Clemson Extension Forestry and Wildlife

Grand Natural Treasure

The common theme for most of my written works have involved some aspect of forestry associated with the southeastern wood “basket”. I was inspired on my recent family vacation to visit several National parks (Grand Canyon, Petrified Forest, Arches, Canyonland, Bryce Canyon, Coastal Reef, and Zion) across northern Arizona and southern Utah. In my opinion, the most spectacular was the expansive 1.2 million+ acre Grand Canyon National Park. Of course, all of the national parks were impressive, however one should allow for at least a full day or more to experience each of the larger parks. If the reader has not visited the Colorado Plateau parks, I strongly encourage them to begin planning and make it happen. This article should provide motivation to kindle interest to take in this our southwestern majestic natural resources! Believe me, the reader will miss a transcendent life opportunity by not slowing down from everyday life and getting out there!

Colorado Plateau Forestland

green tree growing in rocky soil
Gambel Oak in Bryce Canyon National Park. Photo credit: Stephen Peairs, Clemson University.

The forestland in northern Arizona and southern Utah (within the plateau physiographical region) is more simplistic in regards to species composition compared to our eastern forests. Elevation influences the species composition found across the park. The lowest areas, on the plateau, and up to the mountain peaks have mean elevations of 2,461 feet; 6,352 feet; and 12,600 feet; respectively (US National Park Service). Arid shrublands and grasses dominate the lowest elevations with exception of boxelder, New Mexico locust, Arizona walnut, and Fremont cottonwoods immediately adjacent to river floodplains. On the mid-plateau elevations, pinyon pine, junipers, and shrubs persist. The most prevalent abundance of tree species are found at higher elevations in montane forests primarily consisting of Ponderosa pine, Gambel oak, white fir, Engleman spruce, Douglas fir, Utah juniper, alligator juniper, Colorado pinyon, and quaking aspen.

At the highest elevations, one might observe the bristlecone pine which are one of the oldest living species on earth. These species can live for thousands of years with the oldest known tree (Prometheus), which was cut down in 1964, being 4,900 years of age. This species is also of particular importance in dendrochronology (study of tree rings) as it can be used to evaluate climatology over thousands of years.

Site index quality is low/poor for the majority of the park. Site index data (timberland productivity) was “difficult” to obtain for areas outside of sites that actually contain Ponderosa pine. Use of the NRCS Soil Survey yielded low site index values between 60 – 65 (highest values found in the area); base age 50 for Ponderosa pine and Utah juniper. Thus, these species are expected to reach heights of up to 65 feet when they are 50 years of age. Needless to say, the area has minimal potential for quality timber management given the low amount of yearly precipitation [approximately 8 inches per year (US National Park Service)].

The Wildlife

two elk grazing in a grassy field
Elk grazing in grassy forest opening in Grand Canyon National Park. Photo credit: Stephen Peairs, Clemson University.

Multiple mammals can be readily observed while enjoying the park. Small rodents, rock squirrels and cliff chipmunks, are routinely “intermingling” with park guests, especially if they think they might get a free meal. Large ruminants including pronghorn, mule deer, and elk are likely to be seen in select settings in and around the park. On rockier slopes, bighorn sheep flourish in groups. Even bison were observed on the trip and can be found in select grassland portions in the region. Predator species, including mountain lions and coyotes, also have a presence on the parks.

A lizard on the ground eating an insect
Collared lizard having an insect meal in Petrified Forest National Park. Photo credit: Stephen Peairs, Clemson University.

Reptiles are abundant on the Colorado Plateau as well. The Grand Canyon NP has 22 species of snakes, 18 lizard species, and one tortoise noted in literature (National Park Service). A couple notable species include the Western (Grand Canyon subspecies) rattlesnake, which is only found in Grand Canyon NP, and the venomous Gila Monster. There are five other species of rattlesnakes (Western (Great Basin subspecies), speckled rattlesnake, black-tailed rattlesnake, Prairie rattlesnake, and Western diamond-backed rattlesnake) found in the park itself. Other rattlesnake species also exist within the region and include the Arizona black rattlesnake, midget faded rattlesnake, sidewinder, and Mohave rattlesnake.

Various bird species can also be observed in the region. Two species, the California condor and Peregrine falcon, were nearly extinct but now thrive in the region. As of December 2022, there are a total of 561 condors with 116 located in Arizona/Utah. In particular, the Grand Canyon provides preferred habitat for these species. It is astonishing to watch these birds in the wind at lesser elevations than the viewer’s observation point!

Petrified Wood

colorful piece of wood
Petrified log piece at Petrified National Park. Photo credit: Stephen Peairs, Clemson University

The Petrified Wood NP located in Northern Arizona was once rainforest located near the equator on the southwestern edge of the supercontinent Pangaea. Most of these fossilized wood pieces are from an extinct conifer species (Araucarioxylon arizonicum). These trees lived approximately 225 million years ago. When they fell, the logs were quickly covered with sediment containing volcanic ash and organic matter. Silica from the ash was dissolved by groundwater and formed quartz crystals that replaced the organic matter. Iron oxide combined with the silica to create the varied color patterns observed today.


When one looks over the Grand Canyon Rim for the first time, an overwhelming sense of awe and grandeur touches the soul. Your minuteness is revealed as you gaze not only into the vastness of open land that stretches to both ends of your visual vantage points, but also the depth of the riverbed in the far distance (ranges from 6 – 19 miles pending hiking trail). When this moment occurs, take a deep breath, shed a tear, and stand amazed at the natural wonder. Watch the shadows of the clouds as they “dance” across the undulations of the landscape creating an ever-changing palette of color and contrast. The surreal feeling can be described as unbelievable at a minimum. My wife stated it best, “it feels like we are in a green screen image…how can this be real?”. This feeling of awe can be expected at the multiple other national parks as well. The color combinations of the hoodoo formations in Bryce Canyon, the checkerboard mountain walls of rock in Zion, the timeless (but slowly vanishing) sandstone arches/windows at Arches, etc. In all of the landscapes that I have seen, none are as impressive as those I witnessed on the national park tour. I implore the reader to follow their adventurous nature and head westward. You and your loved ones will truly be blessed and even have a new perspective on life!

Additional References

The Colorado Plateau (U.S. National Park Service)-

Great Basin Bristlecone Pine – Bryce Canyon National Park (U.S. National Park Service)-

Bryce Canyon National Park (U.S. National Park Service)-

Capitol Reef National Park (U.S. National Park Service)-

Grand Canyon National Park (U.S. National Park Service)-

Zion National Park (U.S. National Park Service)-

Petrified Forest National Park (U.S. National Park Service)-

Canyonlands National Park (U.S. National Park Service)-


Stephen Peairs, Cooperative Extension, Forestry and Wildlife Specialist

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