THE TREE OF LIFE: DESERT RECLAMATION AT PAPAGO PARK (ARIZONA)
Moira Bateman Beeman
THE SITE
This desert reclamation project is located on the eastern edge of
Phoenix Arizona, at the gateway to the 2,000 acre Papago Park. The following
description is telling of the park's historic character, it is from Birds of the
Papago Saguaro National Monument, published in 1920: It is a rolling mesa, of
gravely or rocky soil, traversed by a ridge of hills, rising 200 or 300 feet
above the level of the surrounding desert. The plant growth is typical sparse
desert vegetation, such as occurs over vast stretches of southern Arizona.
Giant cactus is evenly, though not thickly, distributed over the whole area.
Everywhere there are clumps of "cholla" cactus, locally known as "jumping
cactus", a peculiarly diabolical sort whose thorns penetrate at the gentlest
touch.... Here and there are leafless palo verdes, or clumps of atriplex, and in
the sandy washes thickets of cat-claw or scrubby mesquite. The most generally
prevalent plant is the creosote bush (Covillea), small, rounded bushes of dark
green hue, scattered quite uniformly over even the most unprepossessing
sections. Many gravely ridges are grown up with this plant to the exclusion of
practically everything else. Along the canal which crosses the Monument,
seepage of water has produced limited growths of arrow weed and tules.
Papago Park was once the Papago Saguaro National Monument, because of the
saguaro cacti (Carnegiea gigantea) which grew there. A dramatic decrease in
these cacti resulted in the title being removed. The park's natural systems
have degraded since the description sited above was written, possibly because of
high recreational use by people (the area was a popular picnicking site for
Phoenix residents) combined with a warming trend since the 19th century. In
Saguaro National Monument, Arizona it is suggested that the warming trend could
be a direct cause of a decrease in the number of nurse plants which shelter the
saguaro during its long infancy. As a result of these changes, the plant and
animal diversity were greatly decreased. The fox population declined to zero,
which allowed the rabbit population to grow rapidly. By 1990 there were so many
rabbits in the park that they had eaten and killed most of the saguaro and other
cacti. At that time, all individual plants of the remnant saguaro population
were over fifty years old; no new saguaros had successfully established in the
park since 1950. Other populations absent from the park were the cholla cactus
(Opuntia sp.) population which was lost in the 1930s, and the bursage population
which was lost in the 1940s. Bursage had been one of the important nurse plants
for seedlings and insects.
At the gateway to Papago Park, the site of the Tree of Life is only about 2
acres in size. It is situated at the southwest corner of a busy highway
crossroads between the cities of Phoenix and Scottsdale. The site's natural
drainage or 'wash' was interrupted by the highway, and valuable water flow was
diverted by the pavement.
WHO AND WHY
In 1990 a design competition was held by the cities of Phoenix and
Scottsdale, Arizona to design a gateway for Papago Park and a boundary marker
between these two cities. The project was initiated by the Phoenix Arts
Commission and the Scottsdale Cultural Council. Funding was provided by the City
of Phoenix Parks Department, the Street Transportation Department Percent for
Art funds and Artscape (the public art program for the city of Scottsdale). The
project was administered by the Phoenix Arts Commission.
New York City artist Jody Pinto and a landscape architect knowledgeable in
desert ecology, Steve Martino, won the competition with their joint submission,
now known as the Tree of Life. From the beginning, the two designers were
interested in turning the art piece into a self-sustaining desert reclamation or
restoration. Jody Pinto expressed a hope in Sculpting with the Environment - A
Natural Dialogue, that the Tree of Life project would be the first step in a
reclamation of the whole of Papago Park, to restore it to the state when it had
the title as the Papago Saguaro National Monument.
THE RECLAMATION PROCESS
The reclamation project is an art piece. Jody Pinto
writes in Sculpting with the Environment - A Natural Dialogue, that the project
is meant to "bring new growth and life to the park" and that "The crop on these
terraces is meant to be desert life". The art piece/reclamation project is a
working water harvesting rill and terrace system in the form of a tree. In the
desert, the lack of water is a significant limiting factor in plant growth, this
piece collects and brings storm water to the desert plants. The water
collection system is based on the ancient water harvesting processes used in the
region across the span of seven civilizations, starting with the Hohokom people.
In order to take into account the larger context of the Tree of Life project,
the designers developed a larger master plan for the management of Papago Park.
The plan included controlling the rabbit population and reassessing land use
(especially the portioning of recreation facilities). This master plan was
important, it seems likely yet unclear that it was implemented. The issue of
rabbit population management may have been a touchy subject, yet if not
addressed, the Tree of Life could have become a big feed lot for that
population.
The Tree of Life reclamation incorporated interventions in terrain, hydrology
and vegetation. The terrain intervention included recontouring to help channel
roadside water to the main rill, and the imprinting of terrain with the rill and
terrace system. Intervention in the hydrology of the site was clearly executed
by the channeling of water ways through the ancient water control system of rill
and terrace. Vegetation intervention included taking existing plants off the
site during construction, nurserying them, and then replacing them. New
plantings of cacti were used, these were taken from a nearby road construction
project. Seeding of a mix of indigenous species was also attempted on the
terraces. Unfortunately, a planting and seeding list was unavailable.
Photographs of established plants on site include: cat claw (Acacia greggii),
ocotillo (Fouquieria splendens), pricklypear (Opuntina phaeacantha), cholla
cactus (Opuntia sp.), paloverde (Parkinsonia microphylla), thistle sage (Salvia
columbariae). There do not seem to be any saguaro (Carnegiea gigantea) on the
site.
ASSESSMENT OF SUCCESS
In Jody Pinto's essay on this project in Sculpting with
the Environment - A Natural Dialogue, the assessment of the success of the
project is based primarily on its cultural impact on the Phoenix community.
Specifically, as a site for solstitial alignment celebrations, and as a final
destination for a candlelight vigil in remembrance of people lost to AIDS. This
cultural success could be in opposition to the site's continued ecological
success. There is no designated path system through the site and soil
compaction from trampling could impede the successful growth of seedlings and
other delicate plants.
The projects ecological success is assessed by artist Jody Pinto by the
presentation of a photograph of a flowering ocotillo (Fouquieria splendens) on
one of the terraces, as well as aerial photographs from the first year after
completion (1992) and the second year after completion (1993). These sequential
photographs show a marked increase in the number of plants growing on the
terraces, although the designers give no written quantitative analysis of the
vegetation.
By counting the individual plants in the photographs, I have found that the 1992
photograph shows approximately 45 plants, and the 1993 photograph shows over 600
plants. The plants in the photograph from 1993 seem to be following the pattern
of the imprinting, or the rill and terrace system, suggesting that the
additional growth was a direct result of the storm water retention and
management. This, along with photographs of water being held in the terraces,
shows that the water irrigation system works on a mechanical level. Water is
successfully collected and distributed to the seven desert terraces where it can
be taken up by plant roots.
In order to understand the success of this project, it would be crucial to know
what reference desert community is being pursued. However, the reference
community is not clear. The highway interrupts a wash here, and it may be that
a wetter 'wash' area's hydrology is being replicated with the terrace and rill
system. However, there is no reference to replicating a wash area's more
luxuriant vegetation, or conversely, to pursuing a desert scrub community. In
fact, there is no technical discussion of the plan for vegetation. Some
quantitative analysis would be helpful in assessing the success of this
reclamation project. Information on plant and animal species composition, counts
and dispersal would be beneficial. These measurements should be taken at
regular intervals before, during and after the completion of the project. These
species counts and their spacing could then be compared to a reference desert
community. The plant and animal communities in the desert are varied and
intricate, and the designers of the Tree of Life do not attempt to discuss these
matters in their description of the project.
An obvious question then arises when examining this project. Why do native
desert plants need to be "farmed" in the desert? Could it be related to the
idea that there has been a decrease in rainfall over the last 100 years?
Shouldn't the existing, dry regime be appropriate to sustain the growth of
plants of the desert? It may be that the goal of this project was not really to
restore the desert exactly as it would have been.... but to reclaim this piece
of desert as a hyper-desert-garden. Plants would grow more vigorously and more
closely spaced than they would in the same site without the altered hydrology.
This may be desirable and appropriate here because this project is a piece of
art, but it might not be appropriate for a project that represented itself as
more "natural". Also, the logistics of this type of farming may be possible at
this 2 acre scale, but I doubt that it could be done on the scale of the whole
2000 acres of Papago Park. A rill and terrace system is obviously not the text
book answer for restoration or reclamation of desert communities, but seems
appropriate for this scale, site and program.
It is difficult for me to assess this art piece/reclamation project on the bases
of ecology alone. I do feel, however, that the scientific approach is necessary
when an art piece purports to be a reclamation. The designers should clearly
state what the project is, and what the project is not. These designers want
their project to have a real ecological impact, but they do not tend to that
matter adequately. As a reclamation, I believe that this project is a success,
on its own terms and on its own scale. This piece is also a success because it
is didactic and poetic, and seems to communicate meaning to the community of
people in the Phoenix area.
BIBLIOGRAPHY:
"The National Park System, Western United States, An Invitation" (map) Revised
1961, United States Department of the Interior, National Park Service
Hamilton, Frances L., The Desert Garden, Native Plants of Phoenix and Vicinity,
1933
Oakes, Baile, Sculpting with the Environment - A Natural Dialogue, Van Nostrand
Reinhold, 1995
Shelton, Napier, Saguaro National Monument, Arizona, National Park Service, U.S.
Department of the Interior, 1972
Swarth, H.S., Birds of the Papago Saguaro National Monument and the Neighboring
Region Arizona, Washington Government Printing Office, 1920
U.S. Department of the Interior Bureau of Land Management, Arizona, Phoenix,
Final Wilderness Environmental Impact Statement, 1987
U.S. Department of the Interior Bureau of Land Management, Arizona, Arizona
Wilderness Land Tenure Adjustment Plan, 1992
U.S. Department of the Interior Bureau of Land Management, Arizona, Lower Gila
South Resource Management Plan Environmental Impact Statement Phoenix District,
Arizona, Final, 1985
U.S. Department of the Interior/National Park Service, Saguaro National Monument
/ Arizona, 1988
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