                    FOR PUBLICATION

   UNITED STATES COURT OF APPEALS
        FOR THE NINTH CIRCUIT


 BARK; CASCADIA WILDLANDS;                       No. 19-35665
 OREGON WILD,
              Plaintiffs-Appellants,               D.C. No.
                                                3:18-cv-01645-
                     v.                              MO

 UNITED STATES FOREST SERVICE, a
 federal agency,                                 ORDER AND
                 Defendant-Appellee,              OPINION

 HIGH CASCADE, INC.,
     Intervenor-Defendant-Appellee.

        Appeal from the United States District Court
                 for the District of Oregon
       Michael W. Mosman, District Judge, Presiding

         Argued and Submitted December 10, 2019
                   Seattle, Washington

                          Filed May 4, 2020

        Before: Susan P. Graber, Marsha S. Berzon,
        and Stephen A. Higginson, * Circuit Judges.


   *
      Stephen A. Higginson, United States Circuit Judge for the U.S.
Court of Appeals for the Fifth Circuit, sitting by designation.
2                         BARK V. USFS

                           Order;
                 Opinion by Judge Higginson;
                 Concurrence by Judge Graber


                          SUMMARY **


                      Environmental Law

    The panel granted appellants’ request to publish the
unpublished Memorandum Disposition with modifications;
and reversed the district court’s summary judgment in favor
of the U.S. Forest Service in an action alleging violations of
the National Environmental Policy Act and National Forest
Management Act.

   The Crystal Clear Restoration (“CCR”) Project is a forest
management effort and timber sale affecting 11,742 acres in
Mt. Hood National Forest.

    The panel held that the Forest Service’s determination
that the CCR Project did not require an Environmental
Impact Statement (“EIS”) was arbitrary and capricious for
two independent reasons. First, the effects of the Project
were highly controversial and uncertain, thus mandating the
creation of an EIS. See 40 C.F.R. § 1508.27(b)(4) & (5).
Second, the Forest Service failed to identify and
meaningfully analyze the cumulative impacts of the Project.




    **
       This summary constitutes no part of the opinion of the court. It
has been prepared by court staff for the convenience of the reader.
                      BARK V. USFS                         3

    Because an EIS was required, and because the findings
in the EIS could prompt the Forest Service to change the
scope of the Project or the methods it planned to use, the
panel did not reach the appellants’ other claims. The panel
remanded to the Forest Service for further proceedings.

    Judge Graber concurred in full in the judgment and in all
but section III-B of the majority opinion. She agrees that an
EIS was required, but would not reach whether the
environmental assessments’ discussion of cumulative
impacts also was arbitrary and capricious.


                        COUNSEL

Brenna Bell (argued), Portland, Oregon; Nick Cady, Eugene,
Oregon; for Plaintiffs-Appellants.

Jeffrey S. Beelaert (argued), Shaun M. Pettigrew, and
Krystal-Rose Perez, Attorneys; Eric Grant, Deputy Assistant
Attorney General; Jeffrey Bossert Clark, Assistant Attorney
General; Environment and Natural Resources Division,
United States Department of Justice, Washington, D.C.;
Stephen A. Vaden, General Counsel; Val J. McLam Black,
Senior Counsel, United States Department of Agriculture,
Washington, D.C.; for Defendant-Appellee.

Lawson E. Fite (argued), and Sara Ghafouri, American
Forest Resource Council, Portland, Oregon, for Intervenor-
Defendant-Appellee.
4                      BARK V. USFS

                          ORDER

    Appellants’ request to publish the unpublished
Memorandum disposition, Docket No. 37, is GRANTED.
The Memorandum disposition filed April 3, 2020, is
redesignated as an authored Opinion by Judge Higginson,
with modifications. The time for filing a petition for
rehearing and petition for rehearing en banc shall start anew
as of the filed date of this Opinion.



                         OPINION

HIGGINSON, Circuit Judge:

    Appellants Bark, Cascadia Wildlands, and Oregon Wild
timely appeal the district court’s summary judgment in favor
of Appellees, the United States Forest Service (USFS) and
High Cascade, for claimed violations of the National
Environmental Policy Act (NEPA) and the National Forest
Management Act (NFMA). We hold that the USFS’s
determination that the Crystal Clear Restoration (CCR)
Project did not require an Environmental Impact Statement
(EIS) was arbitrary and capricious and so reverse. We do not
reach the NFMA claims.

                              I.

    The CCR Project is a forest management effort and
timber sale affecting 11,742 acres in Mt. Hood National
Forest. The Project area is partly a moist “transition”
climate, and partly a dry “eastside” climate. According to the
USFS, forest stands in the area tend to be overstocked as a
result of past management practices. When trees are closer
together, they are more susceptible to insects and disease and
                        BARK V. USFS                          5

to high-intensity wildfires. The USFS undertook the CCR
Project in order to “provide forest products from specific
locations within the planning area where there is a need to
improve stand conditions, reduce the risk of high-intensity
wildfires, and promote safe fire suppression activities.” The
USFS plans to achieve these goals in part using a technique
called “variable density thinning.” This process gives the
agency flexibility in choosing which trees to cut, thereby
allowing the USFS to create variation within an area of forest
so that the stands “mimic more natural structural stand
diversity.” The USFS plans to leave an average canopy cover
of 35–60%, with a minimum of 30% where the forest is more
than 20 years old.

    “NEPA imposes procedural requirements designed to
force agencies to take a ‘hard look’ at environmental
consequences” of their proposed actions. League of
Wilderness Defs./Blue Mountains Biodiversity Project v.
Connaughton, 752 F.3d 755, 763 (9th Cir. 2014) (internal
quotation marks omitted). Agencies must prepare an EIS for
federal actions that will “significantly affect[] the quality of
the human environment.” 42 U.S.C. § 4332(2)(C). To
determine whether a proposed action will have a significant
effect on the quality of the human environment, agencies
must prepare an Environmental Assessment (EA) that
“[b]riefly provide[s] sufficient evidence and analysis for
determining whether to prepare an environmental impact
statement or a finding of no significant impact.” 40 C.F.R.
§ 1508.9(a)(1). An EIS is required when this process raises
“substantial questions” about whether an agency action will
have a significant effect. Blue Mountains Biodiversity
Project v. Blackwood, 161 F.3d 1208, 1212 (9th Cir. 1998);
see also Native Ecosystems Council v. U.S. Forest Serv.,
428 F.3d 1233, 1238–39 (9th Cir. 2005). “If the agency
concludes in the EA that there is no significant effect from
6                      BARK V. USFS

the proposed project, the federal agency may issue a finding
of no significant impact (‘FONSI’) in lieu of preparing an
EIS.” Native Ecosystems Council, 428 F.3d at 1239 (citing
40 C.F.R. § 1508.9(a)(1); id. § 1508.13).

  After conducting an EA, the USFS determined that the
CCR Project had no significant effects. It therefore issued a
FONSI and did not prepare an EIS.

    Appellants filed a complaint against the USFS bringing
claims under NEPA and the NFMA. The NEPA claim
alleged that the USFS did not undertake a proper analysis of
the environmental impacts of the Project or of alternatives to
the Project. The NFMA claim alleged that the USFS failed
to comply with two forest plans and other guidance
documents governing the Project area as required by the
NFMA. The district court granted summary judgment to
Appellees on all claims. Appellants timely appealed.

                             II.

    We review the district court’s grant of summary
judgment de novo. Ctr. for Biological Diversity v. Ilano, 928
F.3d 774, 779 (9th Cir. 2019). The Administrative Procedure
Act (APA), 5 U.S.C. § 706(2)(A), provides the governing
standard for courts reviewing an agency’s compliance with
NEPA and the NFMA. Native Ecosystems Council, 428 F.3d
at 1238. Under the APA, we may overturn an agency’s
conclusions when they are “arbitrary, capricious, an abuse of
discretion, or otherwise not in accordance with law.”
5 U.S.C. § 706(2)(A). “An agency action is arbitrary and
capricious if the agency has: relied on factors which
Congress has not intended it to consider, entirely failed to
consider an important aspect of the problem, offered an
explanation for its decision that runs counter to the evidence
before the agency, or is so implausible that it could not be
                        BARK V. USFS                           7

ascribed to a difference in view or the product of agency
expertise.” WildEarth Guardians v. U.S. E.P.A., 759 F.3d
1064, 1069–70 (9th Cir. 2014) (quoting Ctr. for Biological
Diversity v. U.S. Bureau of Land Mgmt., 698 F.3d 1101,
1109 (9th Cir. 2012)). An agency’s factual determinations
“must be supported by substantial evidence.” Connaughton,
752 F.3d at 759.

    In reviewing an agency’s finding that a project has no
significant effects, courts must determine whether the
agency has met NEPA’s hard look requirement, “based [its
decision] on a consideration of the relevant factors, and
provided a convincing statement of reasons to explain why a
project’s impacts are insignificant.” In Def. of Animals v.
U.S. Dep’t of Interior, 751 F.3d 1054, 1068 (9th Cir. 2014)
(alteration in original) (quoting Envtl. Prot. Info. Ctr. v. U.S.
Forest Serv. (EPIC), 451 F.3d 1005, 1009 (9th Cir. 2006)).
The term “significant” includes considerations of both the
context and the intensity of the possible effects. 40 C.F.R.
§ 1508.27. “Context simply delimits the scope of the
agency’s action, including the interests affected.” In Def. of
Animals, 751 F.3d at 1068 (quoting Nat’l Parks &
Conservation Ass’n v. Babbitt, 241 F.3d 722, 731 (9th Cir.
2001), abrogated in part on other grounds by Monsanto Co.
v. Geertson Seed Farms, 561 U.S. 139, 157 (2010)).
Consideration of context involves analysis “in several
contexts such as society as a whole (human, national), the
affected region, the affected interests, and the locality.”
40 C.F.R. § 1508.27(a). “[I]n the case of a site-specific
action, significance . . . usually depend[s] upon the effects in
the locale rather than in the world as a whole.” Id.

   Consideration of intensity “refers to the severity of
impact.” Id. § 1508.27(b). NEPA regulations list ten non-
exhaustive factors that inform an agency’s intensity
8                      BARK V. USFS

determination, including “[t]he degree to which the effects
on the quality of the human environment are likely to be
highly controversial,” id. § 1508.27(b)(4), “[t]he degree to
which the possible effects on the human environment are
highly uncertain or involve unique or unknown risks,” id.
§ 1508.27(b)(5), and “[w]hether the action is related to other
actions with individually insignificant but cumulatively
significant impacts,” id. § 1508.27(b)(7). The regulations
explain that “[s]ignificance exists if it is reasonable to
anticipate a cumulatively significant impact on the
environment,” and “cannot be avoided by . . . breaking [an
action] down into small component parts.” Id. “When
substantial questions are raised as to whether a proposed
project ‘may cause significant degradation of some human
environmental factor,’ an EIS is required.” In Def. of
Animals, 751 F.3d at 1068.

                             III.

   The USFS’s decision not to prepare an EIS was arbitrary
and capricious for two independent reasons.

                              A.

    First, the effects of the Project are highly controversial
and uncertain, thus mandating the creation of an EIS. See
40 C.F.R. § 1508.27(b)(4) & (5) (listing relevant factors for
whether an EIS is required, including if the project’s effects
are “highly controversial” and “highly uncertain”). The
stated primary purpose of the CCR Project is to reduce the
risk of wildfires and promote safe fire-suppression activities,
but Appellants identify considerable scientific evidence
showing that variable density thinning will not achieve this
purpose. Considering both context and intensity, as required
by 40 C.F.R. § 1508.27, this evidence raises substantial
questions about the Project’s environmental impact, and an
                       BARK V. USFS                          9

EIS is required. See, e.g., Blackwood, 161 F.3d at 1212;
Native Ecosystems Council, 428 F.3d at 1238–39.

    “A project is ‘highly controversial’ if there is a
‘substantial dispute [about] the size, nature, or effect of the
major Federal action rather than the existence of opposition
to a use.’” Native Ecosystems Council, 428 F.3d at 1240
(alteration in original) (quoting Blackwood, 161 F.3d
at 1212). “A substantial dispute exists when evidence . . .
casts serious doubt upon the reasonableness of an agency’s
conclusions.” In Def. of Animals, 751 F.3d at 1069 (quoting
Babbitt, 241 F.3d at 736). “[M]ere opposition alone is
insufficient to support a finding of controversy.” WildEarth
Guardians v. Provencio, 923 F.3d 655, 673 (9th Cir. 2019).

    The EA explained that the CCR Project will use
“variable density thinning” to address wildfire concerns. “In
variable density thinning, selected trees of all sizes . . .
would be removed.” This process would assertedly make the
treated areas “more resilient to perturbations such as . . .
large-scale high-intensity fire occurrence because of the
reductions in total stand density.” Variable density thinning
will occur in the entire Project area.

    Substantial expert opinion presented by the Appellants
during the administrative process disputes the USFS’s
conclusion that thinning is helpful for fire suppression and
safety. For example, Oregon Wild pointed out in its EA
comments that “[f]uel treatments have a modest effect on
fire behavior, and could even make fire worse instead of
better.” It averred that removing mature trees is especially
likely to have a net negative effect on fire suppression.
Importantly, the organization pointed to expert studies and
research reviews that support this assertion.
10                      BARK V. USFS

    Bark also raised this issue: “It is becoming more and
more commonly accepted that reducing fuels does not
consistently prevent large forest fires, and seldom
significantly reduces the outcome of these large fires,” citing
an article from Forest Ecology and Management. Bark also
directed the USFS to a recent study published in The Open
Forest Science Journal, which concluded that fuel
treatments are unlikely to reduce fire severity and
consequent impacts, because often the treated area is not
affected by fire before the fuels return to normal levels. Bark
further noted that, while “Bark discussed [during the scoping
process] the studies that have found that fuel reduction may
actually exacerbate fire severity in some cases as such
projects leave behind combustible slash, open the forest
canopy to create more ground-level biomass, and increase
solar radiation which dries out the understory[,] [t]he EA did
not discuss this information.”

    Oregon Wild also pointed out in its EA comments that
fuel reduction does not necessarily suppress fire. Indeed, it
asserted that “[s]ome fuel can actually help reduce fire, such
as deciduous hardwoods that act as heat sinks (under some
conditions), and dense canopy fuels that keep the forest cool
and moist and help suppress the growth of surface and ladder
fuels . . . .” Oregon Wild cited more than ten expert sources
supporting this view. Importantly, even the Fuels Specialist
Report produced by the USFS itself noted that “reducing
canopy cover can also have the effect of increasing [a fire’s
rate of spread] by allowing solar radiation to dry surface
fuels, allowing finer fuels to grow on . . . the forest floor, and
reducing the impact of sheltering from wind the canopy
provides.”

   The effects analysis in the EA did not engage with the
considerable contrary scientific and expert opinion; it
                        BARK V. USFS                           11

instead drew general conclusions such as that “[t]here are no
negative effects to fuels from the Proposed Action
treatments.” Appellants thus have shown a substantial
dispute about the effect of variable density thinning on fire
suppression. Although it is not our role to assess the merits
of whether variable density thinning is indeed effective in
the project area to prevent fires, or to take sides in a battle of
the experts, see Greenpeace Action v. Franklin, 14 F.3d
1324, 1333 (9th Cir. 1992), NEPA requires agencies to
consider all important aspects of a problem. See WildEarth
Guardians, 759 F.3d at 1069–70. Throughout the USFS’s
investigative process, Appellants pointed to numerous
expert sources concluding that thinning activities do not
improve fire outcomes. In its responses to these comments
and in its finding of no significant impact, the USFS
reiterated its conclusions about vegetation management but
did not engage with the substantial body of research cited by
Appellants. This dispute is of substantial consequence
because variable density thinning is planned in the entire
Project area, and fire management is a crucial issue that has
wide-ranging ecological impacts and affects human life.
When one factor alone raises “substantial questions” about
whether an agency action will have a significant
environmental effect, an EIS is warranted. See Ocean
Advocates v. U.S. Army Corps of Eng’rs, 402 F.3d 846, 865
(9th Cir. 2005) (“We have held that one of [the NEPA
intensity] factors may be sufficient to require preparation of
an EIS in appropriate circumstances.”). Thus, the USFS’s
decision not to prepare an EIS was arbitrary and capricious.
See Blackwood, 161 F.3d at 1213 (holding that conflicting
evidence on the effects of ecological intervention in post-fire
landscapes made a proposed project highly uncertain, thus
requiring an EIS).
12                     BARK V. USFS

                             B.

    The USFS also failed to identify and meaningfully
analyze the cumulative impacts of the Project. “Cumulative
impact is the impact on the environment which results from
the incremental impact of the action when added to other
past, present, and reasonably foreseeable future actions
regardless of what agency . . . undertakes such other
actions.” 40 C.F.R. § 1508.7. “Cumulative impacts can
result from individually minor but collectively significant
actions taking place over a period of time.” Id. “[I]n
considering cumulative impact, an agency must provide
‘some quantified or detailed information; . . . [g]eneral
statements about possible effects and some risk do not
constitute a hard look absent a justification regarding why
more definitive information could not be provided.’” Ocean
Advocates, 402 F.3d at 868 (alterations in original) (quoting
Neighbors of Cuddy Mountain v. U.S. Forest Serv., 137 F.3d
1372, 1379–80 (9th Cir. 1998)). “This cumulative analysis
‘must be more than perfunctory; it must provide a useful
analysis of the cumulative impacts of past, present, and
future projects.’” Id. (quoting Kern v. U.S. Bureau of Land
Mgmt., 284 F.3d 1062, 1075 (9th Cir. 2002)) (internal
quotation marks omitted). We have held that cumulative
impact analyses were insufficient when they “discusse[d]
only the direct effects of the project at issue on [a small
area]” and merely “contemplated” other projects but had “no
quantified assessment” of their combined impacts. Klamath-
Siskiyou Wildlands Ctr. v. Bureau of Land Mgmt., 387 F.3d
989, 994 (9th Cir. 2004).

   The EA ostensibly analyzed the cumulative effects of the
CCR Project, and included a table of other projects that were
“considered in the cumulative effects analyses.” The
cumulative impact analysis is insufficient because there is no
                       BARK V. USFS                         13

meaningful analysis of any of the identified projects. The
table gave no information about any of the projects listed; it
merely named them. The section of the EA actually
analyzing the cumulative effects on vegetation resources did
not refer to any of these other projects. Nor are there any
specific factual findings that would allow for informed
decision-making. The EA simply concluded that “there are
no direct or indirect effects that would cumulate from other
projects due to the minimal amount of connectivity with past
treatments” and that the Project “would have a beneficial
effect on the stands by moving them toward a more resilient
condition that would allow fire to play a vital role in
maintaining stand health, composition and structure.” These
are the kind of conclusory statements, based on “vague and
uncertain analysis,” that are insufficient to satisfy NEPA’s
requirements. Ocean Advocates, 402 F.3d at 869.

    The EA also mentioned the possibility of cumulative
effects in sections on other specific sub-topics such as fuels
management, transportation resources, and soil productivity.
These sections similarly relied on conclusory assertions that
the Project has “no cumulative effects.” When the EA did
acknowledge the possibility of the Project’s impact, such as
in the section that analyzed the Project’s effects on spotted
owls, it noted only that “[t]imber harvest on federal, tribal,
and private land, and utility corridor operations have reduced
the amount of suitable habitat . . . on the landscape and could
continue to do so in the future,” without attempting to
quantify the cumulative loss or naming other projects. Yet
there were other relevant timber projects to discuss.
Appellants pointed out at least three other recent or future
timber projects in their comments responding to the EA, but
the relevant section of the document limited its analysis to
only the Project area and a 1.2-mile buffer surrounding it.
Such a small buffer zone fails to distinguish the EA’s
14                      BARK V. USFS

cumulative impact analysis from an analysis of the direct
effects of the Project. See Klamath-Siskiyou Wildlands Ctr.,
387 F.3d. at 997 (assessing cumulative effects at the critical
habitat unit scale). The USFS’s failure to engage with the
other projects identified by Appellants leaves open the
possibility that several small forest management actions will
together result in a loss of suitable owl habitat. Preventing or
adequately mitigating this potential loss is the fundamental
purpose of NEPA’s requirement that agencies analyze
cumulative impacts, and we have no basis in the record to
assess whether the USFS has taken the necessary steps to
consider this possibility.

    Overall, there is nothing in the EA that could constitute
“quantified or detailed information” about the cumulative
effects of the Project. Ocean Advocates, 402 F.3d at 868
(internal quotation marks omitted). The USFS’s analysis
creates substantial questions about whether the action will
have a cumulatively significant environmental impact.
Therefore, this factor also requires the USFS to conduct an
EIS. See 40 C.F.R. § 1508.27(b)(7).

                              IV.

    Because an EIS is required, and because the findings in
the EIS could prompt the USFS to change the scope of the
Project or the methods it plans to use, we do not reach the
Appellants’ other claims. We reverse the district court’s
judgment and remand to the district court with instructions
to remand to the USFS for further proceedings consistent
with this opinion.

     REVERSED and REMANDED.
                       BARK V. USFS                         15

GRABER, Circuit Judge, concurring:

   I concur in full in the judgment and in all but section III-
B of the majority opinion. The project’s proposed
methodology of variable density thinning is both highly
controversial and highly uncertain, so an environmental
impact statement is required. I would not reach whether the
environmental assessment’s discussion of cumulative
impacts also was arbitrary and capricious.
