                  FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

THE ECOLOGY CENTER,                     
                           Plaintiff,
                and
WILDWEST INSTITUTE,
                Plaintiff-Appellant,           No. 07-35054
                 v.                              D.C. No.
BOB CASTANEDA, in his official              CV-06-00024-DWM
capacity as Forest Supervisor for                ORDER
the Kootenai National Forest;                  AMENDING
ABIGAIL KIMBALL, Regional                     OPINION AND
Forester of Region One of the                  DENYING
U.S. Forest Service; UNITED                  PETITION FOR
STATES FOREST SERVICE, an agency            REHEARING AND
of the U.S. Department of                    PETITION FOR
Agriculture,                                 REHEARING EN
             Defendants-Appellees,             BANC AND
                and                            AMENDED
                                                OPINION
F.H. STOLTZE LAND & LUMBER
CO.; FOUSTS INC.; REGEHR LOGGING
INC.; PONDERAY VALLEY FIBRE INC.;
LINCOLN COUNTY,
             Defendant-Intervenors.
                                        
      Appeal from the United States District Court
              for the District of Montana
    Donald W. Molloy, Chief District Judge, Presiding

                  Argued and Submitted
          January 20, 2009—Seattle, Washington

                            9393
9394           WILDWEST INSTITUTE v. CASTANEDA
                    Filed April 17, 2009
                   Amended July 22, 2009

    Before: Thomas M. Reavley,* Senior Circuit Judge,
Richard C. Tallman and Milan D. Smith, Jr., Circuit Judges.

                 Opinion by Judge Tallman




  *The Honorable Thomas M. Reavley, Senior United States Circuit
Judge for the Fifth Circuit, sitting by designation.
9398          WILDWEST INSTITUTE v. CASTANEDA




                        COUNSEL

Thomas J. Woodbury, Missoula, Montana, for the appellant.

John T. Stahr (briefed), and Charles R. Scott (argued), U.S.
Department of Justice Environment and Natural Resources
Division, Washington, D.C., for the appellees.
               WILDWEST INSTITUTE v. CASTANEDA             9399
                           ORDER

  The opinion filed on April 17, 2009, is amended as follows:

   The second paragraph of subsection <E. Population Viabil-
ity>, appearing at slip op. pages 4450-51, beginning <Wild-
West first claims the minimum . . .> and ending <. . . at least
134 breeding pairs> is DELETED and REPLACED with the
following:

   WildWest first claims the minimum viable population for
the pileated woodpecker in the KNF is 554 breeding pairs,
which represents forty percent of the 1384 pairs the KNF was
historically able to support. However, as WildWest notes in
its brief, the KNF was historically able to support a range of
335 to 1384 pairs. WildWest does not explain why the stan-
dard must be forty percent of the range’s upper limit. The For-
est Service calculated the viability threshold as a range of 335
to 554 breeding pairs, based on historical data. The lower
bound of 335 pairs is reasonable. The potential population
was at some time reduced to 335 pairs due to natural distur-
bances. From that nadir, the estimated population has since
grown larger. Therefore, the population was necessarily via-
ble at 335 pairs. The upper bound of 554 pairs represents forty
percent of the KNF’s historical maximum potential, as sug-
gested by the Forest Plan. Therefore, this range of 335 to 554
pairs is a reasonable interpretation of the Forest Plan’s provi-
sions for maintaining species viability. The KNF is currently
home to 425 breeding pairs of woodpeckers, well within the
permissible range, and the Forest Service’s determinations in
this respect were not arbitrary or capricious.

  The panel has voted to deny the petition for panel rehear-
ing. Judges Tallman and M. Smith have voted to deny the
petition for rehearing en banc and Judge Reavley so recom-
mends.
9400          WILDWEST INSTITUTE v. CASTANEDA
  The full court has been advised of the petition for rehearing
en banc and no judge has requested a vote on whether to
rehear the matter en banc. Fed. R. App. P. 35.

  The petition for panel rehearing and the petition for rehear-
ing en banc are denied.




                         OPINION

TALLMAN, Circuit Judge:

   WildWest Institute (“WildWest”) challenges the United
States Forest Service’s approval of nine timber sale and resto-
ration projects in Montana’s Kootenai National Forest
(“KNF”), claiming violations of the National Forest Manage-
ment Act (“NFMA”), the National Environmental Policy Act
(“NEPA”), and Forest Service regulations. WildWest sought
declaratory and injunctive relief to prevent environmental
injury. The district court granted summary judgment in favor
of the Forest Service. We have jurisdiction under 28 U.S.C.
§ 1291, and we affirm.

             I.   Facts and Prior Proceedings

   The KNF covers over 2.2 million acres in northwest Mon-
tana. The Forest Service adopted the Kootenai National Forest
Plan (“Forest Plan”) pursuant to NFMA in 1987. It is intended
to guide “all natural resource management activities and
establishes management standards” for the forest. The Forest
Plan establishes 23 Management Areas (“MA”) within the
KNF, including one related to Old Growth Timber (“MA
13”).

   To implement the Forest Plan, the Forest Service adopts
plans and projects for specific areas of the KNF. Over the
               WILDWEST INSTITUTE v. CASTANEDA               9401
course of 2004 and 2005, the Forest Service adopted the nine
site-specific projects that are challenged here: the Bristow
Area Restoration Project, Fortine Project, West Troy Project,
Pipestone Timber Sale and Restoration Project, Lower Big
Creek Project, South McSwede Timber Sale and Restoration
Project, Alder Creek Project, Cow Creek Project, and McSut-
ten Project. For each project, the Forest Service conducted an
extensive environmental analysis, including a draft and final
environmental impact statement (“DEIS” and “FEIS”) or an
environmental assessment.

   WildWest filed this action challenging the nine projects on
numerous grounds. The district court denied WildWest’s
motion for a preliminary injunction. The parties filed cross-
motions for summary judgment, and the district court granted
summary judgment in favor of the Forest Service. Wildwest
Inst. v. Castaneda, 462 F. Supp. 2d 1150, 1163 (D. Mont.
2006). The district court noted that, on many of its claims,
WildWest had failed to “establish[ ] a connection between the
challenged forest-wide management practices and the lawful-
ness of the logging projects.” Id. at 1157. Regarding those
claims properly raised, the district court concluded the Forest
Service had complied with the relevant procedural and sub-
stantive legal requirements. Id. at 1158-63. WildWest timely
appealed.

                  II.   Standard of Review

  We review the district court’s grant of summary judgment
de novo. McFarland v. Kempthorne, 545 F.3d 1106, 1110 (9th
Cir. 2008).

   The Administrative Procedure Act (“APA”) provides the
authority for our review of decisions under NEPA and
NFMA. Lands Council v. McNair (Lands Council II), 537
F.3d 981, 987 (9th Cir. 2008) (en banc). Under the APA, an
agency decision will be set aside only if it is “arbitrary, capri-
cious, an abuse of discretion, or otherwise not in accordance
9402           WILDWEST INSTITUTE v. CASTANEDA
with law.” 5 U.S.C. § 706(2)(A); see Ecology Ctr., Inc. v.
Austin, 430 F.3d 1057, 1062 (9th Cir. 2005). “Review under
the arbitrary and capricious standard ‘is narrow, and [we do]
not substitute [our] judgment for that of the agency.’ ” Lands
Council II, 537 F.3d at 987 (quoting Earth Island Inst. v. U.S.
Forest Serv., 442 F.3d 1147, 1156 (9th Cir. 2006)) (alterations
in original). “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. (quoting Earth
Island Inst., 442 F.3d at 1156).

                      III.   Background

A.     Governing Provisions

   [1] The National Forest Management Act, 16 U.S.C.
§§ 1600 et seq., provides both procedural and substantive
requirements. Procedurally, it requires the Forest Service to
develop and maintain forest resource management plans. Id.
§ 1604(a). After a forest plan is developed, all subsequent
agency action, including site-specific plans like the nine proj-
ects challenged here, must comply with NFMA and the gov-
erning forest plan. Id. § 1604(i); see Lands Council II, 537
F.3d at 989.

   [2] Substantively, NFMA requires that forest plans “pro-
vide for diversity of plant and animal communities based on
the suitability and capability of the specific land area.” 16
U.S.C. § 1604(g)(3)(B). Forest plans must also ensure that
timber will be harvested only where “soil, slope or other
watershed conditions will not be irreversibly damaged,” and
provide protection for streams from “detrimental” deposits of
sediment “where harvests are likely to seriously and adversely
affect water conditions or fish habitat.” Id. § 1604(g)(3)(E).
                 WILDWEST INSTITUTE v. CASTANEDA                  9403
   [3] The National Environmental Policy Act, 42 U.S.C.
§§ 4321 et seq., contains additional procedural requirements.
Its purposes are to ensure the decision-maker will have
detailed information on environmental impacts and to provide
that information to the public. Inland Empire Pub. Lands
Council v. U.S. Forest Serv., 88 F.3d 754, 758 (9th Cir. 1996).
The Forest Service must prepare an EIS, which identifies
environmental effects and alternative courses of action, when
undertaking any management project. Id.; 42 U.S.C.
§ 4332(c). “In contrast to NFMA, NEPA exists to ensure a
process, not to mandate particular results.” Neighbors of
Cuddy Mountain v. Alexander, 303 F.3d 1059, 1063 (9th Cir.
2002). The agency must only take a “hard look” at its pro-
posed action. Id. at 1070.

   [4] Two Forest Service regulations also apply here. The
“1982 Rule” requires the Forest Service to identify and moni-
tor management indicator species (“MIS”) and directs that
“fish and wildlife habitat shall be managed to maintain viable
populations of existing native and desired non-native verte-
brate species.” 47 Fed. Reg. 43048 (Sept. 30, 1982). The KNF
Forest Plan incorporated this and several other provisions of
the 1982 Rule.

   [5] The 1982 Rule was partially superceded in 2000 (the
“2000 Rule”). The 2000 Rule’s substantive provisions did not
apply to site-specific decisions made between 2000 and 2005.
69 Fed. Reg. 58,055-58 (Sept. 29, 2004). The “transition”
portions of the rule, which did apply during this time, required
the responsible officials to consider the “best available sci-
ence” when implementing existing land and resource manage-
ment plans. 36 C.F.R. § 219.35(a) (2001); 69 Fed. Reg.
58,057 (Sept. 29, 2004). The requirements of the superceded
1982 Rule apply only to the extent they were incorporated
into the Forest Plan.1 See generally Citizens for Better For-
  1
   The Department of Agriculture promulgated another regulation in
2005, which focused on forest-level planning. 70 Fed. Reg. 1022 (Jan. 5,
9404              WILDWEST INSTITUTE v. CASTANEDA
estry v. U.S. Dep’t of Ag., 341 F.3d 961, 966-68 (9th Cir.
2003) (discussing in detail the provisions of the 1982 and
2000 Rules).

B.     The Forest Plan

   The Forest Plan establishes twenty-four long-term goals,
including “provid[ing] a sustained yield of timber volume
responsive to national and regional needs” and “construct[ing]
the minimum number of roads necessary to permit the effi-
cient removal of timber and mineral resources.” With respect
to old-growth management, the goals also include “maintain[-
ing] diverse age classes of vegetation for viable populations
of all existing native, vertebrate, wildlife species,” and
“manag[ing] for sufficient snags and snag replacement trees
to maintain viable populations of snag-dependent species.”
With respect to fisheries and aquatic habitat, the Forest Plan
goals include “maintain[ing] or enhanc[ing] fisheries habitat.”
The Forest Plan also designates eight MIS that are monitored
as a barometer of change for a particular habitat. The pileated
woodpecker is the MIS for old-growth dependent species.

   Under the Forest Plan, the KNF is managed for two kinds
of old growth: undesignated and designated. Undesignated old
growth consists of naturally-occurring stands in nondevelop-
mental areas such as wilderness and primitive recreation
areas. Designated old growth, on the other hand, consists of
“existing old growth and some mature stands” in areas that
the Forest Service actively manages. Each category of old
growth—undesignated and designated—is sub-categorized
into “effective” old growth and “replacement” old growth.

2005). On March 30, 2007, a district court issued a nationwide injunction
prohibiting application of the rule. Ctr. for a Better Forestry v. U.S. Dep’t
of Ag., 481 F. Supp. 2d 1059 (N.D. Cal. 2007). Three of the projects chal-
lenged here were implemented while the 2005 rule was still in effect, but
WildWest does not claim the Forest Service violated any part of the 2005
Rule.
               WILDWEST INSTITUTE v. CASTANEDA             9405
Effective old growth presently meets the needs of old-growth
species; replacement old growth does not presently meet those
needs, but may do so in the future as trees grow and the habi-
tat ages.

   Old growth areas that have been designated are assigned
for management purposes to MA 13, which describes substan-
tive and procedural guidelines for the care of old growth. The
Forest Plan requires that “[a] minimum of 10 percent of the
Forest acreage below 5,500 feet elevation will provide old-
growth habitat at any given time in a combination of unde-
signated and designated old growth in well distributed and
sufficiently large stands.” The MA 13 guidelines reiterate this
ten percent goal.

C.   Connection to Site-Specific Projects

   As a preliminary matter, we note that we are precluded
from reviewing a number of WildWest’s allegations because,
as the district court properly found, they are not tied to site-
specific challenges. Forest-wide management practices and
monitoring efforts, or lack thereof, are generally not amenable
to suit under the APA because they do not constitute final
agency actions. Neighbors of Cuddy Mountain, 303 F.3d at
1067 (citing Lujan v. Nat’l Wildlife Fed’n, 477 U.S. 871, 891
(1990); Ecology Ctr., 192 F.3d at 925-26); see 5 U.S.C. § 704.
Challenges to forest-wide management practices or claims
that the Forest Plan does not comply with NFMA must be
made in the context of site-specific actions. Ohio Forestry
Ass’n, Inc. v. Sierra Club, 523 U.S. 726, 734 (1998). The
plaintiff must allege a “specific connection” between the chal-
lenged site-specific action and the general practice. Id.

   The district court noted that “[t]o the extent [WildWest]
attempts to challenge forest-wide management practices on
the coattails of the nine challenged logging projects, its suit
is generally permitted.” Wildwest Inst., 462 F. Supp. 2d at
1157. However, the court concluded the suit failed to estab-
9406           WILDWEST INSTITUTE v. CASTANEDA
lish connections between the general management practices
and the lawfulness of the logging projects. Many of Wild-
West’s myriad arguments and allegations on appeal suffer the
same defect. We address only those claims that WildWest has
plausibly connected to a site-specific action.

                     IV.   NFMA Claims

A.     Best Available Science

   WildWest’s first claim relates to the 2000 Rule’s “best
available science” requirement. This claim argues the best
available science undermines the assumption that ten percent
old-growth forest levels are sufficient to ensure species viabil-
ity. WildWest claims that a 1995 study (the “Lesica study”)
demonstrated that historic levels of old growth in the KNF
were “magnitudes of order” higher than the ten percent level
established under the Forest Plan. WildWest claims that
study’s estimate that “20-50% of low and mid-elevation for-
ests were in old-growth condition prior to European settle-
ment” represents the best available science and must be
reflected in the Forest Plan. WildWest also claims the Forest
Service’s own experts acknowledge historical conditions
“probably provided” a higher level of old-growth habitat,
though no such statement appears on the cited page of the
record. WildWest ties this general complaint only to the
Lower Big Creek Project.

   [6] We grant considerable discretion to agencies on matters
“requir[ing] a high level of technical expertise.” Marsh v. Or.
Natural Res. Council, 490 U.S. 360, 377 (1989). Though a
party may cite studies that support a conclusion different from
the one the Forest Service reached, it is not our role to weigh
competing scientific analyses. Lands Council II, 537 F.3d at
988 (noting that we do not “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
              WILDWEST INSTITUTE v. CASTANEDA             9407
the underlying Forest Plan, and orders the agency to explain
every possible scientific uncertainty”); Greenpeace Action v.
Franklin, 14 F.3d 1324, 1333 (9th Cir. 1992) (“To set aside
the Service’s determination in this case would require us to
decide that the views of Greenpeace’s experts have more
merit than those of the Service’s experts, a position we are
unqualified to take.”).

   [7] The 1982 Rule, as incorporated into the Forest Plan,
requires only that the Forest Service maintain habitat capable
of supporting “viable populations” of old-growth dependent
species. Relying on the best available science, as required by
the 2000 Rule, the Forest Service determined that maintaining
old-growth levels of ten percent below 5500 feet was suffi-
cient to support such species. The Forest Service’s analysis of
the scientific basis and reasoning for the ten percent standard
are set forth in the Old Growth Habitat Characteristics and
Management Guidelines (the “Old Growth Guidelines”) and
the Forest Plan FEIS. These documents discuss various char-
acteristics of old-growth dependent species and their habitat,
citing numerous scientific studies, along with competing
interests and practical concerns. The Old Growth Guidelines
conclude that “[a] review of applicable literature on wildlife
species and their habitat needs indicated that a minimum of 8-
10 percent of available wildlife habitat should provide old
growth conditions.” We hold the Forest Service met the best
available science requirement when it initially established the
ten percent old growth standard.

   [8] Moreover, WildWest has not cited any scientific studies
that indicate the Forest Service’s analysis is outdated or
flawed. See Oregon Trollers Ass’n v. Gutierrez, 452 F.3d
1104, 1120 (9th Cir. 2006) (rejecting best science claim
where “[t]here [was] no evidence in the record the [agency’s]
1986 and 1988 studies [were] outdated or flawed”) (citations
omitted). WildWest cites repeatedly to the Lesica study,
which was published after the Forest Service adopted the For-
est Plan. However, Lesica’s conclusion does not bear directly
9408           WILDWEST INSTITUTE v. CASTANEDA
on the “viable population” standard. The fact that levels of
old-growth forest were significantly higher prior to European
settlement in no way disproves the conclusion that ten percent
is enough to support “viable populations.”

   [9] The Forest Service reviewed its management situation
in 1993, proposing several changes based on new scientific
data from the intervening years. That review acknowledges
that recent research had shown “certain forest cover types are
not as well represented as they were historically,” a conclu-
sion similar to the one reached in the Lesica study. The Forest
Service’s 1993 review suggested several changes to the man-
agement strategy. However, alteration of the ten percent stan-
dard was not one of them. The Forest Service has carefully
considered the relevant scientific studies released since the
Forest Plan was adopted. We will not second guess the Forest
Service’s scientific analysis. See Lands Council II, 537 F.3d
at 988.

   In short, the Forest Service established the ten percent stan-
dard based on reasoned analysis of the best available science.
The Forest Service has also considered new relevant scientific
data since the Forest Plan was adopted in 1987. WildWest has
failed to indicate any scientific information directly under-
mining the conclusion that ten percent old-growth levels are
insufficient to support “viable populations” of dependent spe-
cies. Accordingly, we conclude that the best available science
supports the ten percent standard, and that the standard is
therefore not arbitrary or capricious.

B.     Designation of Old Growth: Stand Size

   WildWest next challenges the designation of tree stands
smaller than fifty acres as old-growth habitat. WildWest
argues that the Forest Plan requires stands of no less than fifty
acres and encourages blocks of one hundred acres or more. It
claims roughly one-third of the blocks of old growth currently
               WILDWEST INSTITUTE v. CASTANEDA             9409
designated in Pipestone, Bristow, and South McSwede are
smaller than fifty acres.

   WildWest draws the fifty-acre requirement from the Old
Growth Guidelines, which appear as Appendix 17 to the For-
est Plan. Ordinarily, such a document would not have the
force and effect of binding law. See Western Radio Servs. Co.,
Inc. v. Espy, 79 F.3d 896, 901 (9th Cir. 1996); Chrysler Corp.
v. Brown, 441 U.S. 281, 301 (1979) (holding a Forest Service
Manual and Handbook were not binding on the agency
because they did not constitute substantive law and were not
issued pursuant to the procedural requirements of the APA).

   [10] However, where an otherwise advisory document has
been clearly incorporated into a Forest Plan or other binding
document, its requirements become mandatory. See Swan
View Coal., Inc. v. Barbouletos, No. 07-35065, 2009 WL
118056, at *1 (9th Cir. Jan. 6, 2009) (noting Interagency Griz-
zly Bear Guidelines were incorporated into the Flathead For-
est Plan and treating such guidelines as binding); Res., Ltd. v.
Robertson, 35 F.3d 1300, 1304 (9th Cir. 1993) (finding a vio-
lation of Interagency Grizzly Bear Guidelines because project
approval was explicitly conditioned on compliance with the
guidelines). In this case, it appears that the Guidelines were
incorporated into the binding Forest Plan. The Forest Plan
states: “Specific Forest Guidelines exist and will be applied
for . . . Old growth habitat and dependent species (Appendix
17).”

   [11] However, even though the Old Growth Guidelines
were incorporated into the Forest Plan, the language at issue
here does not create a mandatory standard. We have repeat-
edly noted that “the presence of a few, isolated provisions cast
in mandatory language does not transform an otherwise sug-
gestive set of guidelines into binding agency regulations.”
Terbush v. United States, 516 F.3d 1125, 1139 n.7 (9th Cir.
2008) (quoting Sabow v. United States, 93 F.3d 1445, 1453
(9th Cir. 1996)); see Chamberlin v. Isen, 779 F.2d 522, 525
9410          WILDWEST INSTITUTE v. CASTANEDA
(9th Cir. 1985) (reviewing Manual of Patent Examining Pro-
cedures and concluding that while “[i]t is true that the MPEP
contains some mandatory language,” for the most part, “the
MPEP only suggests or authorizes procedures for patent
examiners to follow”).

  The Old Growth Guidelines state:

    [U]nits of 50-100 acres are the smallest acceptable
    size . . . . While units of a minimum of 50 acres may
    be acceptable in some circumstances, 50 acres
    should be the exception rather than the rule. Efforts
    should be made to provide old growth habitat in
    blocks of 100 acres or larger. If, due to past fires or
    management activities, the only remaining old
    growth blocks are less than 50 acres, they may still
    be useful habitat provided that several small blocks
    are clustered together or are surrounded by mature
    habitat.

   We cannot conclude that this language creates a mandatory
rule that strictly limits designation of old growth to blocks
larger than 50 acres. The section is cast in suggestive (i.e.,
“should” and “may”) rather than mandatory (e.g., “must” or
“only”) terms. See Sabow, 93 F.3d at 1452. It suggests how
old growth should be managed, not how it must be desig-
nated. As the district court correctly concluded, the Forest
Plan does not mandate stands of fifty acres or more; “rather,
such a practice is merely recommended when possible.” Wild-
west Inst., 462 F. Supp. 2d at 1161.

   Our review is confined to the question of whether the For-
est Service violated NFMA. If the guideline language under-
lying the plaintiff’s claim is merely advisory or aspirational,
the answer must be “no.” See Or. Natural Res. Council v.
Lowe, 109 F.3d 521, 527 (9th Cir. 1997) (holding Forest Ser-
vice did not violate NFMA in attaining only the minimum
levels of protection required by law, though “the Forest Ser-
               WILDWEST INSTITUTE v. CASTANEDA             9411
vice itself recommends that forest planning alternatives
should adopt management guidelines above the [mini-
mums]”). The language of Appendix 17 is not mandatory.
Moreover, Appendix 17 plainly contemplates that blocks of
less than fifty acres will be treated as relevant to forest man-
agement decisions. Therefore, regardless of whether the For-
est Service has or has not designated stands smaller than fifty
acres, it has not acted arbitrarily or capriciously.

C. Designation of Old Growth: Effective vs. Replace-
ment

   WildWest next challenges the Forest Service’s inclusion of
some replacement old growth in its analyses, arguing that
habitat which does not presently meet the needs of old-growth
species should not count toward the ten percent minimum.
WildWest does not refer to any specific project in this section
of its brief, but does in various other sections refer to the
levels of old growth habitat in each project area. We treat the
claim as properly raised with respect to all nine site-specific
projects.

   [12] The general requirements of the Forest Plan state only
that “10% of the Kootenai National Forest land base below
5,500 feet in elevation will be in an old-growth timber condi-
tion.” The Forest Plan does not address whether replacement
old growth may be included in the Forest Service’s calcula-
tion to attain the ten percent level. Therefore, the Forest Ser-
vice is not clearly precluded from designating effective old
growth or including effective old growth in its analyses.

   [13] Assuming the Forest plan leaves some ambiguity as to
whether replacement old growth should be included, we defer
to the Forest Service’s reasonable interpretation of the Forest
Plan’s requirements. Lands Council v. Powell (Lands Council
I), 395 F.3d 1019, 1034 (9th Cir. 2005); Idaho Sporting Cong.
v. Thomas, 137 F.3d 1146, 1154 (9th Cir. 1998) (deferring to
the Forest Service’s expertise in interpreting its Land Man-
9412           WILDWEST INSTITUTE v. CASTANEDA
agement Plan), overruled on other grounds by Lands Council
II, 537 F.3d at 997.

    The Forest Service’s interpretation of the ten percent stan-
dard is reasonable for two reasons. First, the Forest Plan FEIS
provides: “Long-term management, [as opposed to existing,
natural old-growth], includes recognition of existing old
growth, but also includes designation of future old growth
. . . .” (emphasis added). This language plainly indicates that
the Forest Service may include replacement old growth in its
analyses.

   Second, as the district court highlighted in a prior related
case, the KNF did not meet the ten percent standard based on
existing old growth alone at the time the Forest Plan was
adopted. Ecology Ctr., Inc. v. Castaneda, No. CV 02-200-M-
DWM, 2003 WL 25548017, at *4 (D. Mont. June 27, 2003).
Designation of areas not yet possessing all the characteristics
of old growth was necessary to meet the ten percent standard,
and to ensure careful preservation of these areas for the
future. It is therefore reasonable to interpret the Forest Plan as
permitting designation of replacement old growth to meet the
ten percent standard. Accordingly, the Forest Service did not
act in an arbitrary or capricious manner by including replace-
ment old growth in its statistics or analyses for purposes of
meeting the ten percent standard.

D.     Failure to Meet Ten Percent Standard

   The Forest Plan requires that at least ten percent of land
below 5500 feet in elevation be in old-growth condition.
Additionally, old growth must be “spread evenly through
most major drainages, and will represent the major forest
types in each drainage.” WildWest claims the KNF as a
whole, and the challenged project areas individually, fall
below the ten percent minimum. It also claims the Forest Ser-
vice failed to disclose the relevant data. WildWest has prop-
                 WILDWEST INSTITUTE v. CASTANEDA                    9413
erly raised this argument with respect to all nine site-specific
projects.

   The latest available data, which appears in the Monitoring
and Evaluation Report for Fiscal Years 2003-2004, indicates
that 10.5% of total KNF lands below 5500 feet are designated
effective old-growth. This alone would be sufficient to meet
the standard set forth in the Forest Plan. When replacement
old growth is included in the analysis, it reveals that 15.7%
of the forest is in old-growth condition. The number would be
higher still if undesignated old growth were included in this
analysis.2 The Monitoring and Evaluation Report concludes:
“the Forest is meeting its Forest Plan requirement for desig-
nating 10% [ ] old growth habitat well distributed across KNF
lands below 5,500 feet elevation.”

   [14] This conclusion is also true for the nine challenged
projects. Counting only designated old growth, the record
reveals that five of the nine site-specific projects—Pipestone,
South McSwede, West Troy, McSutten, and Lower Big Creek
—meet the ten percent standard based on effective old growth
alone. The other four—Bristow, Fortine, Alder Creek, and
Cow Creek—exceed the ten percent standard when both
effective and replacement old growth are included. Again, the
numbers are higher still when undesignated old growth areas
are considered. Because we conclude that designation of
replacement old growth is proper under the Forest Plan, then
all nine projects were in compliance with the ten percent stan-
dard as of the date of the project studies.

  The projects authorize no commercial harvesting of desig-
nated effective old growth, and only limited amounts of har-
vesting in undesignated areas. Completion of these projects
would therefore have no impact on whether the KNF as a
  2
   WildWest does not apparently challenge the inclusion of undesignated
areas in the Forest Service’s statistics, though under the Forest Plan the
Forest Service may properly include them.
9414            WILDWEST INSTITUTE v. CASTANEDA
whole meets the ten percent standard. Therefore, approval of
these projects was lawful under the Forest Plan.

E.     Population Viability

   [15] WildWest next argues the KNF has insufficient habitat
to support a viable population of pileated woodpeckers, the
MIS for old growth habitat. The Forest Plan requires the For-
est Service to measure “[p]opulation levels of old-growth
dependent species” in order to “[m]aintain viable popula-
tion[s] of old-growth dependent species.” A viable population
is defined as a one that is at least forty percent of the potential
population for any given species in the KNF.

   [16] WildWest first claims the minimum viable population
for the pileated woodpecker in the KNF is 554 breeding pairs,
which represents forty percent of the 1384 pairs the KNF was
historically able to support. However, as WildWest notes in
its brief, the KNF was historically able to support a range of
335 to 1384 pairs. WildWest does not explain why the stan-
dard must be forty percent of the range’s upper limit. The For-
est Service calculated the viability threshold as a range of 335
to 554 breeding pairs, based on historical data. The lower
bound of 335 pairs is reasonable. The potential population
was at some time reduced to 335 pairs due to natural distur-
bances. From that nadir, the estimated population has since
grown larger. Therefore, the population was necessarily via-
ble at 335 pairs. The upper bound of 554 pairs represents forty
percent of the KNF’s historical maximum potential, as sug-
gested by the Forest Plan. Therefore, this range of 335 to 554
pairs is a reasonable interpretation of the Forest Plan’s provi-
sions for maintaining species viability. The KNF is currently
home to 425 breeding pairs of woodpeckers, well within the
permissible range, and the Forest Service’s determinations in
this respect were not arbitrary or capricious.

 WildWest also claims seven of the nine challenged projects
—McSutten, Fortine, West Troy, Lower Big Creek, Bristow,
               WILDWEST INSTITUTE v. CASTANEDA              9415
Alder Creek, and Cow Creek—will adversely affect the
KNF’s ability to support a viable number of pileated wood-
peckers. Its main argument is that any alteration to the old
growth habitat resulting from the approved projects will
impair the viability of the pileated woodpecker. We have
already rejected this general proposition. As we noted in
Lands Council II, “[a] habitat disturbance does not necessarily
mean that a species’ viability will be threatened.” 537 F.3d at
997.

   [17] Though they may have adverse effects on the wood-
pecker, there is no indication the nine challenged projects
would force the woodpecker population below thresholds of
viability. The facts in this case are similar to those in Lands
Council II. There, the record included studies “describing the
quality and quantity of habitat necessary to sustain the viabili-
ty” of the MIS. Id. The Forest Service had analyzed the suit-
ability of the habitat for the MIS before and after the proposed
project. Id. We concluded, “[t]hat a proposed project involves
some disturbance to the forest does not prohibit the Forest
Service from assuming that maintaining a sufficient amount
of suitable habitat will maintain a species’ viability.” Id.

   The result is the same here. The Forest Service has care-
fully described both the quantity and quality of habitat that is
necessary to sustain a viable population of the pileated wood-
pecker and has explained its methodology for measuring old-
growth habitat. See Native Ecosystems Council v. U.S. Forest
Serv., 428 F.3d 1233, 1250 (9th Cir. 2005). It conducted
extensive analysis for each project area, considering the
effects on indicator species, such as impact on nesting and
feeding habitat. It concluded that although the nine projects
may affect old-growth species, they do not threaten species
viability. For eight of the nine projects, the EIS explicitly
addresses the likely effects on the pileated woodpecker and
concludes the project will not impair the bird’s viability. The
only project for which the EIS does not specifically address
the effects on the pileated woodpecker is the Pipestone proj-
9416            WILDWEST INSTITUTE v. CASTANEDA
ect. However, the Forest Service did engage in extensive anal-
ysis of the effects on three other old-growth dependent birds,
and concluded there would be no loss of viability. It also
found the project design criteria would “insure management
for sufficient snags and snag replacement trees to maintain
viable population of snag dependent species.” Snags are one
of the pileated woodpecker’s listed habitats. This is the sort
of scientific prediction to which we give great deference to
the agency. See Lands Council II, 537 F.3d at 993 (citations
omitted).

   Based on this extensive analysis, the Forest Service con-
cluded that the challenged projects would leave sufficient old
growth to support a viable population of pileated woodpeck-
ers. Therefore, the decision to approve the challenged projects
was not arbitrary or capricious.

F.     Use of Habitat Proxies

   WildWest next raises several challenges to the Forest Ser-
vice’s use of habitat proxies. Once again, WildWest fails to
cite to the record for any specific project in this section of its
brief. However, because it has elsewhere challenged measure-
ment of and compliance with the standards for old growth, we
treat this claim as properly raised with respect to all nine proj-
ects.

   Where data on the MIS is incomplete or difficult to collect,
the Forest Service monitors the habitat of the MIS, which is
mature and old growth forest in the case of the pileated wood-
pecker. By studying the result of a timber sale on the habitat
of the pileated woodpecker, the Forest Service attempts to
estimate its effects on all old growth species. See Idaho Sport-
ing Cong. v. Rittenhouse, 305 F.3d 957, 971-72 (9th Cir.
2002) (describing this approach).

  [18] WildWest apparently claims that both parts of the
measurement have failed—i.e., both the population target and
                WILDWEST INSTITUTE v. CASTANEDA                9417
the designation of old-growth habitat for the pileated wood-
pecker are improper. As discussed above, neither of these
claims has merit. To the extent that WildWest challenges the
proxy-on-proxy approach generally, the argument is fore-
closed by our case law. We have repeatedly approved “the
Forest Service’s use of the amount of suitable habitat for a
particular species as a proxy for the viability of that species.”
Lands Council II, 537 F.3d at 996 (finding “eminently reason-
able” the conclusion that the challenged project would main-
tain a viable MIS population because it would not decrease
MIS habitat in the short-term and would promote the long-
term viability of MIS habitat); id. at 996 n.10 (noting “[w]e
have also allowed the Forest Service to use habitat as a proxy
to measure a species’ population, and then to use that species’
population as a proxy for the population of other species
(proxy-on-proxy approach)”); Inland Empire, 88 F.3d at 761
(approving Forest Service’s “habitat as a proxy approach”).

   WildWest relies heavily on three cases in which manage-
ment decisions based on the proxy-on-proxy approach were
invalidated. See Earth Island Inst. v. U.S. Forest Serv., 442
F.3d 1147 (9th Cir. 2006), cert. denied, 549 U.S. 1278 (2007);
Lands Council I, 395 F.3d at 1036; Idaho Sporting Cong. v.
Rittenhouse, 305 F.3d at 970. Such reliance is misplaced. In
each of those cases, the Forest Service failed to accurately
identify and measure the relevant habitat. See Lands Council
II, 537 F.3d at 997-98 (“[W]hen the Forest Service decides,
in its expertise, that habitat is a reliable proxy for species’ via-
bility in a particular case, the Forest Service nevertheless must
both describe the quantity and quality of habitat that is neces-
sary to sustain the viability of the species in question and
explain its methodology for measuring this habitat.”). We
held that reliance on habitat proxies was invalid because the
essential data underlying the decision was flawed. For
instance, in Lands Council I, the Forest Service’s database, its
“main tool for old growth calculation,” contained data that
was fifteen years old, inaccurate, and insufficient on many
variables. 395 F.3d at 1036.
9418             WILDWEST INSTITUTE v. CASTANEDA
   No such defect exists here. WildWest does not challenge
the Forest Service’s identification of old growth as the wood-
pecker’s habitat or its measurement of old-growth habitat for
purposes of the proxy. As discussed above, the Forest Ser-
vice’s designations of old growth were proper, and it engaged
in extremely thorough analysis of habitat impact before
approving the projects. The record contains detailed data on
the location, condition, and amount of old growth habitat in
the affected areas. Therefore, the Forest Service’s use of the
proxy-on-proxy approach was not arbitrary or capricious.

G.     Use of Best Management Practices

   WildWest makes several allegations related to the Forest
Service’s management of watersheds and aquatic habitat in
the KNF.3 Though not listed in the Issues on Appeal, Wild-
West’s Opening Brief complains at length of the Forest Ser-
vice’s use of Best Management Practices (“BMPs”) to protect
fisheries. It claims BMPs have “clearly failed to adequately
protect and maintain riparian areas in acceptable condition” in
watersheds impacted by all nine of the challenged projects.
We understand WildWest’s argument to be that because
BMPs have proved inadequate to protect watersheds thus far,
it is arbitrary and capricious to use BMPs to evaluate and
approve the new site-specific projects.

   We have not specifically addressed whether use of BMPs
is a reasonable management strategy. Rather, we review
BMPs according to the same standard by which we review all
agency choices with respect to models, methodologies, and
  3
    WildWest fails to connect three of the four arguments to the challenged
site-specific projects, and we therefore do not address them. Additionally,
much of WildWest’s argument on these issues appears to conflate
NFMA’s substantive requirements with NEPA’s procedural requirement
that agencies conduct cumulative impact analyses. See 40 C.F.R. § 1508.7.
To the extent these arguments challenge the Forest Service’s consideration
and disclosure of the cumulative effects of long-term management deci-
sions, they are addressed below.
               WILDWEST INSTITUTE v. CASTANEDA              9419
weighing scientific evidence: their choices must be supported
by reasoned analysis. For instance, we noted in Environmen-
tal Protection Information Center v. United States Forest Ser-
vice, 451 F.3d 1005 (9th Cir. 2006), that references to detailed
BMPs supported the conclusion the Forest Service had taken
the requisite “hard look” at a project’s environmental conse-
quences. Id. at 1015-16; see also Res. Ltd., Inc. v. Robertson,
35 F.3d 1300, 1306 (9th Cir. 1993) (noting use of BMPs to
ensure maintenance of water quality in action challenging
general planning strategies). Additionally, we reviewed the
substance of BMPs in Blue Mountains Biodiversity Project v.
Blackwood, 161 F.3d 1208 (9th Cir. 1998). There, we found
that disclosure of mitigation measures was inadequate
because the Forest Service relied on BMPs developed for sig-
nificantly different circumstances from those existing in the
disputed project areas. Id. at 1214.

   [19] Here, the Forest Service reasonably used and relied on
BMPs. The record reveals the BMPs used in the KNF are
carefully considered and tailored to the projects for which
they are used. For instance, the Pipestone EIS, which contains
an extensive appendix of BMPs to be applied, recommends
specific practices and the results to be obtained by those prac-
tices. Unlike in Blue Mountains, the BMPs here were devel-
oped for the precise circumstances at hand. So long as BMPs
are supported by reasonable scientific assumptions, reason-
ably appropriate for the circumstances at hand, the Forest Ser-
vice is not acting in an arbitrary and capricious fashion in
relying on them.

   [20] Moreover, the Forest Service points to specific evi-
dence indicating implementation of BMPs has been quite suc-
cessful in improving some watersheds. WildWest has not
proven that the poor conditions of which they complain are a
direct result of the BMPs used in the site-specific project anal-
yses. Nor have they proven the poor conditions can be attri-
buted to BMPs generally, as opposed to historical practices,
other management practices, or assumptions. In light of this
9420           WILDWEST INSTITUTE v. CASTANEDA
evidence, the Forest Service did not act in an arbitrary and
capricious fashion in relying on BMPs in evaluating and
approving the challenged projects.

                      V.   NEPA Claims

A.     Failure to Consider and Disclose Cumulative Effects

   [21] WildWest next argues the Forest Service has failed to
adequately consider and disclose the cumulative effect on
water quality and fish resulting from “chronic failure” to
implement BMPs. NEPA requires the Forest Service to per-
form a cumulative impact analysis in approving projects.
Kern v. BLM, 284 F.3d 1062, 1075-76 (9th Cir. 2002). This
analysis requires the EIS to analyze the impact of a proposed
project in light of that project’s interaction with the effects of
past, current, and reasonably foreseeable future projects. 40
C.F.R. § 1508.7; see Lands Council I, 395 F.3d at 1027.

   WildWest complains the cumulative impact statements do
not contain discussion of prior projects on an individual basis.
“[T]he general rule under NEPA is that, in assessing cumula-
tive effects, the Environmental Impact Statement must give a
sufficiently detailed catalogue of past, present, and future
projects, and provide adequate analysis about how these proj-
ects, and differences between the projects, are thought to have
impacted the environment.” Lands Council I, 395 F.3d at
1028. In Lands Council I, we found an EIS insufficient
because “the prior harvests from different projects were not
separately discussed, neither as to their method of harvest, nor
as to the consequences of each.” Id. We have repeatedly held
that general statements about prior projects affecting environ-
mental conditions are insufficient; “quantified or detailed
data” about the effects of specific projects is necessary. Or.
Natural Res. Council Fund v. Brong, 492 F.3d 1120, 1134
(9th Cir. 2007); see also Klamath-Siskiyou Wildlands Ctr. v.
BLM, 387 F.3d 989, 993 (9th Cir. 2004).
               WILDWEST INSTITUTE v. CASTANEDA              9421
   [22] However, in League of Wilderness Defenders—Blue
Mountains Biodiversity Project v. United States Forest Ser-
vice, 549 F.3d 1211 (9th Cir. 2008), we provided two impor-
tant clarifications of this standard. First, we held that the
Forest Service “may aggregate its cumulative effects analysis
pursuant to 40 C.F.R. § 1508.7,” the regulation defining “cu-
mulative impact.” Id. at 1218; see, e.g., WildWest Inst. v. Bull,
547 F.3d 1162, 1173 (9th Cir. 2008) (holding Forest Service’s
analysis of cumulative impacts of past timber harvests and
other historical events satisfied “hard look” standard). Sec-
ond, we noted that Lands Council I “merely reaffirms the gen-
eral rule that NEPA requires adequate cataloguing of relevant
past projects in the area.” Id. (internal quotation marks omit-
ted). The Forest Service need not catalogue events that are not
“truly significant to the action in question.” See id.; 40 C.F.R.
§ 1500.1(b); NW Envt’l Advocates v. Nat’l Marine Fisheries
Serv., 460 F.3d 1125, 1140 (9th Cir. 2006) (noting Lands
Council I required a detailed catalogue of projects in order to
“inform analysis,” and concluding that cataloguing is not
required where other projects would have no related effects).
We reiterate that an aggregated cumulative effects analysis
that includes relevant past projects is sufficient.

   [23] The Forest Service met this standard here. Generally,
the Forest Service explained in each EIS what the effects of
the project would be, including the existing condition of each
area along several variables. The Pipestone EIS explicitly
notes there have been no previous timber harvests in this area,
and there will therefore be no cumulative impacts. Although
the cumulative effects section of the West Troy EIS merely
refers generally to “past and proposed activities,” without list-
ing details about those activities, other parts of the EIS give
extensive history about past actions in the area, dating all the
way back to the early 1900s. Bristow’s EIS provides data on
the cumulative effects with other pending proposals and miti-
gation in areas with previous harvests. The South McSwede
EIS discusses past management practices and specific details
of planned projects. Lower Big Creek’s EIS refers to a table
9422           WILDWEST INSTITUTE v. CASTANEDA
of Current and Reasonably Foreseeable Actions, and states
past actions were considered in the Existing Conditions sec-
tion; it also notes two related plans and concludes there would
be no cumulative effects. The McSutten EIS concludes there
would be no cumulative effects from past actions or when
coupled with current and reasonably foreseeable actions. The
Fortine EIS contains a detailed aggregated discussion of exist-
ing conditions.

   We conclude the Forest Service adequately considered and
disclosed the cumulative effects for purposes of NEPA. The
record includes extensive evidence that the Forest Service
considered the relevant prior and related actions and took the
requisite hard look before approving the challenged projects.

B.     Failure to Meaningfully Disclose Old Growth Data

   WildWest next contends the data upon which the Forest
Services bases its conclusions about the locations and distri-
bution of old-growth habitat is inaccessible. It claims that
“[i]n order to be verifiable (replicable) methodology, the
underlying ‘hard data’ for each polygon should reveal how
that polygon meets the relevant old-growth criteria for the
particular habitat type.” The Forest Service has claimed there
is no more user-friendly way to format the data.

   [24] NEPA requires that the Forest Service disclose the
hard data supporting its expert opinions to facilitate the pub-
lic’s ability to challenge agency action. See Idaho Sporting
Cong. v. Thomas, 137 F.3d at 1150, overruled on other
grounds by Lands Council II, 537 F.3d at 997. We defer to an
agency’s choice of format for scientific data. See League of
Wilderness Defenders—Blue Mountains, 549 F.3d at 1218 (“It
is not for this court to tell the Forest Service what specific evi-
dence to include, nor how specifically to present it.”). Wild-
West does not contend the data is actually unavailable, and
the format of the data has not apparently impaired Wild-
West’s ability to bring legal challenges. Therefore, the Forest
               WILDWEST INSTITUTE v. CASTANEDA             9423
Service has fulfilled its obligations under Idaho Sporting Con-
gress.

C.   Failure to Disclose Inadequacy of Old-Growth Habi-
     tat

   Finally, WildWest argues that the Forest Service violated
NEPA by failing to disclose in NEPA documents that the
KNF no longer has adequate habitat to support a viable popu-
lation of pileated woodpeckers. This is a variation of its argu-
ment that the Forest Service failed to disclose and respond to
the Lesica study, which concluded a higher level of old
growth existed prior to European settlement.

   [25] Both formulations of this argument fail. As discussed
above, the Forest Service has provided a rational basis for its
choice of a ten percent old growth minimum. Moreover, an
agency need not respond to every single scientific study or
comment. See Lands Council II, 537 F.3d at 1001-02. Wild-
West claims that Center for Biological Diversity v. United
States Forest Service, 349 F.3d 1157 (9th Cir. 2003), requires
the Forest Service to disclose and respond to the Lesica study
because the evidence “directly challenge[d] the scientific
basis upon which the Final EIS rest[ed].” Id. at 1167. As dis-
cussed above, however, the Lesica study did not “directly
challenge” the Forest Service’s conclusion that ten percent old
growth was sufficient to sustain viable populations of old-
growth species. The record reveals the Forest Service took the
requisite hard look at and disclosed the relevant available
information in setting the ten percent standard.

                       VI.   Concusion

   For the reasons explained above, we conclude that the For-
est Service complied with the substantive requirements of
NFMA and the Forest Plan. The Forest Service also took the
requisite “hard look” at the environmental effects of the proj-
9424         WILDWEST INSTITUTE v. CASTANEDA
ects before approving them. The district court properly
entered summary judgment in favor of the Forest Service.

  AFFIRMED.
