The United States appeals the district court’s dismissal of an information filed against defendants Michael D. Linick and Henry G. Bailey, III (collectively “Defendants”). The information charged Defendants with the use of the Apache-Sit-greaves National Forest without a permit in violation of 16 U.S.C. § 551 and related Forest Service regulations. In dismissing the information, the district court ruled that the language of 36 C.F.R. § 251.56(a)(2)(vii) was overbroad, which rendered unconstitutional the Forest Service’s regulatory scheme for the noncommercial group use of National Forest System land. We have jurisdiction pursuant to 28 U.S.C. § 1291. We AFFIRM in part and REVERSE in part.
I.
Defendants are members of the Rainbow Family, a loosely structured group of people who gather at least once a year on National Forest System land to pray for peace and discuss political and environmental issues. In June 1998, the Rainbow Family held a gathering in the Apache-Sitgreaves National Forest without first obtaining a noncommercial group use permit for the event. When Defendants participated in the gathering, the Forest Service cited them for violating 16 U.S.C. § 551 and 36 C.F.R. § 261.10(k) — namely unauthorized special use of National Forest System land. 2
Defendants moved the district court to dismiss the information, arguing that the Forest Service’s regulatory scheme for the noncommercial group use of National Forest System land was unconstitutional on its face. Among other things, they argued that 36 C.F.R. § 251.56(a)(2)(vii), which allows the Forest Service to attach any terms and conditions that protect the public interest to any special-use permit granted by the Forest System, contained overbroad language that would allow the Forest Service to restrict the use of public land by applicants who seek to express a disfavored view. 3 The district court grant *541 ed Defendants’ motion to dismiss, ruling that 36 C.F.R. § 251.56(a)(2)(vii) gave Forest Service officers impermissibly broad discretion in violation of the First Amendment.
It is undisputed that the Rainbow Family’s June 1998 gathering was a noncommercial group use of National Forest System land within the meaning of 36 C.F.R. § 251.51 and that such use was therefore subject to the regulatory scheme. 4 Today we decide the constitutionality of that scheme.
II.
We review de novo the district court’s grant of Defendants’ motion to dismiss because the dismissal involved only questions of law.
See Roulette v. City of Seattle,
In
Lakewood,
the Supreme Court allowed a facial challenge to the constitutionality of a city ordinance which vested the mayor with the authority to grant permits to place newsraeks on public property. That ordinance allowed the mayor to attach to the permit any “terms and conditions deemed necessary and reasonable.”
Id.
at 754,
36 C.F.R. § 251.56(a)(2)(vii) bears striking similarities to the “terms and conditions” provision of the Lakewood ordinance. It too contains language that effectively permits a governmental authority—in this case the Forest Service— to attach any “terms and conditions” to a permit. Specifically, 36 C.F.R. § 251.56(a)(2)(vii) states that a special use permit may contain such “terms and conditions as the authorized officer deems necessary to ... otherwise protect the public interest.” On its face, this language vests the Forest Service with the power to restrict the use of public land for an unlimited number of reasons so *542 long as it can claim that the restriction serves the public’s interest.
Although 36 C.F.R. § 251.54(h)(1) prohibits the Forest Service from summarily denying a permit on the basis of the public interest, the Forest Service’s broad discretion to attach terms and conditions to a permit can be abused in a manner that could limit the use of public land by parties who hold political views that are disfavored by the Forest Service. In the same way that the
Lakewood
mayor could have attached conditions to newsrack permits so as to relegate certain racks to effectively inaccessible locations,
see Lakewood,
Despite the government’s assertion to the contrary,
Ward v. Rock Against Racism,
III.
The fact that 36 C.F.R. § 251.56(a)(2)(vii) is facially invalid, however, does not end our inquiry. In evaluating the constitutionality of a regulatory scheme, we should “presume any narrowing construction ... to which the law is ‘fairly susceptible.’ ”
Lakewood,
In the instant case, the Forest Service recently promulgated an interpretive rule to clarify the scope of 36 C.F.R. § 251.56. See 64 Fed.Reg. 48,959 (1999). The interpretive rule states in relevant part:
The imposition of terms and conditions in noncommercial group use permits is limited to those designed to further the three public interests identified by the Forest Service in promulgating the noncommercial group use rule, i.e., the need to address concerns of public health and safety, to minimize damage to National Forest System resources, and to allocate space among actual or potential uses and activities.
Id. This rule works as a self-imposed limit on the Forest Service’s previously unbridled discretion in attaching terms and conditions to permits.
*543
Whether or not this interpretative rule preserves the constitutionality of the Forest Service’s noncommercial-group-use regulatory scheme, however, depends on whether the scheme, as limited by the narrowing construction, satisfies the traditional three-part test used to analyze the constitutionality of regulations governing the use of public forums.
5
Under this test, the government may regulate the time, place, and manner of expressive activity that occurs in a public forum so long as the regulatory scheme is (1) content-neutral, (2) narrowly tailored to serve a significant government interest, and (3) leaves open “ample alternatives for communication.”
Forsyth County v. Nationalist Movement,
The Forest System’s interpretative rule preserves the constitutionality of the regulatory scheme because the scheme now satisfies the three-part test for time-place-manner regulation. First, the rule limits the permissible range of terms and conditions to only those that pertain to health, safety, the environment, land-use management, and the minimization of damage to National Forest System resources.
See
64 Fed.Reg. 48,959 (1999). These concerns are content-neutral,
6
and therefore the scheme satisfies the first prong of the test.
See, e.g., United States v. Kistner,
*544 IV.
Relying on a recently promulgated interpretive rule to construe 36 C.F.R. § 251.56(a)(2)(vii) as constitutionally valid, however, raises a due process problem for Defendants. Although the Forest Service filed the information against Defendants in July 1998, the Forest Service did not promulgate the interpretative rule until September 1999.
See
64 Fed.Reg. 48,959 (1999). The regulation thus gave Defendants inadequate notice about the danger of being successfully prosecuted under this newly and narrowly construed regulatory scheme.
See Osborne v. Ohio,
AFFIRMED in part and REVERSED in part.
Notes
. 36 C.F.R. § 261.10(k) prohibits the use or occupation of “National Forest System land or facilities without special use authorization when such authorization is required.” 16 U.S.C. § 551 imposes a fine and/or imprisonment upon parties who violate Forest Service rules and regulations.
. 36 C.F.R. § 251.56(a)(2)(vii) is part of the Forest Service's regulatory scheme governing the "special use” of National Forest System land. Subject to certain exceptions not relevant here, any person wishing to engage in a special use of National Forest System land *541 must first obtain a permit. See 36 C.F.R. §§ 251.50(a) & 261.10(k).
36 C.F.R. § 251.56(a)(2) states that each "special use authorization” may contain such "terms and conditions as the authorized officer deems necessary to ... (vii) otherwise protect the public interest.”
. One type of special use is "noncommercial group use,” which 36 C.F.R. § 251.51 defines as "any activity conducted on National Forest System, lands involving a group of 75 or more people (a) for which no fee is charged or (b) where the primary purpose is not the sale of a good or service.”
. For the purposes of this appeal, the government has expressly assumed that the National Forest System is a public forum. Defendants do not dispute this characterization. We do not decide this issue here, but we note that at least one other circuit has suggested that National Forest System land is a public forum susceptible to time-place-and-manner restrictions. See
United States v. Johnson,
. A speech restriction is content-neutral if it is "justified without reference to the content of the regulated speech.”
Clark v. Community for Creative Non-Violence,
