                  FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

THE LANDS COUNCIL, a Washington        
nonprofit corporation; OREGON
WILD, an Oregon nonprofit
corporation; HELLS CANYON
PRESERVATION COUNCIL, an Oregon
nonprofit corporation, and SIERRA
CLUB, a California corporation,
              Plaintiffs-Appellants,
                 v.
KEVIN MARTIN, Forest Supervisor
of the Umatilla National Forest
U.S. Forest Service, and the                 No. 07-35804
UNITED STATES FOREST SERVICE, an
agency of the United States                   D.C. No.
                                           CV-06-00229-LRS
Department of Agriculture,                    OPINION
             Defendants-Appellees,
                and
AMERICAN FOREST RESOURCE
COUNCIL, an Oregon corporation;
BOISE BUILDING SOLUTIONS
MANUFACTURING, L.L.C., a
Washington limited liability
company; DODGE LOGGING, INC., an
Oregon corporation,
           Defendants-Intervenors-
                          Appellees.
                                       
        Appeal from the United States District Court
          for the Eastern District of Washington
         Lonny R. Suko, District Judge, Presiding

                            7383
7384           THE LANDS COUNCIL v. MARTIN
                 Argued and Submitted
            March 11, 2008—Portland, Oregon

                   Filed June 25, 2008

       Before: Susan P. Graber, Richard A. Paez, and
               Carlos T. Bea, Circuit Judges.

                 Opinion by Judge Graber
                 THE LANDS COUNCIL v. MARTIN               7387


                         COUNSEL

Ralph O. Bloemers, Crag Law Center, Portland, Oregon, for
the plaintiffs-appellants.

David C. Shilton, United States Department of Justice, Envi-
ronment & Natural Resources Division, Washington, D.C.,
for the defendants-appellees.

Scott W. Horngren, Haglund Kelley Horngren Jones & Wil-
der, LLP, Portland, Oregon, for the defendants-intervenors-
appellees.


                          OPINION

GRABER, Circuit Judge:

   A forest fire burned thousands of acres of national forest in
southeastern Washington, the United States Forest Service
initiated a salvage logging operation, and we are called upon
to determine whether the Forest Service took the requisite
“hard look” under the National Environmental Policy Act of
7388                THE LANDS COUNCIL v. MARTIN
1969 (“NEPA”), 42 U.S.C. §§ 4321-4370, and whether it
complied with the National Forest Management Act of 1976
(“NFMA”), 16 U.S.C. §§ 1600-1614.

   Plaintiffs The Lands Council, Oregon Wild, Hells Canyon
Preservation Council, and Sierra Club, which are environmen-
tal organizations, appeal the district court’s grant of summary
judgment to Defendants United States Forest Service and the
Forest Supervisor of the Umatilla National Forest. American
Forest Resource Council, Boise Building Solutions Manufac-
turing, L.L.C., and Dodge Logging, Inc., which are a forestry
advocacy organization and logging companies, join Defen-
dants as intervenors. We hold that the Forest Service failed to
include an adequate discussion of the effects of proposed log-
ging on two significant roadless areas. We otherwise affirm.

         FACTUAL AND PROCEDURAL HISTORY

   In August 2005, a forest fire named the “School Fire”
burned approximately 51,000 acres in southeastern Washing-
ton, including 28,000 acres of the Umatilla National Forest.
Soon thereafter, the Forest Service began preparations for the
School Fire Salvage Recovery Project, to harvest trees located
within the burned areas of National Forest lands. After two
rounds of public comments, the Forest Service released the
final Environmental Impact Statement (“EIS”) and issued a
record of decision.

  The Forest Service chose the alternative in the EIS that per-
mitted salvage logging on 9,423 acres. None of the proposed
logging would occur on land designated as an inventoried
roadless area.1 The proposed logging would occur, however,
  1
    Large areas of land without roads, called “roadless areas,” have been
the subject of congressional and executive study. In the 1970s, the federal
government undertook a comprehensive cataloguing effort of roadless
areas that resulted in the designation of many roadless areas as “invento-
ried.” See generally Nat’l Audubon Soc’y v. U.S. Forest Serv., 46 F.3d
1437, 1439-40 (9th Cir. 1993) (describing this history).
                    THE LANDS COUNCIL v. MARTIN                       7389
on portions of two uninventoried roadless areas, known infor-
mally as the West Tucannon roadless area (4,284 acres) and
the Upper Cummins Creek roadless area (966 acres). Both of
those uninventoried roadless areas lie adjacent to, but on dif-
ferent sides of, the Willow Springs inventoried roadless area
(which contains more than 12,000 acres). West Tucannon and
Willow Springs are separated by a road. Upper Cummins
Creek and Willow Springs are not separated by a road; those
areas in combination therefore comprise a contiguous roadless
expanse of more than 13,000 acres.

   Because trees that are damaged or destroyed by fire depre-
ciate in value quickly, the Forest Service Chief issued an
Emergency Situation Determination pursuant to 36 C.F.R.
§ 215.10 in the summer of 2006. That Determination autho-
rized immediate logging in three designated areas, premised
on the prediction that “a delay would result in a potential loss
of value of $1,547,000 to the Federal Government.”

   On August 15, 2006, one day after the issuance of the
record of decision, Plaintiffs filed suit, alleging violations of
NEPA and NFMA. The district court denied Plaintiffs’
motion for a temporary restraining order and preliminary
injunction. A divided three-judge panel of this court denied
Plaintiffs’ emergency motion for an injunction pending
appeal, and a logging operation commenced. This court expe-
dited the appeal and, after hearing oral argument in February
2007, we affirmed in part and reversed in part. Lands Council
v. Martin, 479 F.3d 636 (9th Cir. 2007) (as amended). We
reversed the district court’s denial of a preliminary injunction
on Plaintiff’s NFMA claim concerning the Forest Service’s
interpretation of the term “live trees” in the Umatilla National
Forest Land and Resource Management Plan (“Forest Plan”).
Id. at 641-43. The term appears in the portion of the Forest
Plan known as the “Eastside Screens.”2 Id. at 641 & n.5. The
  2
    The Eastside Screens are a set of interim riparian, ecosystem, and wild-
life standards for timber sales applicable to public lands east of the Cas-
7390               THE LANDS COUNCIL v. MARTIN
Eastside Screens require that the Forest Service “[m]aintain
all remnant late and old seral and/or structural live trees
[greater than or equal to] 21″ dbh [diameter at breast height]
that currently exist within stands proposed for harvest activi-
ties.” Id. at 641 (emphasis omitted). In short, the Forest Plan
prohibits the harvest of old-growth “live trees.”

   Plaintiffs argued that the Forest Service’s proposed logging
of dying trees violated the Eastside Screens because dying
trees are still alive. We agreed:

        We apply the common meaning of the term “live
     trees” because neither the NFMA nor the applicable
     Forest Plan defines the term. The common under-
     standing of the term “live” is, quite simply, “not
     dead.” Accordingly, the common meaning of the
     term “all . . . live trees” is all trees that have not yet
     died.

        . . . Applying this definition, “live trees” will be
     harvested, which is expressly prohibited by the East-
     side Screens.

        The Forest Service tries to escape this simple for-
     mulation by arguing that the term “live trees” is a
     technical term understood by foresters to exclude
     dying trees and that we must defer to its technical
     expertise. We need not decide whether, in theory, we
     must employ a technical definition in a Forest Plan
     because there is no evidence in this record that the
     Forest Service adopted a technical meaning. Not

cade Mountains, which are set forth in the Forest Service’s
“Environmental Assessment for the Continuation of Interim Management
Direction Establishing Riparian, Ecosystem, and Wildlife Standards for
Timber Sales,” appendix B, June 1995. Lands Council, 479 F.3d at 641
n.5. They were incorporated into the Forest Plan through Umatilla Forest
Plan Amendment #11.
                 THE LANDS COUNCIL v. MARTIN                   7391
    only are the NFMA and the Forest Plan silent on the
    definition of “live trees,” but neither the Forest Ser-
    vice nor Intervenors have cited any authoritative def-
    inition of the term “live trees.” The Forest Service
    introduced evidence of a practice of harvesting
    dying trees, but that does not establish a technical
    definition of the term “live trees.” Foresters very
    well may consider dying trees suitable for logging,
    but on this record we cannot conclude that they con-
    sider dying trees not “live.” . . . The Forest Service
    is free, of course, to amend the Eastside Screens to
    allow logging of old-growth dying trees, either by
    adding a definition of the term “live trees” or by
    changing the requirement to maintain all live trees of
    a certain size. Unless and until it does so, there is no
    basis to adopt its proposed definition.

Id. at 642-43.

   Plaintiffs also argued that the EIS’ discussion of the West
Tucannon and Upper Cummins Creek roadless areas was
inadequate to meet the requirements of NEPA. Because of the
demanding standard of review on appeal from the district
court’s denial of a preliminary injunction, we affirmed: “Al-
though Plaintiffs may ultimately succeed on the merits, we
hold that the district court did not abuse its discretion in deny-
ing Plaintiffs’ motion for injunctive relief.” Id. at 639-40.

  On remand, the district court issued an injunction prohibit-
ing the cutting of any live tree 21″ or more in diameter at
breast height. The salvage logging operation authorized by the
Emergency Situation Determination continued, albeit now
constrained in that one respect. The Forest Service also began
a new public notice and comment process aimed at supple-
menting the EIS with a new definition of “live trees.”

   On June 11, 2007, the Forest Service released a final Sup-
plemental Environmental Impact Statement and issued a
7392             THE LANDS COUNCIL v. MARTIN
record of decision. The selected alternative amended the East-
side Screens’ prohibition against harvesting old-growth live
trees by adding a definition of “live trees.” The new definition
excluded dying trees, using a predictive method known as the
“Scott Mortality Guidelines.”

   The Supplemental Environmental Impact Statement estab-
lished certain desirable criteria for the best predictive model
for the School Fire Salvage Recovery Project. In particular,
the Forest Service sought a method that would apply to wild-
fires, address all of the principal commercial species of trees
within the project area, be valid for the geographic area of the
project, and be operationally practical to potentially evaluate
hundreds of trees per acre, over thousands of acres. The For-
est Service rejected a handful of other predictive models and
concluded that, “[i]n the context of the School Fire Salvage
Recovery Project, we believe that the Scott Guidelines are
more appropriate for predicting tree mortality than any of the
alternative models individually.”

   The Forest Service limited the scope of the amendment to
the geographic area, and for the duration, of the School Fire
Salvage Recovery Project. The Forest Supervisor stated in the
record of decision:

    My decision amends the Umatilla National Forest’s
    Land and Resource Management Plan Eastside
    Screens’ wildlife standard at 6d.(2)(a) to read as fol-
    lows:

            Maintain all remnant late and old seral
         and/or structural live trees [greater than or
         equal to] 21″ dbh that currently exist within
         stands proposed for harvest activities. Live
         trees are defined as trees rated to have a
         high probability of surviving the effects of
         fire, and trees rated to have a moderate
         probability of survival where sampling
                    THE LANDS COUNCIL v. MARTIN                       7393
           indicates that at least 50 percent of their
           basal cambium is alive. Dead trees are
           defined as trees rated to have a low proba-
           bility of surviving the effects of fire, and
           trees rated to have a moderate probability
           of survival where sampling indicates that
           more than 50 percent of their basal cam-
           bium is dead. Survival probability is deter-
           mined using [the Scott Mortality
           Guidelines].

      This amendment applies to, and only for the duration
      of, the site-specific project called School Fire Sal-
      vage Recovery Project.

(Italicization omitted.) The Forest Supervisor further
explained that the amendment was chosen because the com-
mon meaning of the term “live trees” “does not reflect Forest
Service silvicultural practice and interpretation, and it deters
the Forest Service from achieving the purpose and need of the
School Fire Salvage Recovery Project.” The Forest Supervi-
sor found that the site-specific amendment was not “signifi-
cant” due to the limited temporal and geographic scope.
Finally, the Forest Service issued a second Emergency Situa-
tion Determination. That Determination permitted logging
under the amended Eastside Screens in four timber sales
areas.

   On September 17, 2007, the district court granted summary
judgment to Defendants on all claims. Plaintiffs timely
appealed, and the district court issued an injunction pending
appeal. In this appeal, Plaintiffs challenge three aspects of the
School Fire Salvage Recovery Project: the new definition of
“live trees” in the Eastside Screens, the soil analysis in the
EIS, and the discussion of roadless areas in the EIS.3
  3
   Before the district court, Plaintiffs challenged several other aspects of
the Forest Service’s actions, including whether the EIS considered a rea-
7394                THE LANDS COUNCIL v. MARTIN
                   STANDARDS OF REVIEW

  We review de novo the district court’s grant of summary
judgment. Or. Natural Res. Council Fund v. Goodman, 505
F.3d 884, 888-89 (9th Cir. 2007).

     Agency decisions that allegedly violate NEPA and
     NFMA are reviewed under the Administrative Pro-
     cedure Act (“APA”) and may be set aside only if
     they are arbitrary, capricious, an abuse of discretion,
     or otherwise not in accordance with law. Although
     our review under this standard is deferential, the
     agency must nonetheless articulate a rational connec-
     tion between the facts found and the conclusions
     made. Moreover, if an agency fails to consider an
     important aspect of a problem . . . or offers an expla-
     nation for the decision that is contrary to the evi-
     dence, its action is arbitrary and capricious.

Id. at 889 (citations, internal quotation marks, and alterations
omitted).

                            DISCUSSION

  A.    The New Definition of “Live Trees”

   Plaintiffs raise a number of challenges to the new definition
of “live trees.” Plaintiffs first argue that the amendment to the
Eastside Screens is arbitrary and capricious because the new
definition of “live trees” represents a change in policy, and
the Forest Service did not provide a reasonable explanation
for this change in policy. Because the result is the same either
way, we assume that the definition reflects a change in policy.

sonable range of alternatives, whether the EIS correctly analyzed the eco-
nomic costs and benefits of the project, whether the record of decision
contained factual misrepresentations, and whether the EIS complied with
the Forest Plan’s snag retention requirements. Plaintiffs do not appeal the
district court’s rulings on those issues.
                 THE LANDS COUNCIL v. MARTIN                 7395
   In Morales-Izquierdo v. Gonzales, 486 F.3d 484, 493 (9th
Cir. 2007) (en banc) (as amended), we emphasized that “an
‘unexplained inconsistency is . . . a reason for holding an
interpretation to be an arbitrary and capricious change [in pol-
icy].’ ” (Quoting Nat’l Cable & Telecomms. Ass’n v. Brand X
Internet Servs., 545 U.S. 967, 981 (2005)) (alterations omit-
ted) (emphasis by Morales-Izquierdo). We clarified, however,
that that rule “is reserved for rare instances, such as when an
agency provides no explanation at all for a change in policy,
or when its explanation is so unclear or contradictory that we
are left in doubt as to the reason for the change in direction.”
Id. As we have noted, “Chevron itself involved a 180-degree
reversal in an agency’s position that survived judicial scruti-
ny.” Id.; see also Brand X, 545 U.S. at 981-82 (observing the
same).

   [1] Here, the Forest Service explained that it was amending
the Forest Plan because the plain-text definition of “live trees”
“does not reflect Forest Service silvicultural practice and
interpretation, [and] frustrates the ability of the Forest Service
to achieve the purpose and need of the School Fire Salvage
Recovery Project.” Plaintiffs disagree with that explanation
on the merits, but the Forest Service clearly offered a rational
explanation, and we are not “left in doubt as to the reason for
the change in direction.” Morales-Izquierdo, 486 F.3d at 493.
We therefore conclude that the Forest Service’s amendment
to the Eastside Screens is not one of those “rare instances” in
which the agency’s action is arbitrary and capricious for fail-
ure to provide an adequate explanation.

   Our conclusion is unchanged by Plaintiffs’ affidavits from
respected scientists in the field, which assert that the new def-
inition of “live trees” is not properly supported by science. In
other words, Plaintiffs dispute the “silvicultural practice and
interpretation” of the Forest Service and prefer their experts’
interpretation over the Forest Service experts’ interpretation.
We are unmoved. “When specialists express conflicting
views, an agency must have discretion to rely on the reason-
7396                THE LANDS COUNCIL v. MARTIN
able opinions of its own qualified experts even if, as an origi-
nal matter, a court might find contrary views more
persuasive.” Marsh v. Or. Natural Res. Council, 490 U.S.
360, 378 (1989). We have applied that general principle in the
context of a dispute concerning a Forest Plan provision: “We
are in no position to resolve this dispute because we would
have to decide that the views of [the plaintiffs’] experts have
more merit than those of the Forest Service’s experts.” Inland
Empire Pub. Lands Council v. Schultz, 992 F.2d 977, 981 (9th
Cir. 1993) (brackets and internal quotation marks omitted);
see also Bear Lake Watch, Inc. v. Fed. Energy Reg. Comm’n,
324 F.3d 1071, 1077 (9th Cir. 2003) (“[A]lthough a party[ ]
‘has demonstrated that some scientists dispute the Service’s
analyses and conclusions, such a showing is not a sufficient
basis for us to conclude that the Service’s action was arbitrary
or capricious. If it were, agencies could only act upon achiev-
ing a degree of certainty that is ultimately illusory.’ ” (quoting
Greenpeace Action v. Franklin, 14 F.3d 1324, 1336 (9th Cir.
1992) (as amended)).

   [2] That same principle applies to Plaintiffs’ challenge to
the particular methodology chosen here: the Scott Mortality
Guidelines. “We will not second-guess methodological
choices made by an agency in its area of expertise.” Inland
Empire, 992 F.2d at 981. Plaintiffs urge that this is not a typi-
cal dispute about methodology. They argue that the Forest
Service is required to use a scientific methodology, which
requires, at a minimum, peer review or publication. They next
point out that the EIS itself states that “[t]he Scott Guidelines
were apparently not peer-reviewed or published in a credible
source.”

   [3] We find no legal requirement that a methodology be
“peer-reviewed or published in a credible source.” Plaintiffs
cite 40 C.F.R. §§ 1500.1(b) and 1502.24, but those regula-
tions contain no such requirements and do not even mention
peer review or publication.4 The Forest Service has explained
  4
   Section 1500.1(b) states in full:
       NEPA procedures must insure that environmental information
                    THE LANDS COUNCIL v. MARTIN                      7397
that the Scott Mortality Guidelines are derived from field test-
ing and practical experience. We do not find arbitrary the For-
est Service’s choice to rely on those verification techniques in
lieu of peer review and publication when verifying the scien-
tific basis of a relatively new methodology. Cf. Baltimore Gas
& Elec. Co. v. Natural Res. Def. Council, Inc., 462 U.S. 87,
103 (1983) (holding that, “at the frontiers of science, . . . a
reviewing court must generally be at its most deferential”).

   Plaintiffs next argue that the Forest Service “has manufac-
tured a gap in the Forest Plan.” Under Plaintiffs’ view, the
Forest Service is bound to the common meaning of the term
“live trees.” We disagree. The text of a statute binds an
agency if it unambiguously expresses congressional intent.
Chevron U.S.A. Inc. v. Natural Res. Def. Council, Inc., 467
U.S. 837, 842-43 (1984). But the Forest Service’s action in
this case is amendment of a forest plan, not interpretation of
a statutory term. Congress has expressed no view on the defi-
nition of “live trees.” No statute or precedent of which we are
aware suggests that a previously undefined technical term in
a forest plan can never be clarified through amendment sim-
ply because the technical definition conflicts with the dictio-
nary definition.

    is available to public officials and citizens before decisions are
    made and before actions are taken. The information must be of
    high quality. Accurate scientific analysis, expert agency com-
    ments, and public scrutiny are essential to implementing NEPA.
    Most important, NEPA documents must concentrate on the issues
    that are truly significant to the action in question, rather than
    amassing needless detail.
Section 1502.24 states in full:
      Agencies shall insure the professional integrity, including sci-
    entific integrity, of the discussions and analyses in environmental
    impact statements. They shall identify any methodologies used
    and shall make explicit reference by footnote to the scientific and
    other sources relied upon for conclusions in the statement. An
    agency may place discussion of methodology in an appendix.
7398                THE LANDS COUNCIL v. MARTIN
  Plaintiffs’ final arguments concern the procedure that the
Forest Service employed to amend the Forest Plan. The Forest
Service did not amend the entire Eastside Screens with the
new definition of “live trees.” Instead, it expressly limited the
amendment “to, and only for the duration of, the site-specific
project called School Fire Salvage Recovery Project.”
Because of the limited scope of the amendment, the Forest
Supervisor concluded that the amendment was not “signifi-
cant.”

   [4] Under the relevant statute and regulation, the correct
procedure depends on the scope of the amendment: “Signifi-
cant” amendments require a lengthy and detailed amendment
process; otherwise, a simpler notice and comment process
suffices. 16 U.S.C. § 1604(f)(4); 36 C.F.R. § 219.10(f) (2000).5
Specifically, the statute provides that, if the Forest Service
chooses to amend a forest plan, the forest plan “shall . . . be
amended in any manner whatsoever after final adoption after
public notice, and, if such amendment would result in a sig-
nificant change in such plan, [after procedures in addition to
public notice have taken place].” 16 U.S.C. § 1604(f)(4).

   [5] The “regulations leave to the discretion of the Forest
Service the question of whether any given amendment is sig-
nificant.” Native Ecosystems Council v. Dombeck, 304 F.3d
886, 900 (9th Cir. 2002); see also 36 C.F.R. § 219.10(f)
(2000) (“[T]he Forest Supervisor shall determine whether a
proposed amendment would result in a significant change in
  5
    The 2000 version of the regulations applies to the amendment in this
case. The regulations governing the correct procedure for plan amend-
ments have changed over the years. Current regulations establish a “transi-
tion period” between January 5, 2005, and January 7, 2008. 36 C.F.R.
§ 219.14(b). “Plan amendments initiated during the transition period may
continue using the provisions of the planning regulations in effect before
November 9, 2000 . . . .” Id. § 219.14(d)(2). The Forest Service initiated
the amendment to the Eastside Screens in the spring of 2007, within the
transition period, and chose the option of applying the 2000 version of the
regulations. No party contends that this choice was improper.
                 THE LANDS COUNCIL v. MARTIN               7399
the plan.”). Here, consistent with other significance determi-
nations and the Forest Service Handbook, the Forest Supervi-
sor considered the four factors listed in the Forest Service
Handbook: timing; location and size; goals, objectives, and
outputs; and “management prescription” (defined as whether
the change applies only to a specific situation or will affect
future decisions as well). Forest Service Handbook 1909.12,
ch. 5.31; see also Prairie Wood Prods. v. Glickman, 971 F.
Supp. 457, 463 (D. Or. 1997) (observing that “[t]he Forest
Service Handbook . . . provides guidelines for determining
whether a forest plan amendment is significant” and listing
the four factors); Citizens’ Comm. to Save Our Canyons v.
U.S. Forest Serv., 297 F.3d 1012, 1033 (10th Cir. 2002)
(“Although the Forest Supervisor has wide discretion in
deciding whether an amendment is significant, the [Forest
Service Handbook] outlines factors the Supervisor must con-
sider when assessing the significance of a proposed amend-
ment, including [the four factors].”). We therefore reject
Plaintiffs’ challenge to the Forest Supervisor’s conclusion that
the amendment is not significant, to the extent that Plaintiffs
simply disagree with the Forest Supervisor’s conclusion.

   Plaintiffs also argue that the Forest Service arbitrarily
enacted a site-specific amendment, particular to this salvage
project, rather than a general amendment, applicable to all
parts of the forest. In Native Ecosystems, we addressed a simi-
lar argument. The forest plan at issue in that case restricted
road density to ensure sufficient elk habitat. Native Eco-
systems, 304 F.3d at 890-91. Rather than close roads, the For-
est Service passed a site-specific amendment that exempted
the challenged timber sale from the road-density requirement.
Id. at 891. The Forest Service concluded that the requirement
was not necessary to ensure sufficient elk habitat and that the
requirement was not reasonable as applied to the given timber
sale. Id. at 898. Although identical site-specific amendments
were planned for other timber sales in the forest, we held that
the Forest Service’s decision to analyze each amendment sep-
arately was “reasonable.” Id. at 900.
7400             THE LANDS COUNCIL v. MARTIN
   We recognized that the Forest Service’s decision to limit
the scope of an amendment to a particular site could be arbi-
trary. Id. We concluded, however, that waiver of the particu-
lar requirement, due to site-specific characteristics and based
on the Forest Service’s expertise, was reasonable, even
though waiver of the same requirement appeared likely in
other timber sales. Id.

   Similarly, in Wyoming Sawmills Inc. v. United States For-
est Service, 383 F.3d 1241, 1250-51 (10th Cir. 2004), the For-
est Service concluded that only 18,000 acres of land would be
affected by its amendment and determined that the amend-
ment was not “significant.” The plaintiff argued that the For-
est Service’s significance determination was flawed because,
in fact, the affected area was much greater. Id. at 1251-52.
The Tenth Circuit recognized that a significance determina-
tion could be arbitrary but held that the plaintiff’s arguments
on the size of the affected area failed to overcome the Forest
Service’s expertise on this issue. Id. at 1252. Again, site-
specific characteristics and Forest Service expertise were the
lynchpins of the deference afforded the Forest Service’s sig-
nificance determination.

   [6] Here, as in Native Ecosystems and Wyoming Sawmills,
the Forest Service’s decision to limit the scope of the amend-
ment was informed by site-specific characteristics and Forest
Service expertise. In particular, the Forest Service chose a
definition that assesses the effects of a wildfire on the species
of trees found in the affected forest. Evidence in the record
suggests that the chosen definition may not be appropriate to
assess trees affected by prescribed burning, flooding, disease,
insect infestation, or any number of other causes of tree mor-
tality. We therefore hold that the Forest Service “articulated
a rational connection between the facts found and the choice
made.” Pac. Coast Fed’n of Fishermen’s Ass’n v. Nat’l
Marine Fisheries Serv., 265 F.3d 1028, 1034 (9th Cir. 2001)
(as amended) (internal quotation marks omitted).
                    THE LANDS COUNCIL v. MARTIN                         7401
  B.    Soil Analysis in the EIS

   [7] Plaintiffs next challenge three aspects of the soil analy-
sis in the EIS. Plaintiffs first contend that the Forest Service
did not conduct an on-the-ground soil analysis as required by
Ninth Circuit precedent.6 See Lands Council v. Powell, 395
F.3d 1019, 1034-35 (9th Cir. 2005) (as amended) (holding
that the Forest Service’s reliance on a spreadsheet model for
soil conditions violated NFMA because “[t]he Forest Service
did not walk, much less test, the land in the activity area”);
Ecology Ctr., Inc. v. Austin, 430 F.3d 1057, 1070-71 (9th Cir.
2005) (applying Powell). We are not persuaded. The EIS con-
tains a 15-page analysis of soils, in which there are several
references to field verification and observation. See, e.g., EIS
at 3-8 (“It was evident during field assessments that some of
the existing condition estimates will overstate the existing
[detrimental soil conditions] in some cases.” (emphasis
added)); EIS 3-9 (“Soil characteristics were field verified by
the Forest Soil Scientist at the harvest unit scale.” (emphasis
added)); EIS 3-10 (“Units for School Fire Salvage Recovery
Project were assessed for the extent and degree of previously
effected soil using field observation starting in the fall of
2005, the soil inventory (SRI) with field verification by the
Forest Soil Scientist. . . .” (emphases added)). Those state-
ments in the EIS, representing that field verification actually
occurred, distinguish this case from Ecology Center and Pow-
ell. See Wildwest Inst. v. Bull, 472 F.3d 587, 591-92 (9th Cir.
2006) (distinguishing those cases on the basis of reports of
field verification).
  6
    This court recently granted en banc review of the continuing vitality of
the on-the-ground rule cited by Plaintiffs. Lands Council v. McNair, 494
F.3d 771 (9th Cir. 2007), reh’g en banc granted, 512 F.3d 1204 (9th Cir.
2008); see also id., 494 F.3d at 780-86 (M. Smith, J., specially concurring)
(criticizing the rule announced in Powell and Ecology Center). Because
we hold that the soil analysis in the EIS is sufficient even under the current
rule, we need not defer submission until en banc resolution of McNair.
7402            THE LANDS COUNCIL v. MARTIN
   Plaintiffs make a number of technical arguments purporting
to demonstrate that, despite the assertions contained in the
EIS, the Forest Service must not have actually performed on-
the-ground soil analysis. Their arguments constitute sophisti-
cated speculation, but nothing in the record proves that the
Forest Service did not do the on-the-ground analysis that it
reported.

   Plaintiffs next argue that the Forest Service improperly
interpreted the term “severe burning” in a provision of the
Forest Plan. The provision requires the Forest Service to
“[p]lan and conduct land management activities so that reduc-
tions of soil productivity potential caused by detrimental com-
paction, displacement, puddling, and severe burning are
minimized.” Also, the Forest Service Manual contains a rele-
vant provision:

       Leave a minimum of 80% of an activity area in an
    acceptable soil quality condition. Detrimental condi-
    tions, as defined below, also include landings and
    system roads. Detrimental soil quality conditions and
    the accompanying criteria for determining when and
    where these conditions occur include:

      a. Compaction, Displacement, Puddling,
    Severely Burned.

       ....

       (4) Detrimental Burned Soil. Soils are considered
    to be detrimentally burned when the mineral soil sur-
    face has been significantly changed in color, oxi-
    dized to a reddish color, and the next one-half inch
    blackened from organic matter charring by heat con-
    ducted through the top layer. The detrimentally
    burned soil standard applies to an area greater than
    100 square feet, which is at least five feet in width.
                 THE LANDS COUNCIL v. MARTIN                7403
The EIS interprets those provisions to apply only to
management-induced burns, not forest fires. Its soil analysis
therefore did not account for the burning effects of the forest
fire.

   [8] Plaintiffs argue that the provisions should be read to
include both artificially induced and naturally occurring
effects. We are unpersuaded. Especially given the context of
the provisions, aimed at “land management activities” and
“activity areas,” it is plausible to read the quoted provision as
limited to management-induced effects. In any event, we can-
not say that the Forest Service’s interpretation is plainly erro-
neous or otherwise inconsistent. See Forest Guardians v. U.S.
Forest Serv., 329 F.3d 1089, 1097 (9th Cir. 2003) (“[J]udicial
review of an agency’s interpretation of its own regulations is
limited to ensuring that the agency’s interpretation is not
plainly erroneous or inconsistent with the regulation.”).

   Plaintiffs’ final argument is that the Forest Service imper-
missibly used the “long-term average annual prediction”
method instead of Plaintiffs’ preferred “return period analysis
for soil erosion” method. As stated above, “[w]e will not
second-guess methodological choices made by an agency in
its area of expertise.” Inland Empire, 992 F.2d at 981. In addi-
tion, Plaintiffs concede that Dr. Elliot is the premier expert in
this area of soil analysis, and the record contains a declaration
by Dr. Elliot that Plaintiffs’ preferred method is “seldom
used” and tends to produce incorrectly high results.

   [9] In summary, we affirm the district court’s holding that
the EIS’s soil analysis violates neither NEPA nor NFMA.

  C.   Roadless Area Analysis in the EIS

   Citing Smith v. United States Forest Service, 33 F.3d 1072
(9th Cir. 1994), and National Audubon Society v. United
States Forest Service, 46 F.3d 1437 (9th Cir. 1993), Plaintiffs
argue that the EIS violates NEPA because it does not contain
7404             THE LANDS COUNCIL v. MARTIN
an adequate discussion of the effects of the proposed logging
on the roadless character of two substantial roadless areas.
West Tucannon roadless area is a bounded uninventoried
roadless area that contains 4,284 acres. Upper Cummins
Creek roadless area is an uninventoried roadless area that con-
tains 966 acres but, when combined with the adjacent Willow
Springs inventoried roadless area, forms a “roadless expanse”
of more than 13,000 acres. See Smith, 33 F.3d at 1078 (refer-
ring to a contiguous area comprised of an uninventoried road-
less area and an inventoried roadless area as a “roadless
expanse”).

   [10] In Smith, 33 F.3d at 1078-79, we held that there are at
least two separate reasons why logging in roadless areas is
environmentally significant, so that its environmental conse-
quences must be considered. First, roadless areas have certain
attributes that must be analyzed. Those attributes, such as
water resources, soils, wildlife habitat, and recreation oppor-
tunities, possess independent environmental significance. Sec-
ond, roadless areas are significant because of their potential
for designation as wilderness areas under the Wilderness Act
of 1964, 16 U.S.C. §§ 1131-1136. Lands Council, 479 F.3d at
640; Smith, 33 F.3d at 1078-79.

   [11] Plaintiffs do not challenge the EIS’s discussion of the
attributes of the roadless areas. Instead, they argue that the
EIS does not comply with the requirement in Smith that the
roadless areas be discussed in the context of their potential for
wilderness designation. In Smith, we held that “the possibility
of future wilderness classification triggers, at the very least,
an obligation on the part of the agency to disclose the fact that
development will affect a 5,000 acre roadless area.” 33 F.3d
at 1078. Defendants respond that the EIS is sufficient
because, unlike the roadless area at issue in Smith, each road-
less area here is uninventoried and contains less than 5,000
acres. We hold that those characteristics do not provide a
meaningful legal distinction from the roadless area in Smith.
                 THE LANDS COUNCIL v. MARTIN                 7405
   [12] The Upper Cummins Creek roadless area is indistin-
guishable from the roadless area at issue in Smith. In Smith,
we considered an uninventoried roadless area of approxi-
mately 4,000 acres that was contiguous to an inventoried
roadless area of approximately 2,000 acres. 33 F.3d at 1077.
Logging was scheduled to occur only in the uninventoried
land, but we concluded nevertheless that the area must be ana-
lyzed as one combined roadless area of more than 6,000 acres.
Id. at 1077-78 & n.3. Here, the Upper Cummins Creek road-
less area contains approximately 1,000 acres of uninventoried
land and is contiguous to an inventoried roadless area of
approximately 12,000 acres. Following Smith, we consider the
Upper Cummins Creek roadless area not in isolation, but in
combination with the contiguous inventoried roadless area. It
is undisputed that this “roadless expanse” contains more than
5,000 acres.

   [13] Additionally, the Wilderness Act does not limit the
potential for wilderness designation to roadless areas 5,000
acres or larger. The Act states that an area is suitable for wil-
derness designation if it meets several requirements, including
that the area “has at least five thousand acres of land or is of
sufficient size as to make practicable its preservation and use
in an unimpaired condition.” 16 U.S.C. § 1131(c) (emphasis
added). As we explained in the original appeal, “[t]he Wilder-
ness Act does not require an absolute minimum of 5,000
acres; it also allows for designation where the area ‘is of suffi-
cient size as to make practicable its preservation and use in an
unimpaired condition.’ ” Lands Council, 479 F.3d at 640
(quoting 16 U.S.C. § 1131(c)).

   [14] The roadless area in Smith, of course, contained more
than 5,000 acres, so naturally we discussed the issues by ref-
erence to “a 5,000 acre roadless area.” But the foundation for
the rule—the potential for wilderness designation under the
Wilderness Act—demonstrates that the rule applies with
equal force to roadless areas “of sufficient size as to make
practicable its preservation and use in an unimpaired condi-
7406             THE LANDS COUNCIL v. MARTIN
tion.” 16 U.S.C. § 1131(c). In particular, we hold that “the
possibility of future wilderness classification triggers, at the
very least, an obligation on the part of the agency to disclose
the fact that development will affect a 5,000 acre roadless
area,” Smith, 33 F.3d at 1078, or will affect an area of suffi-
cient size as to make practicable its preservation and use in an
unimpaired condition. We need not explore the smallest pos-
sible area that would be “sufficient” under the statute; we are
confident on this record that the 4,284-acre West Tucannon
roadless area is of sufficient size to fall within the rule.

   [15] In summary, the Forest Service was required to discuss
the effects of the proposed logging on the roadless character
of both roadless areas. Smith held that the size of an uninven-
toried roadless area must be considered in combination with
the size of any contiguous inventoried roadless area. The size
of Upper Cummins Creek combined with the size of contigu-
ous Willow Springs is more than 5,000 acres. We make clear
today that the rule in Smith applies to roadless areas that are
either greater than 5,000 acres or of a “sufficient size” within
the meaning of 16 U.S.C. § 1131(c). The West Tucannon
roadless area falls within the scope of that rule.

   Defendants next argue that, even if the Forest Service was
required to include a discussion of the roadless areas, the EIS
in fact includes such a discussion. The EIS does contain a
three-page analysis on “roadless character,” but the cursory
nature of the discussion and legal errors in it render it insuffi-
cient to meet the requirements of NEPA.

   In three separate passages, the EIS erroneously declares
that 5,000 acres is an absolute minimum size criterion for
potential designation as a wilderness area. See EIS at 3-270
(“There are no other areas within the School Fire Salvage
Recovery Project area that meet or exceed the 5,000 acre size
criteri[on] for roadless.”); id. (“There are no large blocks of
land where the undeveloped character of the area meets the
minimum criteri[on] of 5,000 acres or greater that might make
                    THE LANDS COUNCIL v. MARTIN                         7407
them potentially designated as an [inventoried roadless area]
or wilderness area.”); id. at 3-271 (“There would be no direct,
indirect, or cumulative effects to alter the undeveloped char-
acter of any land because there are no large blocks that meet
the minimum criteri[on] of 5,000 acres or greater.”). The EIS
erroneously adds that “[n]or are there areas of undeveloped
character adjacent to an existing [inventoried roadless area] or
wilderness area suitable for consideration.” Id.; see also id. at
3-270 (nearly identical statement).

   Wholly apart from those errors, we conclude that the EIS’s
discussion fails to meet even the bare minimum requirement
discussed in Smith and analyzed above: “the possibility of
future wilderness classification triggers, at the very least, an
obligation on the part of the agency to disclose the fact that
development will affect a 5,000 acre roadless area.” Smith, 33
F.3d at 1078 (emphasis added). Upper Cummins Creek, com-
bined with the contiguous inventoried roadless area, com-
prises one roadless area much larger than 5,000 acres. That
fact is nowhere revealed in the EIS. As in Smith, “nowhere
has the agency disclosed that the inventoried and uninvento-
ried lands together comprise one 5,000 acre roadless area.” Id.
at 1079. Similarly, the West Tucannon roadless area contains
nearly 5,000 acres (i.e., is “of sufficient size”) but the EIS
never discloses that fact.7

   [16] In conclusion, we reverse the district court’s holding
that the EIS’s discussion of the effects of the proposed log-
  7
    It is true, of course, that the EIS contains a map and other data describ-
ing where the proposed logging will occur. From that information, it is
possible (as Plaintiffs have done) to piece together where logging will
occur, where roadless areas are located, and where the two intersect. But
such data are always present, as they were in Smith. Smith requires that the
agency disclose that significant roadless areas will be affected and take the
requisite “hard look” at the environmental consequences of that fact. The
bare data that allow the public to discover that, contrary to the assertions
in the EIS, significant roadless areas will be affected is insufficient.
7408            THE LANDS COUNCIL v. MARTIN
ging in the roadless areas complied with the requirements of
NEPA. We affirm the district court in all other respects.

  AFFIRMED in part, REVERSED in part, and
REMANDED. The parties shall bear their own costs on
appeal.
