Petrified Forest National Park

Petrified Forest National Park is a national park of the United States in Navajo and Apache counties in northeastern Arizona. Named for its large deposits of petrified wood, the park covers about , encompassing semi-desert shrub steppe as well as highly eroded and colorful badlands. The park's headquarters is about east of Holbrook along Interstate 40 (I-40), which parallels the BNSF Railway's Southern Transcon, the Puerco River, and historic U.S. Route 66, all crossing the park roughly east–west. The site, the northern part of which extends into the Painted Desert, was declared a national monument in 1906 and a national park in 1962. The park received 644,922 recreational visitors in 2018.

Averaging about in elevation, the park has a dry windy climate with temperatures that vary from summer highs of about to winter lows well below freezing. More than 400 species of plants, dominated by grasses such as bunchgrass, blue grama, and sacaton, are found in the park. Fauna include larger animals such as pronghorns, coyotes, and bobcats; many smaller animals, such as deer mice, snakes, lizards, and seven kinds of amphibians; and more than 200 species of birds, some of which are permanent residents and many of which are migratory. About one third of the park is designated wilderness—.

The Petrified Forest is known for its fossils, especially fallen trees that lived in the Late Triassic Epoch, about 225 million years ago. The sediments containing the fossil logs are part of the widespread and colorful Chinle Formation, from which the Painted Desert gets its name. Beginning about 60 million years ago, the Colorado Plateau, of which the park is part, was pushed upward by tectonic forces and exposed to increased erosion. All of the park's rock layers above the Chinle, except geologically recent ones found in parts of the park, have been removed by wind and water. In addition to petrified logs, fossils found in the park have included Late Triassic ferns, cycads, ginkgoes, and many other plants as well as fauna including giant reptiles called phytosaurs, large amphibians, and early dinosaurs. Paleontologists have been unearthing and studying the park's fossils since the early 20th century.

The park's earliest human inhabitants arrived 13,000 years ago. These Clovis-era people are the ancestors of Native Americans. By about 2,500 years ago Ancestral Pueblo farmers were growing corn and living in subterranean pit houses in what would become the park. By one-thousand years ago Ancestral Pueblo farmers lived in above-ground, masonry dwellings called pueblos and gathered in large communal buildings called great kivas. By 1450 CE Ancestral Pueblo farmers in the Petrified Forest migrated to join rapidly growing communities on the Hopi Mesas to the northwest and the Pueblo of Zuni to the east–these locations are still home to thousands of descendant community members today. More than 1,000 archeological sites, including petroglyphs, have been discovered in the park. These ancestral places remain important to descendant communities. In the 16th century, Spanish explorers visited the area, and by the mid-19th century a U.S. team had surveyed an east–west route through the area where the park is now located and noted the petrified wood. Later, roads and a railway followed similar routes and gave rise to tourism and, before the park was protected, to large-scale removal of fossils. Theft of petrified wood remains a problem in the 21st century.

Geography

thumb|Aerial view looking south from the Navajo Reservation (foreground) across the Painted Desert, the Petrified Forest National Park, and Adamana, Arizona

thumb|Painted Desert & [[Petrified Forest National Park, from the window of a commercial flight, 2007]]

Petrified Forest National Park straddles the border between Apache County and Navajo County in northeastern Arizona. The park is about long from north to south. Its width varies from a maximum of about in the north to a minimum of about along a narrow corridor between the north and south, where the park widens again to about . An unconformity (break in the rock record) of about 200 million years occurs within the park, where erosion has removed all the rock layers above the Chinle except geologically recent ones. The Bidahochi Formation, laid down only 4 to 8 million years ago, rests directly atop the Chinle, and rocks laid down in the Jurassic, Cretaceous, and much of the Tertiary are absent. crocodile-line archosaurs, temnospondyl amphibians, lissamphibians, non-archosauromorph diapsids, and other dinosauromorphs and archosauromorphs. Dicynodonts are extremely rare despite being abundantly represented at the Placerias Quarry near St. Johns. Fossil invertebrates include freshwater snails and clams. The oldest fossil crayfish, Enoploclytia porteri, was also described from the park, although it is not considered a crayfish proper (instead placed in Erymidae).

New animal species that were first identified from localities within the current park boundaries, some of which remain known only from the park, are listed below.

{| class="wikitable"

!Clade

!Taxon

!Authority

!Publication year

|Gymnophionomorpha

|Funcusvermis gilmorei

|Kligman, Gee, Marsh, Nesbitt, Smith, Parker, & Stocker

|2023

|Allokotosauria

|Puercosuchus traverorum

|Marsh, Parker, Nesbitt, Kligman, & Stocker

|2022

|Cynodontia

|Kataigidodon venetus

|Kligman, Marsh, Sues, & Sidor

|2020

|Drepanosauromorpha

|Skybalonyx skapter

|Jenkins, Pritchard, Marsh, Kligman, Sidor & Reed

|2020

|Allokotosauria

|Trilophosaurus phasmalophos

|Kligman, Marsh, Nesbitt, Parker, Stocker

|2016

|Phytosauria

|Protome batalaria

|Stocker

|2007

|Phytosauria

|Pseudopalatus jablonskiae

|Parker & Irmis

|2006

|Allokotosauria

|Trilophosaurus dornurum

|Mueller & Parker

|2006

|Tetrapoda incertae sedis

|Kraterokheirodon colberti

|Irmis & Parker

|2005

|Reptilia incertae sedis

|Acallosuchus rectori

|Long & Murry

|1989

|Decapoda

|Enoploclytia porteri

|Miller & Ash

|1930

|Phytosauria

|Machaeroprosopus pristinus

|Mehl

|1928

Climate

According to the Köppen climate classification system, Petrified Forest National Park has a cold semi-arid climate (BSk). According to the United States Department of Agriculture, the plant hardiness zone at the Painted Desert Visitor Center is 7a with an average annual extreme minimum temperature of .

Winter winds can reach .

|source 2 = National Weather Service

History

Pre-United States

More than 1,200 archeological sites have been found inside the boundaries of Petrified Forest National Park. Evidence suggests that the earliest inhabitants of the park arrived over 12,000 years ago. Clovis and Folsom-type spear points made from petrified wood are among the earliest artifacts of Paleoindians found in the park. Between , the Archaic Period, nomadic groups established seasonal camps in the Petrified Forest from which they hunted game such as rabbits, pronghorn antelope, and deer and harvested seeds from Indian ricegrass and other wild plants. By at least and through the Basketmaker II period (–)Ancestral Puebloan farmers began to grow corn. Between population size grew rapidly. Many families built houses in the Petrified Forest and for the first time began to stay there year-round.

During the Basketmaker III period, , families occupied shallow subterranean pit structures, at first on mesas or other vantage points and later at the base of bluffs and in lowlands, where the soil was better. Settlement patterns shifted and population size grew during the Pueblo I era between 700 and 900 CE and for the first time large groups of families aggregated together and formed large villages. During this period, each household built large well-insulated subterranean residential pit structures to keep warm during the cold winter months and several adjacent above ground rooms made from stone and jacal similar to adobe—used for food storage and daily activities during the warmer months. During the early Pueblo II period () Ancestral Pueblo farmers began constructing above-ground masonry architecture (for example Agate House, a small masonry structure built from petrified wood that is open to the public) signaling a greater degree of residential permanence. During the Late Pueblo II and Early Pueblo III periods 1050–1225 local population size grew rapidly. Similar to much of the Ancestral Pueblo world, population density increased rapidly at this time and nearly 1,000 sites dating to this period have been identified in the park at a wide variety of locations—at the mouths of washes, near seeps, and on moisture-holding sand dunes.

thumb|left|alt=Images of animals, people, and geometric figures incised on the dark vertical face of a large rock|Petroglyphs pecked into desert varnish in Petrified Forest National Park

Between 1250 and 1450 CE Ancestral Pueblo families gathered into large apartment building-like masonry structures (also known as pueblos) with several hundred people living together in close quarters. These large villages were often located near important water sources. Ancestral Pueblo people constructed more than two of these large pueblos, one called Stone Axe, about east of the park, and the other at Puerco Pueblo, which overlooks the Puerco River near the middle of the park. There they built roughly 200 rooms around an open plaza. Some rooms had no windows or doors and could be entered by climbing a ladder and descending through a hole in the roof. At its peak, perhaps 200 people lived in this pueblo. Over time, however, Ancestral Pueblo families undertook migrations and joined rapidly growing towns on the Hopi Mesas in Northern Arizona and at the Pueblo of Zuni in northern New Mexico, where the descendants of the ancient Petrified Forest farmers still live today. Some researchers have argued that a persistently dry climate led to out-migration, and the last residents left Puerco Pueblo in about 1380 CE.

At Puerco Pueblo and many other sites within the park, petroglyphs—images, symbols, or designs—have been scratched, pecked, carved, or incised on rock surfaces, often on a patina known as desert varnish. Most of the petroglyphs in Petrified Forest National Park are thought to be between 650 and 2,000 years old.

From the 16th through the 18th centuries, explorers looking for routes between Spanish colonies along the Rio Grande to the southeast and other Spanish colonies on the Pacific coast to the west passed near or through the area, which they called El Desierto Pintado, the Painted Desert. However, the park's oldest Spanish inscriptions, left by descendants of the region's early Spanish colonists, date only to the late 19th century. Some of the fossil wood is returned by visitors who feel guilty about their actions, but cannot be put back into the park as it's not clear exactly where it came from. As such, park rangers place it in The Conscience Pile.

Jessee Walter Fewkes, the first archeologist to visit Puerco Ruin, predicted in the late 19th century that it would yield many artifacts. Conservationist John Muir conducted the first excavations of the ruin in 1905–06. Although he did not publish his findings, he urged the federal government to preserve Petrified Forest. Professional archeological work in the park began in the early 20th century when Walter Hough conducted excavations at Puerco Ruin and other sites.

A 2005 survey found that 447 species of flora, of which 57 species are invasive, occur in the park. Although the park is known for its fossils and eroded badlands, its main environment is semi-desert shrub steppe. Protected from development and overgrazing for many years, the park has some of the best grassland in northeastern Arizona.

The Painted Desert Visitor Center, designed by modernist architect Richard Neutra, is part of the Painted Desert Community Complex Historic District listed on the National Register of Historic Places. Eight other sites within the park are also on the National Register, including the Painted Desert Inn and associated cabins, the Agate House Pueblo, the Painted Desert Petroglyphs and Ruins Archeological District, Newspaper Rock Petroglyphs Archeological District, Puerco Ruin and Petroglyphs, the Flattop Site (an archeological site), the Twin Buttes Archeological District, and the 35th Parallel Route (also known as the Beale Camel Trail). The Painted Desert Inn was upgraded to a National Historic Landmark in 1987.

The visitor center, which is near the north entrance to the park, offers visitor information and shows a 20-minute orientation movie, "Timeless Impressions", once every half-hour. It has a bookstore, exhibits, a restaurant open from 8 a.m. to 3 p.m., a gift shop, a gas station, a post office open from 11 a.m. to 1 p.m. Monday through Friday, a postal drop box, and public restrooms. The Rainbow Forest Museum complex north of the park's south entrance offers services including information and "Timeless Impressions" showings once every half-hour. It has a bookstore, fossil exhibits, an interactive Triassic Virtual Tour, limited food service, a gift shop, and public restrooms. The Painted Desert Inn, north of the Painted Desert Visitor Center, offers visitor information. It has a bookstore, museum exhibits (including the building itself), and public restrooms. With a few exceptions such as unpaved Old Highway 66, bicycles must stay on paved roads such as the main park road and stay off trails and unpaved surfaces.

The park's seven maintained hiking trails, some paved, vary in length from less than to nearly . Pets are allowed on these trails if kept on a leash, but bicycles are not. These named trails are Painted Desert Rim, Puerco Pueblo, Blue Mesa, Crystal Forest, Giant Logs, Long Logs, and Agate House. Hikers and backpackers may also visit the park's wilderness areas. Free permits are required for overnight stays; they are issued from the Painted Desert Visitor Center, Painted Desert Inn, and Rainbow Forest Museum. Most backpackers enter the wilderness at the north end of the park, where parking and an access trail are available at Painted Desert Inn. Group camping is limited to eight people.

Rangers offer a variety of programs about the park. Regularly scheduled events include a Painted Desert Inn tour, a Triassic program at the Rainbow Forest Museum sunroom, a talk or walk along the Giant Logs Trail behind the museum, and a Puerco Pueblo guided walk. The park hosts special events related to Earth Science Week and National American Indian Heritage Month. On Saturdays from Memorial Day weekend through Labor Day at the Painted Desert Inn, artisans from the region give cultural demonstrations related to ancient peoples, intertribal relationships, and European-descent cultures. For students and teachers, the rangers offer educational materials and field-trip talks. In some years during the summer months, artists-in-residence work in the park.

References

Works cited

External links

American Southwest, National Park Service Discover Our Shared Heritage travel itinerary
Geologic map of Petrified Forest National Park, Arizona Geological Survey
Historic American Engineering Record (HAER) documentation, filed under Holbrook, Navajo County, AZ:

Geography

Climate

History

Pre-United States

See also

References

Works cited

External links