We sampled fire and forest history in Zion National Park in
August 2016 to provide
data for the Park's Fire Management Plan. What a terrific
place to sample fire history! Lots of old trees and stumps,
and of course a beautiful place to spend a couple of weeks. We concentrated on ponderosa pine forests in
upland areas on the East Rim and Horse Pasture Plateau and
Pine Valley on the West Rim. Much of the Park's prescribed
fire program has been focused on these landscapes. I used similar methods as in
past studies (e.g.,
Brown et al. 2008)
in which we used an n-tree density-adapted plot design to characterize age and forest structure in
randomly located plots. We also sampled remnant (only
stumps and logs) fire-scarred trees wherever we could find them.
Another goal for the study
was to collect as much data as we could from the old stumps.
Upland forests on both east and west sides of the main Canyon were heavily
harvested in the late 1800s and early 1900s, and stumps are
rapidly being lost as the Park is reintroducing fire back to
these areas. In the
following photos you can see locations where the
Park has burned in the last 20 years or so. We
ended up with a total of 28 plots, about 850 trees
This report describes some of the vegetation
structures we found, plus an overnight backpack I did on the
West Rim Trail.
One of the old fire-scarred stumps
we targeted for sampling.
A closeup of the fire scars on the "wing" of the
stump. They're often fragile but we're able to get a
Zach using the power borer for coring trees, speeds
things up considerably. Also note that Jacki
is checking the borer at the base of the tree; we
tried to sample at ~10cm hts. Note the bole scorch.
Cutting an old stump with a cat-face near plot P6.
These were exactly what we were looking for but a
lot of the area had been burned and stumps were gone for the
This is not one of our cuts! This was done by Madany
in a study back in 1980. He only took cuts on living trees,
did not crossdate. We found several of his trees.
Check closely on the photo
at how the tree is recovering over the cut surface;
they are highly resilient.
Why we have to get the stumps before fire is
reintroduced; buried in the manzanita, this one will
be completely gone after the stand has been
The Park has had an active prescribed fire program
for several years and much of the upland landscape
has seen at least one
and in some cases two burns in recent years. Overall the program has had good results. In many
of the pine stands the oak cover is at most about
0.5m in height, lower branches on the pines have
been reduced and canopy base heights raised
considerably, and openings (in some cases quite
large) have been punched into the landscape.
Bole scorch of 1-3 m was present on trees in almost
all of our burned plots. Unfortunately for our
purposes the fires also considerably
reduced the presence of stumps and logs. In
many plots, we could see holes where stumps had been
but they were completely gone. The best
records we found were in unburned stands
north of Sawmill Spring on HPP and the ridge above
Stave Spring on the East Rim. Stumps were
highly decayed but we were able to get some good
An example of fire effects
from recent burning. Lots of dead and usually down
stems, but some surviving trees across the
landscape. Note the shrub cover, mainly Gambel oak (Quercus
gambelii) and greenleaf manzanita (Arctostaphylos
At the end of our two weeks of sampling, I had the
opportunity to do a 13-mile overnight backpack down HPP on the West
Rim Trail, mainly to see the full extent of
ponderosa pine forest in this area. I left the
trailhead about 4pm after our last day of sampling.
Jacki and Zach dropped off my truck the next day at
the Zion Fire Cache; I got down around noon.
There are nine designated campsites on the trail and I camped at no. 6. It
was really great to have a chance to hike the full
Plateau; there are some beautiful ponderosa pine
stands along the trail, and almost all have seen some
level of recent fire. There also are some very
extensive areas of pine mortality, with the oak or manzanita
taking over completely. And of course, as one hikes
down the Plateau the canyons and slickrock become more and more
lovely! At the very end of the Plateau the world
drops away. The last 5 miles drop into the main
Canyon, across Navajo sandstone slickrock and
cliffside trail ledges, piñon-juniper woodland replaces ponderosa-oak, and
canyon wrens start their musical calls. The trail
continues to Angel's Landing and it
suddenly becomes packed with tourists! The
last three miles involve passing the masses; great
to see them hiking up to the Landing but oh what a
contrast to the Plateau (I didn't see another person up
on the Rim).
This next sequence of photos
is views of vegetation while hiking down the West Rim Trail.
A fairly typical view past Sawmill Spring. A lot of
our lower plots looked like this; open stands with very low oak cover (<1m
ht); note also that lower branches on the ponderosa
have been killed, raising the canopy base heights.
These stands look very good, and should be very
resilient to future wildfires.
Another view just south of Sawmill Spring. Note also
the bole scorch; not as evident in these two photos
but it was very present in almost all plots. Note again the shrub cover; to the
right in the photo it's taller where there was also
greater mortality in the overstory.
Heading down the West Rim Trail the Canyons and slickrock
start showing up well, still with scattered ponderosa stands
and individual trees.
Potato Hollow from the south; the trail comes into the
through the canyon in the middle distance, crosses
through the scattered trees right below this view (you can barely see it right below in the trees),
and then climbs back up on the ridge.
A very lovely little valley. There are two campsites
(7 & 8) in the Hollow, one you can see in the
uppermost pine trees in left center of the photo
(i.e., nice spot, but everyone above can see your
Another view along the trail. Scattered
living and remnant pine with old dead oak stems (killed in
recent prescribed fires) that likely date back
to the last historical fire (preliminary data on the rim above and on
the East Rim both show that was in 1879) and lots and lots
of new shrubs coming in. But also look at that lovely meadow in the bottom!
I camped in that stand of ponderosa
on the far hillside (camp 6).
Next morning at camp 6. I pulled my tent down already
Moons Design Deschutes Plus;
I highly recommend it); it
rained some the night before. This was only my
second trip with my new backpacking setup, worked
like a charm. BTW, I also highly recommend Mountain House
beef stroganoff, that really hit the spot for supper! Note the chair; my base pack weight is under 12 lbs
and that includes both a camp chair (Alite Designs
Mayfly; 1.53 lbs) and a tripod for my camera (Sirui
T-025X; 1.90 lbs). I know the true ultralighters
will give me shit about those two, but I have to
have a tripod for shooting HDRs and that chair sure
makes sitting near the ground a hell of a lot
easier for us old folks!
Sunrise and ponderosa the next morning, just before
hitting the trail.
Early morning view back towards Lava Point (right in
the middle of the photo). Camp 6 is in the stand of
pine to right.
Actually sunset the night before.
stand of older trees along the trail, just before it
drops off into the canyon. Camps 3 and 4 were not
far to the south from this point.
Finally, I just wanted to say thank you to a great
crew! Me, Chris, Lionel, Jacki, and Zach. Fun trip,
only one major breakdown (that damn latch on the
power borer head; I think I have a fix that a local
machine shop is working on for me), and we got a lot accomplished.
Let's do it again sometime soon...