County of San Mateo v. Superior Court

Filed 7/25/17
CERTIFIED FOR PUBLICATION

IN THE COURT OF APPEAL OF THE STATE OF CALIFORNIA

FIRST APPELLATE DISTRICT

DIVISION TWO

COUNTY OF SAN MATEO,
Petitioner,
v.
THE SUPERIOR COURT OF SAN A146077
MATEO COUNTY,
(San Mateo County
Respondent; Super. Ct. No. CIV 515962)
ZACHARY ROWE et al.,
Real Parties in Interest.

A 72-foot diseased tree fell on a sleeping child’s tent pitched in a campground that
is located within a vast public wilderness park. The park’s owner, the County of San
Mateo, contends it is immune as a matter of law for this allegedly dangerous condition of
its property under Government Code section 831.2, commonly referred to as the “natural
condition immunity.” It states: “Neither a public entity nor a public employee is liable
for an injury caused by a natural condition of any unimproved public property, including
but not limited to any natural condition of any lake, stream, bay, river or beach.”1 (See
§ 831.2.)
The trial court denied the County’s motion for summary judgment under section
831.2, and we now deny the County’s petition for a writ of mandate seeking to overturn

1
All further statutory references are to the Government Code unless otherwise
indicated.

1
the summary judgment ruling. We conclude there are triable issues of fact as to whether
the property here was “unimproved.”2
BACKGROUND
On July 25, 2012, Zachary Rowe and his family were camping in San Mateo
County Memorial Park, where they occupied campsite D-1 of Sequoia Flat Campground.
Twenty feet from Zachary’s tent stood a 72-foot, diseased tanoak tree suffering from a
species of fungus called Armillaria that caused it to fail. In the early morning hours,
while Zachary was sleeping, the massive tree fell on Zachary’s tent, crushing him and
inflicting catastrophic injuries. The tree also crushed a nearby picnic table. It came to
rest on a bumper log located within campsite D-1, 42 feet from the tree’s broken end.
San Mateo County Memorial Park is property owned by San Mateo County,
consisting of approximately 499 wooded acres, with trails. Its campsites are located in a
heavily wooded campground area, portions of which were cleared of trees. The
campground area contains dozens of campsites as well as amenities such as paved roads,
telephones, restrooms (with electricity, sinks and flush toilets), showers, dedicated
parking areas, a dumping station and a store. An official campground map depicting the
campground’s layout and some of its amenities is reproduced in the appendix to this
opinion as Figure 1.
Zachary’s campsite consisted of a clearing with two picnic tables, a fire pit and a
metal food locker. His tent was approximately 20 feet from the broken edge of the tree.
A power line runs along an adjacent road and is visible from where the tree stood.
The tree was 20 feet away from a paved access road and surrounded by a cluster of
five campsites, including Zachary’s. A professional land surveyor determined there were
34 man-made improvements within 126 feet of where the tree stood, including roadways,
bumper logs (which are large trees laid on the ground to keep cars out of camping areas),

2
This case arises from the same incident as Pacific Gas & Electric Co. v.
Superior Court (2017) 10 Cal.App.5th 563, in which we addressed a co-defendant’s
claim of recreational use immunity under Civil Code section 846. That statute is not at
issue here.

2
restrooms, picnic tables, bear boxes, fire pits/barbeque pits, road signs, conductor poles
with transformers and a parking bollard. According to the survey map he prepared,
which is reproduced as Figure 2 in the appendix to this opinion, the man-made objects
closest to the tree were a picnic table and a fire pit in a neighboring campsite, both some
13 feet away from the tree. The map depicts many man-made objects within the tree’s
72-foot striking distance, including a power line within 37 feet at its closest point; two
access roads, one of which was 22 feet away at its closest point and the other 61 feet
away; and various amenities located in Zachary’s campsite and several neighboring
ones.3 Also close by, but not within the tree’s 72-foot striking distance, were two
restrooms, one 113 feet away from the tree, and the other 126 feet away.
Since at least 1993, the County has inspected what it considers to be “developed
areas” of the park for hazardous trees and removed them. It considered Sequoia Flat
Campground to be a developed area.
The Pleadings
Zachary, by and through his guardian ad litem, sued the County for premises
liability (§ 815.2) and dangerous condition of public property (§ 835). He alleged the
tree had identifiable structural defects, including rot, a cavity and a denuded trunk and
“was overextended, tilted and had poor taper.” He alleged the County negligently failed
to maintain campsite D-1 and its environs, failed to warn of or protect against the danger
of falling trees, failed to inspect, care for, treat or trim the trees, and knew or should have
known that the tree that fell was infected and posed a severe risk of injury yet failed to
remove it.
Zachary also alleged, “[c]ampsite D-1 is one of many campsites located in a
designated campground area of San Mateo Memorial State Park. These campsites were

3
Aside from Zachary’s tent itself, those objects were the amenities in neighboring
campsite C-33 (bumper logs, two picnic tables, and a fire pit); the fire pit, bear box, and
picnic table in Zachary’s campsite (all within 61 feet to 70 feet of the tree); two bumper
logs and a bear box in neighboring campsite D-10; and two picnic tables and a fire pit in
another neighboring campsite (within 50 and 67 feet away, in campsite C-31).

3
created by the defendants who selected the location, created the design, cleared the
vegetation in designated areas of the park, and improved the areas with picnic tables,
barbeque grills, bathrooms and showers and otherwise improved these sites to
accommodate high use, multi-day tent camping by the public.”
The Summary Judgment Motion
The County moved for summary judgment on the ground that it was immune as a
matter of law under section 831.2. It argued, first, that the tree that injured Zachary was a
natural condition. It then rebutted several arguments it anticipated from Zachary as to
whether the property was unimproved. The County contended, first, that the presence of
bathrooms, showers and other amenities located elsewhere in the park other than at
campsite D-1, as alleged in the complaint, did not vitiate its immunity. It also contended
that Zachary “cannot argue that Section 831.2 immunity does not apply . . . by arguing
that he was injured in a campsite ‘improved’ for campers . . . because the cause of his
injury was the tree, a natural condition of the land.” Finally, the County argued there was
no evidence that its creation of campsite D-1 contributed to the accident. In support, it
relied on the declaration of a certified arborist, Barnard Noonan, who had inspected the
tree, the campsite and the surrounding area and opined that, “[t]he base of the tree was
adjacent to the campsite. I saw nothing at the campsite to suggest that any human
activity had caused or contributed to the tree having fallen across the campsite.”
According to Noonan, “the tree was in a natural condition when it failed, and it failed as
the result of a progression of infection by a naturally-occurring fungus.”
In opposition, Zachary introduced evidence that, among other things, man-made
changes during construction of the campgrounds made the tree more susceptible to
developing Armillaria. Specifically, in the opinion of arborist Roy Leggitt, “the
manmade developments in Memorial Park, and the Sequoia Flat Campgrounds created by
development, urbanization, construction and intense camping uses more likely than not
created conditions that directly led” to the tree’s infection by Armillaria and ultimately to
its failure. He averred that, “Site conditions favorable to the development of Armillaria
were created at the time of construction of this campsite and nearby improvements over

4
the years.” Among other things, “[c]onstruction activity changed the nature of the soil
and the root environment” in the tree’s vicinity, which included “removal of adjacent
trees, removal of mulch to bare dirt, grading of the soil for the road, soil compaction
beneath the road, parking areas nearby and within the campsite, and changes in
drainage,” as well as clearing soil of all organic material and compacting it in order to
construct roadways, parking areas and campsites, and in his opinion “[t]hese construction
activities have negatively impacted tree health through soil and root damage.” And,
according to Leggitt, “construction activities and ongoing uses” caused the roots to
gradually die from oxygen starvation. In addition, he stated the extensive removal of
trees created favorable conditions for Armillaria because it left behind dead stumps and
roots that are hosts for the fungus.
Zachary also submitted the declaration of horticultural pathologist James Downer
opining that, “the man-made changes to the area around Campsite D-1, including the
cutting and paving of nearby roads; creation of campsites and vehicle parking areas, and
visitor traffic around the campsite predisposed the failed tree to becoming infected with
Armillaria,” and “the physical changes made to the area substantially increased the
likelihood that the subject tree would become infected and ultimately contributed to its
failure.” His opinion was based upon the fact that trees are more susceptible to the
disease when, among other things, soils “have been compacted by the construction of
nearby roads, foot traffic, vehicle parking or other means.”
The trial court concluded there was a triable issue of fact as to whether the
property is unimproved, and denied the County’s motion. It ruled principally on the basis
of evidence that, at the time of the accident, both Zachary and the tree that fell on him
were located within campsite D-1, that campsite D- 1 had been “improved” by a clearing,
picnic tables, a fire pit, and bumper logs to indicate areas for parking cars, and that in the
tree’s immediate vicinity were two other, developed campsites and a paved roadway.
The court also relied upon the experts’ opinions that those “man-made changes altered
the characteristics of property surrounding the tree and contributed to the tree’s failure by
making the tree more susceptible to Armillaria.”

5
 The County’s petition for writ of mandate followed.
DISCUSSION
Summary judgment must be granted if all the papers submitted below show there
is no triable issue of any material fact, “that is, there is no issue requiring a trial as to any
fact that is necessary under the pleadings, and ultimately, the law.” (Aguilar v. Atlantic
Richfield Co. (2001) 25 Cal.4th 826, 843; Code Civ. Proc., § 437c, subd. (c).) In
evaluating that question, we do not review the trial court’s reasons for its summary
judgment ruling but only its ruling—that is, “whether the judge reached the right
result . . . whatever path he might have taken to get there, and we decide that question
independently of the trial court.” (Carnes v. Superior Court (2005) 126 Cal.App.4th
688, 694, fn. omitted; accord, Ram’s Gate Winery, LLC v. Roche (2015) 235 Cal.App.4th
1071, 1079 [trial court’s stated reasons for summary judgment ruling “are not binding on
us because we review its ruling, not its rationale”].)
I.
The Natural Condition Immunity: An Overview
Section 831.2 is part of the Government Claims Act of 1963 (§ 810 et seq.), a
comprehensive statutory scheme governing the liabilities and immunities of public
entities and their employees. (Alana M. v. State of California (2016) 245 Cal.App.4th
1482, 1487 (Alana M.); Milligan v. City of Laguna Beach (1983) 34 Cal.3d 829, 831
(Milligan).) Its purpose is to encourage public use of unimproved government property
by relieving government agencies from being “put to the expense of making the property
safe, responding to tort actions, and paying damages.” (Milligan, at p. 833; accord, Delta
Farms Reclamation District v. Superior Court (1983) 33 Cal.3d 699, 1174 [purpose is to
“open[] up public property for recreational use by making it financially safe to do so”];
see also Alana M., at p. 1487.)
A legislative comment formally adopted by committees of the Senate and
Assembly sheds light on the Legislature’s goal. (Milligan, supra, 34 Cal.3d at pp. 831–
832.) It states: “ ‘This section [831.2] provides an absolute immunity from liability for
injuries resulting from a natural condition of any unimproved public property. Thus, for

6
example, under this section and Section 831.4,[4] the State has an absolute immunity from
liability for injuries resulting from natural conditions of a state park area where the only
improvements are recreational access roads (as defined in Section 831.4) and hiking,
riding, fishing and hunting trails. [¶] This section and Section 831.4 continue and extend
an existing policy adopted by the Legislature in former Government Code Section 54002.
It is desirable to permit the members of the public to use public property in its natural
condition and to provide trails for hikers and riders and roads for campers into the
primitive regions of the State. But the burden and expense of putting such property in
safe condition and the expense of defending claims for injuries would probably cause
many public entities to close such areas to public use. In view of the limited funds
available for the acquisition and improvement of property for recreational purposes, it is
not unreasonable to expect persons who voluntarily use unimproved public property in its
natural condition to assume the risk of injuries arising therefrom as a part of the price to
be paid for benefits received.” (Milligan, supra, 34 Cal.3d at pp. 832–833, italics added.)
The Supreme Court has directed courts to apply the natural condition immunity “in
accordance with [this] expressed purpose and refuse to apply it when application would
not further the expressed purpose.’ ” (Id. at p. 832.)
As this court has explained, the statute presents two fact questions: whether a
condition is “natural” and whether the property is “unimproved” public property. (Fuller
v. State of California (1975) 51 Cal.App.3d 926, 937 (Fuller).) Here, Zachary does not
contend the accident was caused by a non-natural condition. Therefore, the only issue we
address is whether the County demonstrated as a matter of law the accident was caused
by a condition of “unimproved” public property. (§ 831.2.)

4
Section 831.4 grants public entities a separate immunity for injuries caused by a
condition of unpaved roads providing access to recreational areas such as fishing,
hunting, camping, and hiking grounds, and for paved trails providing access to any
unimproved property.

7
 The statute does not define the phrase “unimproved public property,” nor does it
establish any standard for determining when public property ceases to be ‘unimproved’ as
the result of development activity. (Keyes v. Santa Clara Valley Water District (1982)
128 Cal.App.3d 882, 887–888 (Keyes).) It is well-settled, however, that improvements in
one portion of public property do not destroy governmental immunity for unimproved
areas. (Rendak v. State of California (1971) 18 Cal.App.3d 286, 288 (Rendak).) This
court and others have applied Rendak, and upheld immunity, in a variety of
circumstances where the only amenities argued to constitute improvements have been
located some distance from the accident scene. (See, e.g., Fuller, supra, 51 Cal.App.3d
at pp. 934–935, 936–937 [narrow, rocky, point of land from which plaintiff dove into
ocean held not improved as a matter of law despite lifeguard towers, restrooms and fire
rings located on nearby beach; under Rendak, “the immunity granted by [section 831.2] is
to be given a broad application”]; Eben v. State of California (1982) 130 Cal.App.3d 416,
423 (Eben) [area of lake where waterskiing accident occurred held not “improved” by
placement of warning buoys “located in an area some distance from the accident scene”];
Geffen v. County of Los Angeles (1987) 197 Cal.App.3d 188, 194–195 [area of beach
where diving accident occurred held unimproved, despite lifeguard building, lifeguard
towers, parking lots, food concessions, a promenade, breakwater, pier, and signage
located elsewhere on beach at unspecified location(s)].)
Beyond Rendak’s holding that section 831.2 applies to unimproved areas that are
“separate, distinct and remote” from improved portions of public property (see Rendak,
16 Cal.App.3d at p. 289), however, there is tension in the case law concerning various
issues bearing on whether property is “unimproved.” Given the manner in which the
parties have framed the legal question before us, we address and resolve only those issues
that are necessary to our decision.

8
 II.
Location of Injury Versus Location of the Natural Condition
One area where the cases have diverged is how courts are to specify the relevant
area of property for purposes of assessing whether it is improved or unimproved.
Rendak’s early progeny developed the rule that “some form of physical change in the
condition of the property at the location of the injury is required.” (Eben, supra,
130 Cal.App.3d at p. 421; see also, e.g., Keyes, supra, 128 Cal.App.3d at pp. 887–888;
Tessier v. City of Newport Beach (1990) 219 Cal.App.3d 310, 315 (Tessier).)
The first case to part ways with that rule was Meddock v. County of Yolo (2013)
220 Cal.App.4th 170 (Meddock), which held a public entity immune from suit by a
plaintiff who was injured when standing in an improved area of public property (the
paved parking lot of a boat ramp) when a tree growing in a nearby area fell on him. The
court in Meddock assumed, but did not decide, that the tree itself was located on
unimproved property. (See id. at p. 177.) In that context, Meddock held it was irrelevant
that the tree fell, and caused injury to the plaintiff, on the improved portion of the public
property, principally because of the statute’s causation requirement. It reasoned, “[t]he
statutory immunity extends to ‘an injury caused by a natural condition of any
unimproved public property.’ (§ 831.2, italics added.) The use of the term ‘caused’ is
significant. [Citation.] Here, although the injury occurred on improved property, that is,
the paved parking lot, it was caused by the trees, native flora located near—and perhaps
superjacent to—the improved parking lot, but themselves on unimproved property.”
(Ibid., fn. omitted.) Meddock held that “the location of the occurrence is not material to
the statute.” (Id. at p. 179, italic omitted.) It concluded that because the plaintiff’s
injuries “were caused by decaying natural trees located on unimproved property,” the
county was immune. (Id. at p. 182.)
Relying in part on Meddock and distinguishing prior authorities, our colleagues in
Division Three recently announced the rule that “[w]hen the location of the injury is
different from the location of the natural condition, the character of the location of the
injury is not relevant.” (Alana M., supra, 245 Cal.App.4th at p. 1489.) Alana M. found

9
textual support in the statute; it reasoned that “because the phrase ‘of any unimproved
public property’ in section 831.2 modifies the ‘natural condition’ that caused the injury,
the relevant issue for determining whether the immunity applies is the character
(improved or unimproved) of the property at the location of the natural condition, not at
the location of the injury.” (Ibid.)
Applying these principles, Alana M. held a public entity immune from suit when a
tree fell and injured a child sleeping in a tent in a state-owned campground. It held the
tree was a natural condition of “unimproved” property as a matter of law, despite the fact
it “fell on an improved campsite.” (Alana M., supra, 245 Cal.App.4th at p. 1491.) In
part the court reasoned, “[t]here is no evidence of any artificial physical change in the
condition of the tree . . . or of the land within 24 feet of the tree.” (Ibid.) And the court
held the fact the tree was tall enough to fall within the plaintiff’s campsite “does not show
the tree that fell was on improved property.” (Id. at p. 1492.) Nor did evidence that the
tree was subject to the state’s tree hazard inspection program which, according to the
state’s operational manual, applied “ ‘solely within the developed areas’ ” of state parks;
Alana M. held the defendant’s “belief that the tree was on improved property is not
competent evidence” but merely a legal conclusion.5 (Id. at pp. 1486, 1493, italics
omitted.)
In evaluating whether Zachary’s injuries were caused by a “condition of
unimproved property,” our task in this case, as it was in Meddock and Alana M., is
somewhat complicated by the fact that the peril here—a falling tree—did not have a fixed
location. In effect, it was a migratory danger; it began in one location but ended up, and
caused injury, in another. The same was true in Rendak, the first reported opinion to
construe the statute, which involved a landslide from a cliff high above a strip of beach
that killed a visitor walking on the beach below. (See Rendak, supra, 18 Cal.App.3d at
pp. 287–288.) However, in holding the state was immune as a matter of law, Rendak,

5
This aspect of Alana M. forecloses Zachary’s argument that the County’s tree
inspection program has any bearing on whether the property here is improved.

10
unlike Meddock and Alana M., did not consider the characteristics of the condition’s
location (i.e., the (obviously) unimproved cliff) but, rather, the characteristics of the
beach some 72 feet below where the hazard struck.6
Nevertheless, we do not need to decide whether and to what extent the location of
the condition, or the location of injury, controls when dealing with a transitory hazard
because in this case, unlike in either Meddock or Alana M., there is evidence from which
a trier of fact could conclude the diseased tanoak tree was not in a different location than
the site of the accident, and was growing in an improved area.7
First, unlike in Alana M., there is evidence the trunk of the tree was growing
within the boundary of Zachary’s own campsite which, for the reasons discussed post, we
conclude raises a triable issue of fact as to whether the campsite is unimproved.

6
In its discussion of the relevant facts, for example, Rendak noted that “[a] rest
room appears to be the nearest improvement to the site of the fatal accident here
involved, and it is some 650—900 feet from the accident site.” (Rendak, supra,
18 Cal.App.3d at p. 287, italics added.) The court also reasoned, among other things, that
section 831.2 “specifically extends the immunity to ‘any natural condition of any . . .
beach’ ”—an obvious reference to the accident site, not the cliff above where the danger
originated. (Rendak, at p. 288, italics omitted.)
Alana M. said that “[i]n Rendak, the dangerous condition and the area where the
decedent died were generally the same location.” (Alana M., supra, 245 Cal.App.4th at
p. 1490, citing Rendak, supra, 18 Cal.App.3d at pp. 287–289.) But the dangerous
condition in Rendak, initially before it struck, was farther away from the accident victim
than in Alana M. It was a 72-foot high cliff that collapsed into the sea on top of the
victim. (See Rendak, supra, at pp. 287–288.) In Alana M., by contrast, the tree that
crashed onto the plaintiff’s tent had been growing just 60 feet away from the campsite
before it fell. (See Alana M., at p. 1485.) This was four feet closer to the victim before it
struck than the cliff that collapsed in Rendak.
7
Another decision dealing with a transitory hazard, to which the County at oral
argument likened this case, is Arroyo v. State of California (1995) 34 Cal.App.4th 755,
which held that section 831.2 applied as a matter of law to a personal injury suit brought
by a child who was mauled by a mountain lion while walking on a hiking trail in a state
park. Arroyo is irrelevant, though, because the question whether the property was
“unimproved” was not at issue. (See id. at pp. 760–761.) The court merely held the lion
was a natural condition, notwithstanding various arguments to the contrary. (See id. at
pp. 761–762, 764–765.)

11
Although the County disputed the tree’s location, the incident report described the tree as
“located in the north end of campsite D-1”, and one of Zachary’s experts, arborist Roy
Leggitt, stated in a declaration it was “located within” that campsite. Furthermore,
regardless of the trunk’s location, Zachary also introduced evidence that the tree’s roots
would have been growing underneath the campsites: according to his expert Leggitt,
“The root system for the 72-foot tall tanoak tree that failed, under normal conditions,
would extend at least 50–60 feet out from the trunk of the tree in all directions. Thus, the
root system under normal conditions would extend beneath Campsite D-1 and the
adjacent campsites, the parking areas for nearby vehicles, and beneath the paved road
adjacent to the tree.” Obviously, a tree’s roots are part of the tree; indeed, in this case the
weakening of the roots, according to Leggitt, contributed to the tree’s failure. According
to Leggitt, the tree’s roots deteriorated over time “as oxygen-starved roots have gradually
died from construction activities and ongoing uses.”
Second, the trunk of this tree was considerably closer to the improved accident site
and surrounding amenities than was true in Alana M. Whereas in Alana M. the tree was
growing 60 feet away from the injured victim’s campsite (see Alana M., supra,
245 Cal.App.4th at p. 1485), the tree that fell on Zachary was roughly 20 feet from where
his tent was pitched.8 It also was only 13 feet away from the nearest manmade objects
depicted in the surveyor’s map (a picnic table and a fire pit), compared with 30 feet in
Alana M. (a picnic table). (See ibid.)
And finally, unlike in Alana M., there also is evidence of physical alterations at the
site where the tree grew. Zachary’s expert James Downer opined that “[t]he soil around
the stump of the failed tree . . . was bare, compacted and lacking litter in 2014 and thus
likely low in recycled organic . . . nutrients.” And according to arborist Leggitt,
“[c]onstruction activity changed the nature of the soil and the root environment in the

8
The precise distance between the broken tree stump and Zachary’s tent does not
appear to be in the record. However, a map of measurements attached to the incident
report depicts the stump in extremely close proximity to the broken end of the tree, which
was itself 20 feet from the tent.

12
vicinity of the subject tree,” and he explained at some length how the removal of mulch
during campground construction, and the removal of trees “in the area immediately
surrounding the subject tree” damaged the tree’s health by impairing the level of nutrients
in the soil and, ultimately, damaging the tree’s roots. He also opined that the removal of
other trees in the vicinity during campground construction created a clearing around this
tree that caused it to grow asymmetrically toward sunlight, and made it susceptible to
torsional loads from high winds.
In sum, there are triable issues of fact as to whether the tree was growing in the
same general location as the accident site or, even if it was not, was itself growing in an
improved area by virtue of the artificial physical changes in its immediate vicinity.
III.
On This Record, There Are Triable Issues of Fact As to Whether the Campsite Area
Where Zachary Was Injured Is “Unimproved” Property.
This brings us, next, to whether the cluster of campsites where Zachary’s was
located is “unimproved” as a matter of law, as the County contends, or whether Zachary’s
evidence raises triable issues of fact concerning that issue. Given the above-discussed
evidence indicating the tree was within Zachary’s campsite, it is necessary for us to
address this issue.
The County argues that the “primitive amenities” within the campground or the
campsites themselves don’t render the area improved. Citing Mercer v. State of
California (1987) 197 Cal.App.3d 158, 165, it contends “[t]he Legislature could not
have intended the immunity to be avoided by the presence of simple accoutrements like
campsites with picnic tables, and access roads to get there,” because the statute “should
not be interpreted to ‘thwart accessibility and enjoyment of public lands by discouraging
the construction of such improvements as restrooms, fire rings, campsites . . . .’ ”
However, the County has quoted a portion of Mercer out of context; Mercer assumes
campsites are improvements. Addressing the Rendak principle that “improvements of a
portion of a public park do not remove the immunity from the unimproved areas,”
Mercer explained: “The reasonableness of this rule is apparent. Otherwise, the

13
immunity as to an entire park area improved in any way would be demolished.
[Citation.] This would, in turn, seriously thwart accessibility and enjoyment of public
lands by discouraging the construction of such improvements as restrooms, fire rings,
camp sites, entrance gates, parking areas and maintenance buildings.” (Mercer, at
p. 165.) In other words, Mercer was saying, if the construction of improvements such as
restrooms and camp sites destroyed immunity for an entire park, then a public entity
might be deterred from building those kinds of improvements in order to retain immunity
for unimproved areas. Mercer was not saying that immunity should apply to the areas
where such amenities were constructed, in order to encourage their construction.
In that respect, Mercer does not stand alone. The courts have generally
understood campsites with amenities to be improved, including the court in Alana M.
(See Alana M., supra, 245 Cal.App.4th at pp.1485, 1491 [noting that tree fell “on an
improved campsite” which consisted of a leveled area for tent, fire pit, picnic table with
benches and small wooden foot locker]; Meddock, supra, 220 Cal.App.4th at p. 180
[“ ‘camping sites with stoves, running water, sanitary facilities, garbage service and
organized recreational activities . . . would be excluded from the scope of this suggested
immunity’ ”], italics omitted, quoting Van Alstyne, A Study Relating to Sovereign
Immunity (Jan. 1963) 5 Cal. Law Revision Com. Rep. (1963) pp. 495–496).)
The County also argues the amenities here are “trivial,” but we disagree. Befitting
a campground, they are of course modest. But, based on this record, there can be no
question that the area where this cluster of campsites is located has undergone significant
artificial physical change, and is no longer in a natural state. (Cf. Buchanan v. City of
Newport Beach (1975) 50 Cal.App.3d 221, 227 (Buchanan ) [“an improvement … does
not necessarily mean the building of structures”].) The nearby paved road is an
improvement too, as reflected by the legislative committee comment we previously
quoted which characterizes “recreational access roads” as improvements, yet notes those
kinds of roads are protected by the separate immunity of section 831.4. (Milligan, supra,
24 Cal.3d at pp. 832–833.) None of the authorities cited by the County supports its
characterization of these changes as “trivial.” For example, the County cites our decision

14
in Fuller where amenities such as fire pits and restrooms on a beach did not render a
nearby rocky cliff “improved”; the reason, though, was not because of the nature of those
amenities but, rather, their distance from the accident site. (See Fuller, supra,
51 Cal.App.3d at pp. 936–937.) The County also cites Bartlett v. State of California
(1988) 199 Cal.App.3d 392, in which the court held that sand dunes on a portion of state
beach used as a recreational area for all-terrain vehicles were not improved even though
the state posted usage and speed limit signs nearby and provided some toilets at an
unspecified location. (See id. at pp. 396, 398.) But the evidence Zachary introduced
indicates that in Memorial Park the County did far more.
Zachary’s evidence showed the County: artificially altered the terrain by
removing nutrient-rich mulch down to bare dirt, and by installing a paved road, which
caused soil to become compacted and increased water run-off there which often causes
soil to become over-saturated; partially cleared the area of trees; and constructed
rudimentary amenities to facilitate cooking, eating and overnight sleeping in the area
where Zachary was injured and where the tree itself grew. This evidence raises triable
issues of fact as to whether the campsite was unimproved within the meaning of the
immunity statute.
Finally, the County argues that the policy implications of treating campsites as
improved are untenable. “[I]f a simple campsite in a forested mountainside is ‘improved’
for purposes of Section 831.2,” it contends, “then public owners of such property will be
faced with the ‘Hobson’s choice’ that the statute was enacted to avoid. To use Memorial
Park as an example, the County would be forced to eliminate campsites, remove roads to
access the interior of the park, and police hikers to assure they did not damage brush or
natural mulch. The alternatives would be to risk potentially ruinous liability or close the
parks altogether.”
We do not agree. A ruling that the County has improved one portion of its vast
public wilderness park by building improved campsites would not destroy immunity for
unimproved portions of the park. (Rendak, supra, 18 Cal.App.3d at pp. 288–289.) The
public would be free to use those areas, and would assume the risk of any dangers they

15
pose, exactly as the Legislature intended. (See Milligan, supra, 34 Cal.3d at p. 833.)
And although the County theoretically might consider eliminating improvements such as
campsites rather than shoulder responsibility for keeping those improved areas safe, such
a choice would not undermine the statute’s purpose. Section 831.2’s goal is to encourage
recreational use of unimproved public land (Milligan, at pp. 832–833), not to encourage
the construction of amenities and improvements on public property. Nor would interior
access roads be imperiled; they are protected by the separate statutory immunity of
section 831.4. In short, we do not think treating this cluster of campsites as “improved”
property for purposes of section 831.2 thwarts the Legislature’s goals.
In any event, we conclude that the evidence here raises triable issues of fact as to
whether the cluster of campsites where campsite D-1 is located is “unimproved”
property.
IV.
There Are Triable Issues of Fact As to Whether Artificial Changes Contributed to the
Tree’s Dangerousness.
The final issue the parties have raised, and another area in which the authorities
are somewhat in tension, is whether proof of a causal link between physical changes and
the accident is either necessary and/or sufficient for property to be considered
“improved.” Specifically, there is tension in the case law as to the legal significance of
evidence that artificial, physical changes to the environment have contributed to or
exacerbated a naturally occurring danger. Broadly speaking, some authorities have held
such changes to be legally insufficient to defeat immunity (principally addressing the
issue in the context of what constitutes a “natural” condition) (see, e.g., Goddard v.
Department of Fish and Wildlife (2015) 243 Cal.App.4th 350, 361 [“section 831.2 has
been broadly construed to provide immunity even where a natural condition has been
affected in some manner by human activity or nearby improvements”]; Knight v. City of
Capitola (1992) 4 Cal.App.4th 918, 927–929 (Knight); Tessier, supra, 219 Cal.App.3d at
pp. 313–315; Morin v. County of Los Angeles (1989) 215 Cal.App.3d 184, 189–190
(Morin); Fuller, supra, 1 Cal.App.3d at pp. 937–938; cf. Schooler v. State of California

16
(2000) 85 Cal.App.4th 1004, 1009–1010 [construing § 831.25]); one has held them
legally sufficient (see Buchanan, supra, 50 Cal.App.3d at pp. 225–2289); and most
recently, our colleagues in Division Three in Alana M. held such proof legally required,
as an additional element to be satisfied. According to Alana M., “immunity applies
unless an improvement or human conduct created, contributed to, or exacerbated the
degree of, the danger associated with a natural condition.” (Alana M., supra, 245
Cal.App.4th at p. 1489.) Stated otherwise, Alana M. required proof of “ ‘a causal nexus
between the dangerous condition and either human conduct or an artificial
improvement.’ ”10 (Ibid.)
It is unnecessary for us to examine these authorities at any length, or attempt to
reconcile them. Here, although the County argues that “a public property owner is
immune from liability for injury from natural conditions regardless of whether human
agency has contributed to risks attendant on those conditions,” and that the trial court
erred in denying summary judgment because evidence that human activity accelerated the

9
Later cases have limited Buchanan to its facts, but none have disagreed with it.
(See Knight, supra, 4 Cal.App.4th at p. 929 [“an extreme case” involving “unusual
facts”]; Morin, supra, 215 Cal.App.3d at pp. 189–190 [Buchanan involved improvements
that “physically alter[ed] the accident site”]; see also Tessier, supra, 219 Cal.App.3d at
pp. 314–315; Geffen v. County of Los Angeles, supra, 197 Cal.App.3d at p. 195, fn. 4;
Eben, supra, 130 Cal.App.3d at p. 425 [distinguishing Buchanan where improvements
“were few in number and remote from the accident site, which was unimproved” and
there was no evidence “link[ing] the improvements, casually or otherwise, with the
accident”]; see also Mercer, supra, 197 Cal.App.3d at p. 165 [Buchanan illustrates the
principle “that to qualify public property as improved . . . the improvements must change
the physical nature or characteristics of the property at the location of the injury to the
extent that it can no longer be considered in a natural condition”].)
10
Applying that principle, Alana M. concluded section 831.2 applied in that case,
in part because there was no evidence that artificial improvements or human conduct
contributed to the tree’s danger in that case, such as evidence “that leveling the area of
the campsites weakened the tree and made it more likely to fall.” (Alana M., supra, 245
Cal.App.4th at p. 1491.) Alana M. also held the required causal nexus could not be
established by the fact the improved campsites would attract people to the area, and thus
increase the likelihood someone would be injured by a falling tree. (See id. at pp. 1491–
1492.)

17
effect of Armillaria infection was legally irrelevant, elsewhere in its briefing the County
appears to concede that changes to the natural environment of public property that bear
some causal connection to a plaintiff’s injury are relevant to determining whether
property remains “unimproved.”11 And, indeed, that concession appears to be well-
founded, for the policy of relieving public entities from the duty of making property in its
natural state safe (see Milligan, supra, 24 Cal.3d at p. 833) is not furthered by relieving
them, when they do choose to improve property, of liability for making natural hazards
there more dangerous. “Since the policy on which the immunity is based is not
applicable . . . , the immunity should not be applicable.” (Milligan, supra, 24 Cal.3d at
p. 833.) A contrary interpretation would immunize a public park owner from liability for
a tree that crashes onto a restroom, a park ranger’s office or a visitor center, as long as the
tree grew in undisturbed soil some distance away as in Alana M., even if those
construction activities undermined the integrity of the tree’s root system. Or from a
rockslide that pummels a picnic or campground area, even if jackhammers or other heavy
equipment used in the construction of roads and other amenities dangerously destabilized
a nearby mountain slope. We do not think conferring immunity in those instances would
serve the Legislature’s goal.12 (See City of Santa Cruz v. Superior Court (1988)
198 Cal.App.3d 999, 1006–1007 [“the Legislature intended to preclude liability for
11
The County argues, for example, “property is not ‘improved’ for purposes of
Section 831.2 . . . unless the ‘improvements’ of which plaintiff complains caused the
event leading to injury. Changes to property that do not and cannot be considered to have
caused the injury (picnic tables) have no relevance . . . .” Likewise, it says “immunity is
not avoided by changes to unimproved property absent a showing that those changes
caused the accident.”
12
We note that beaches and bodies of water may present a different calculus,
because they are protected by section 831.2 without regard to their improved or
unimproved status. As explained in Knight, “[o]n its face the last clause
of . . . section 831.2 provides public entities with immunity, without express reference to
the improved or unimproved status of the property, for injuries caused by ‘any natural
condition of any lake, stream, bay, river or beach.’ ” (Knight, supra, 4 Cal.App.4th at
p. 927, first italics added.) The statute’s wording “vitiate[s] the ‘unimproved’
requirement as applied to public streams, bays, rivers [citation], and beaches.” (Id. at
p. 928; accord, Morin, supra, 215 Cal.App.3d at p. 189.)

18
unimproved natural conditions unless the public entity engaged in conduct which actively
increased the degree of dangerousness of a natural condition”].)
We express no opinion, however, as to whether proof of a causal link is merely
sufficient to defeat immunity or, as Alana M. held, necessary. Zachary contends proof of
a causal connection between improvements and the accident is necessary to establish that
property is improved and thus accepts the burden of having to prove this. Therefore, for
purposes here, we will assume without deciding that proof that human conduct or
improvements created, contributed to, or exacerbated the dangerousness of a natural
condition is not only a sufficient but necessary, additional element of establishing that
property is “improved.” (See Alana M., supra, 245 Cal.App.4th at p. 1489.)
In this case, a trier of fact could conclude that man-made physical changes in the
vicinity of the accident site contributed to the tree’s dangerousness and thus were
causally linked to its falling. Unlike in Alana M., Zachary introduced two expert
declarations, those of Leggitt and Downer, that, as described above, detailed the negative
impacts of construction activity on the tree’s health that made the tree more susceptible to
developing the Armillaria infection that ultimately caused it to fall.13 For the first time in
its reply brief, the County argues there is no foundation for those experts’ statements
about the historical facts concerning the construction activity that was undertaken when
the campground was built. But, unlike in the authority the County cites (where the
question was not even at issue on appeal) (see City of Santa Cruz, supra, 198 Cal.App.3d

13
We limit our analysis to evidence of physical impacts that did not result
exclusively from normal use of the campground for its intended recreational purpose. On
this point, we agree with the County that mere public use of property cannot render it
“improved” so as to defeat immunity, because otherwise the statute’s purpose would be
thwarted. (See Alana M., supra, 245 Cal.App.4th at pp. 1491–1492; cf. Schooler v. State
of California, supra, 85 Cal.App.4th at pp. 1009–1011 [public entity held immune from
liability for bluff erosion notwithstanding contributing impact from pedestrian traffic]
[construing § 831.25].)

19
at pp. 1004), the County made no such objections below or in its opening brief to this
court, and therefore has waived them.14 (See Code Civ. Proc., § 437c, subd. (d).)
In short, in this case there is evidence that artificial improvements or human
conduct “weakened the tree and made it more likely to fail.” (See Alana M., supra,
245 Cal.App.4th at p. 1491.) Accordingly, every element of Alana M. was satisfied and
the trial court properly denied summary judgment for the County.
At bottom, although the majority of courts before us have, on other facts, held
section 831.2 applicable as a matter of law, this case, on this record, presents exactly the
situation envisioned by the lead drafter of the Government Claims Act, Professor Arvo
Van Alstyne. (See Meddock, supra, 220 Cal.App.4th at p. 179.) According to Professor
Van Alstyne, “[t]he distinction between the ‘developed’ land and the ‘undeveloped’
sectors of a park might well be difficult to identify in terms of boundary lines on a map,
and might have to be treated as a question of fact . . . .” (Van Alstyne, A Study Relating
to Sovereign Immunity (Jan. 1963) 5 Cal. Law Revision Com. Rep. (1963) pp. 495–496.)
The very first reported case to construe the statute contemplated that possibility too. (See
Rendak, supra, 18 Cal.App.3d at pp. 288–289 [acknowledging there may be cases
presenting a jury triable question of fact “as to whether the unimproved danger area is
‘within and can be said to be a part of the improved area’ and thus outside the immunity
extended by section 831.2”].) This is such a case.

14
At oral argument, the County asserted that it did object in the trial court to the
experts’ purported lack of foundation, but its briefing in this court does not cite anything
in the record reflecting such an objection and we can find none. Zachary’s counsel
asserted at oral argument that there was no such objection, the register of actions does not
show that the County filed any written objections to Zachary’s evidence with its reply
papers, and no such objection was made at the hearing.

20
 DISPOSITION
The petition for writ of mandate and/or prohibition is denied. The stay of trial
court proceedings this court entered on February 4, 2016, as between plaintiff Zachary
Rowe and defendant County of San Mateo is hereby lifted. This decision shall become
final 30 days after its filing.

21
 APPENDIX
Figure 1

22
Figure 2

23
 STEWART, J.

We concur.

KLINE, P.J.

RICHMAN, J.

County of San Mateo v. Superior Court (A146077)

24
Trial Court: San Mateo County Superior Court

Trial Judge: Hon. Steven L. Dylina

Counsel:

Ropers, Majeski, Kohn & Bentley, Susan H. Handelman, Dennis J. Ward, Terry
Anastassiou for Defendant and Petitioner.

No appearance for Respondent.

Law Office of Gerald Clausen, Gerald Clausen; Rouda, Feder, Tietjen & McGuinn,
Timothy G. Tietjen for Real Party in Interest.

25