Opinion by
JUDGE FOX,T1 Sara L. Burnett appeals the trial court's judgment dismissing her negligence claim against the Colorado Department of Natural Resources (CDNR). She contends that the trial court erred in determining that the CDNR did not waive immunity for her injuries under the Colorado Governmental Immunity Act (CGIA), section 24-10-106(1)(e), C.R.S8.2012. Because we conclude that there is no waiver of immunity under the CGIA for dangerous conditions in an unimproved area within a state park, we affirm the trial court's dismissal.
I. Background
T2 The facts recited here are not in dispute. Burnett was injured while camping in a designated campground in Cherry Creek State Park, which is operated by the CDNR. Burnett was sleeping in her tent in Campsite No. 14 when she was struck by a falling tree. branch. The branch likely came from a stand of trees adjacent to and overhanging Campsite No. 14. These mature cottonwood trees likely existed before the park was established in 1959.1 Some other campsites had no adjacent trees.
T3 Burnett brought a negligence claim against the CDNR for her injuries. The trial court dismissed her claim for lack of subject matter jurisdiction because the state is immune from all tort claims under the CGIA, except where immunity is expressly waived, and no waiver applied. § 24-10-106(1), C.R.S.2012. This appeal followed.
*855II. Standard of Review
T4 Because the parties stipulated to the relevant facts, the trial court did not conduct an evidentiary hearing. The trial court held, as a matter of law, that there was no waiver of immunity under the CGIA here. We review a trial court decision based on statutory interpretation de novo. Medina v. State, 35 P.3d 443, 452 (Colo.2001).
III. Analysis
15 The trial court held that while the campsite and campground were public facilities under the CGIA, the tree itself was not a public facility and the state retained immunity for injuries resulting from falling branches. See § 24-10-106(1)(e). Burnett contends that the trial court erred in dismissing her claim because the trees adjacent to Campsite No. 14 were part of a public facility, and the tree branches hanging over the campsite constituted a "dangerous condition of a public facility." See id.
16 Under the CGIA, the state waives immunity for injuries caused by a "dangerous condition of any ... public facility located in any park or recreation area maintained by a public entity." § 24-10-106(1)(e). The act further states, "[Injothing in this paragraph . shall be construed to prevent a public entity from asserting sovereign immunity for an injury caused by the natural condition of any unimproved property, whether or not such property is located in a park or reere-ation area." Id.
T7 The CGIA weakened the- common law of negligence by immunizing the government from tort liability, exeept where immunity is expressly waived. See § 24-10-106; Medina, 35 P.3d at 453; Herrera v. City & County of Denver, 221 P.3d 423, 425 (Colo.App.2009). We thus strictly construe its grant of immunity and interpret its waiver provisions broadly. Medina, 35 P.3d at 453; Herrera, 221 P.3d at 425. Nonetheless, we interpret a statute to give words and phrases their plain meaning in order to give effect to
the intent of the legislature. Medina, 35 P.3d at 453; Herrera, 221 P.3d at 425.
A. The Pre-Existing Tree Is Not a Public Facility
18 In determining that the tree from which the branch fell was not a public facility under the CGIA, the trial court followed Rosales v. City & County of Denver, 89 P.3d 507 (Colo.App.2004). In Rosales, a division of this court held that under the CGIA, a tree in a park or recreation area is not a public facility because a tree is not manmade or constructed. Id. at 510. The Rosales division concluded that the General Assembly intended the phrase "public facility" to mean something built or constructed by a public entity for a specific purpose.2 Id. at 509; see also Loveland v. St. Vrain Valley Sch. Dist. RE-1J, 2012 WL 2581034, 2012 COA 112, T 26, 328 P.3d 228 (cert. granted Feb. 25, 2018) (holding that under the CGIA, artificial playground equipment at a public school was a public facility because it was physically constructed). The Rosales division further concluded that a tree would be part of a public facility-and the state liable for injuries from it-only if it were "an integral part of the facility" and "essential for the intended use of the facility." 89 P.3d at 510.
«[ 9 We agree with the trial court's application of the Rosales test, and its determination that the tree adjacent to Campsite No. 14 is not a public facility. Trees are not integral to the use and enjoyment of a campsite merely because they provide shade, protection, and aesthetic values, and trees are not essential to the use of a campsite because campers do not need to use trees for camping. Indeed, the record reflects that some campsites in Cherry Creek State Park do not have adjacent trees.
B. No Waiver for Conditions in Unimproved Areas
110 According to Burnett, the campsite and surrounding trees are a "functional *856system" and collectively constitute a public facility for purposes of a CGIA waiver. We disagree.
T11 By its plain language, the CGIA expressly retains immunity for "an injury caused by the natural condition of any unimproved property, whether or not such property is located in a park or recreation area." § 24-10-106(1)(e). While the campground and Campsite No. 14 were in improved areas of Cherry Creek State Park, the trees adjacent to Campsite No. 14 were in an unimproved part of the park. If the General Assembly intended to waive immunity for all dangerous conditions in public parks, it would not have limited that waiver to public facilities in parks or expressly retained immunity for natural conditions in unimproved areas. See§ 24-10-106(l)(e); Rosales, 89 P.3d at 509.
{12 This interpretation is fully consistent with Colorado cases holding that a condition is "dangerous"3 for purposes of the CGIA's waiver of immunity only if it relates to the structural or physical condition of a facility or building. Padilla v. School Dist. No. 1, 25 P.3d 1176, 1183 (Colo.2001); Walton v. State, 968 P.2d 636, 645 (Colo.1998); Jenks v. Sulltvan, 826 P.2d 825, 827 (Colo.1992), overruled in part on other grounds by Bertrand v. Board of County Comm'rs, 872 P.2d 223 (Colo.1994); Douglas v. City & County of Denver, 203 P.3d 615, 618-19 (Colo.App.2008) ("The supreme court has indicated that, in order for a public entity's immunity to be waived under section 24-10-106(1)(c), the dangerous condition must be associated with the construction or maintenance of the building and stem from the use of a dangerous or defective physical condition of the building itself.").
13 In Jenks, the supreme court explained that in the CGIA's definition of "dangerous condition," the term "or the use thereof," means the use of a physical condition of a facility. 826 P.2d at 827. The Jenks court held that waiver only exists when injury is caused by a dangerous condition stemming from a physical or structural defect in a public building, not when it is caused merely by activities in a public building. Id. at 880 (holding that no waiver exists when plaintiff's injury was caused by a shooter on the steps of a courthouse because there was no physical or structural defect in the building).
1 14 In Walton, the supreme court stated, "Liability attaches for injury stemming from the public's use of a dangerous or defective physical condition of the building." 968 P.2d at 645 (holding that the state waived immunity for a student's injury when she fell off a ladder as a result of the university's negligent maintenance of a classroom).
15 In Padilla, the supreme court further clarified that waiver only exists when there is a defect in the physical structure itself, not when an injury is a result of the negligent use of a public facility. 25 P.3d at 1183 (holding that a plaintiff must "demonstrate a sufficient connection between use of the [building] and a construction or maintenance activity or omission for which the School District is responsible").
16 Two federal cases interpreting section 24-10-106(1)(e) hold that immunity is waived only when the alleged dangerous condition of , a public facility is of a physical improvement to the park or recreation area. DeAnzona v. City & County of Denver, 222 F.3d 1229, 1237 (10th Cir.2000) (holding that the natural condition of land, even within a park, cannot lead to waiver of immunity); King v. United States, 53 F.Supp.2d 1056, 1070-71 (D.Colo.1999) (holding that a fire pit built by students was not a dangerous condition of a physical improvement of government property), rev'd in part on other grounds, 301 F.3d 1270 (10th Cir.2002).
*857T17 We are not persuaded by Burnett's argument that the trees adjacent to Campsite No. 14 together with the campsite and campground form a "functional system," and thus constitute a public facility for purposes of waiving immunity under CGIA.
{18 In support of her argument, Burnett cites several cases holding that the state waived immunity for dangerous conditions of objects on a highway. See Medina, 35 P.3d at 458; State v. Moldovan, 842 P.2d 220, 225 (Colo.1992); Belfiore v. Colorado State Dep't of Highways, 847 P.2d 244, 246 (Colo.App.1998); Schlitters v. State, 787 P.2d 656, 658 (Colo.App.1989). These cases are distinguishable from the present case because the injuries in the highway cases arose from negligent maintenance of a highway, whereas here, Burnett's injuries were from natural conditions of an unimproved part of a state park.
{19 In Moldovan, $42 P.2d at 225, the Colorado Supreme Court held that a state-maintained fence adjacent to a highway was an integral part of the highway system, and the state was responsible, pursuant to CGIA section 24-10-106(1)(d) and not under section 24-10-106(1)(e),4 for keeping the fence in good repair to prevent it becoming a dangerous condition. The duty to maintain the highway and thus the fence, in turn, derived from another statute. See § 85-46-111(1)(a), C.R.S.2012. Here, Burnett fails to identify a corresponding duty to trim trees located in a natural area of a state park.
1120 Likewise, in Medina, 35 P.3d at 458, the Colorado Supreme Court held that the state is required to ensure a highway remains in the same general state of repair as when it was originally constructed. The court measured the seope of the state's duty-and the scope of the CGIA waiver-in relation to the original condition of the road. Id. at 448-49. Because the record did not disclose the state of the road as originally constructed, the supreme court could not determine if the alleged dangerous condition resulted from the lack of maintenance after initial design and construction of the road, or whether it came from the design itself. Id. at 449. Accordingly, it remanded the case for an evidentiary hearing. Id. In contrast, here Burnett and the state stipulated that the trees adjacent to Campsite No. 14 likely existed before Cherry Creek State Park was established. Unlike a constructed highway, the state did not create the stand of trees adjacent to Campsite No. 14, and thus it has no duty to maintain the trees relative to other pre-existing trees in other natural areas.
121 According to the Colorado Supreme Court, Belfiore and Schlitters-two cases Burnett relies upon-are "only marginally instructive" because they were decided pursuant to C.R.C.P. 12(b)(5), as opposed to C.R.C.P. 12(b)(1), and before Trinity Broadcasting, Inc. v. City of Westminster, 848 P.2d 916 (Colo.1998). Medina, 35 P.3d at 456. Both cases involved injuries to motorists when a boulder fell onto the highway. Belf-iore, 847 P.2d at 246 (holding that boulder fell as a result of blasting activities on adjacent property, about which the Department of Highways had advance notice); Schlitters, 787 P.2d at 658 (holding that Department of Highways negligently failed to install devices that would have prevented boulders from falling onto a highway). In both cases, the state had constructed the road and had an independent duty to maintain the road. No such independent duty to trim trees in natural areas exists here.
*8581 22 According to Medina, "Belfiore stands for no more than the legal proposition that if the plaintiffs injuries are the result of the state's negligent failure to maintain the right-of-way, then the CGIA waives the state's immunity in an action to recover therefor." 35 P.8d at 456. Similarly, Schiit-ters merely held that allegations that the state knew of numerous previous injuries involving falling rocks on the same segment of the road and negligently failed to install a device that would prevent rocks from falling were sufficient to state a claim for relief. 787 P.2d at 658. Here, however, Burnett did not allege that others were injured from tree branches falling from trees adjacent to Campsite No. 14 or that CDNR had notice that branches were falling from the tree or dangerously likely to fall.5
$23 To the extent that Burnett argues that the CDNR had a duty to maintain the trees around Campsite No. 14, she fails to cite any authority, and we have found none, creating an affirmative duty on the part of state park personnel to prune or otherwise maintain trees in a natural area of a state park. Colorado courts have held that the state is Hable for injuries caused only by its failure to maintain public buildings or highways in good repair. See Springer v. City & County of Denver, 18 P.3d 794, 804 (Colo.2000) (construing section 24-10-106(1)(c) waiver of immunity for dangerous conditions of public buildings); Swieckowski v. City of Fort Collins, 984 P.2d 1380, 1385 (Colo.1997) (construing section 24-10-106(1)(d) waiver of immunity for dangerous condition of a public highway). Colorado appellate courts have not, however, found that the state has a duty to maintain unimproved areas in parks or recreation areas. Burnett's proposed interpretation would unnecessarily expand the CGIA.
( 24 We decline to consider any arguments Burnett now makes that the trial court did not address. See, eg., Akin v. Four Corners Emecampment, 179 P.8d 189, 147 (Colo.App. 2007) (declining to consider whether petitioners had a statutory right to amend their petition because the argument was not presented to the district court).
IV. Conclusion
125 By the plain meaning of the CGIA, the CDNR retains immunity for injuries from branches falling from trees in unimproved parts of a state park. § 24-10-106(1)(e). We thus conclude that the trial court did not err in dismissing Burnett's negligence claim because the CDNR did not waive immunity for her injuries.
126 Judgment affirmed.
JUDGE MILLER concurs. JUDGE CARPARELLI dissents.. The parties stipulated to the park manager's affidavit, which stated that none of the trees were on improved portions of Campsite No. 14, none of the trees were planted by state or park personnel, and the trees were mature cottonwoods that likely existed before the park was created in 1959.
. This conclusion was based on Webster's Third New International Dictionary 812-13 (1986) definition of "facility" as something that is built or constructed for a particular purpose and the placement of the phrase "public facility" in section 24-10-106(1)(e) with other constructed facilities, ie., public hospital, jail, water facility, gas facility, sanitation facility, and electrical facility. Rosales, 89 P.3d at 509.
. The CGIA's definition of "dangerous condition" is: >
either a physical condition of a facility or the use thereof that constitutes an unreasonable risk to the health or safety of the public, which is known to exist or which in the exercise of reasonable care should have been known to exist and which condition is proximately caused by the negligent act or omission of the public entity or public employee in constructing or maintaining such facility.
§ 24-10-103(1.3), C.R.S.2012. Having concluded that there was no waiver of immunity, the trial court here did not need to decide whether a dangerous condition existed.
. CGIA section 24-10-106(1)(d), as it existed at the time of Moldovan's injuries, waived immunity for dangerous conditions of a public highway as follows:
Sovereign immunity is waived by a public entity in an action for injuries resulting from:
A dangerous condition of a public highway, road, or street which physically interferes with the movement of traffic on the paved portion .. of any public highway, road, [or] street.... As used in this section, the phrase "physically interferes with the movement of traffic' shall not include traffic signs, signals, or markings, or the lack thereof, but shall include the failure to repair a stop sign or a yield sign which reassigned the right-of-way or the failure to repair a traffic control signal on which conflicting directions are displayed, if such failure constituted a dangerous condition
Ch. 166, sec. 5, § 24-10-106(1)(d), 1986 Colo. Sess. Laws 876.
. Burnett waived her right to an evidentiary hearing, pursuant to Trinity, by stipulating to the facts, and thus failed to develop a further record.