, 918 F.2d 813, 818 (9th Cir.1990).

Thus, as non-scientists, we decline to impose bright-line rules on the Forest *994 Service regarding particular means that it must take in every case to show us that it has met the NFMA’s requirements. Rather, we hold that the Forest Service must support its conclusions that a project meets the requirements of the NFMA and relevant Forest Plan with studies that the agency, in its expertise, deems reliable. The Forest Service must explain the conclusions it has drawn from its chosen methodology, and the reasons it considers the underlying evidence to be reliable. We will conclude that the Forest Service acts arbitrarily and capriciously only when the record plainly demonstrates that the Forest Service made a clear error in judgment in concluding that a project meets the requirements of the NFMA and relevant Forest Plan.

For these reasons, we overrule Ecology Center and affirm that Lands Council I’s requirement of on-the ground analysis was limited to the circumstances of that particular case.

3. Reliability of the Forest Service’s Analysis Concerning The Effects Of Treating Old-Growth Habitat On The Flammulated Owl

Lands Council argues that the Forest Service violated the NFMA by failing to demonstrate the reliability of the scientific methodology underlying its analysis of the Project’s effect on wildlife, specifically the flammulated owl and its habitat. But the Forest Service supported its conclusions about the impact of the Project on the flammulated owl and its habitat with studies it deemed reliable. Moreover, the Forest Service did conduct on-the-ground analysis of the flammulated owl in an area straddled by the Mission Brush Project Area, even though, by overruling Ecology Center, this opinion confirms that such analysis is not required. See supra Part III.A.2.

These studies, together with the Forest Service’s reasonable assumption that enhancing the amount of flammulated owl habitat in the long-term will maintain the flammulated owl populati