Twenty miles east of Holbrook, Ariz., travelers along Interstate 40 can leave the highway and delight in a truly remarkable wonder of nature.
Allowed time, conditions and a blend of minerals, a magical transformation occurs. A tree turns into stone. Petrified Forest National Park, encompassing 50,260 acres, gained park status in 1962. Containing one of the world’s largest concentrations of petrified wood, Arizona’s national park also claims the most colorful. Found in nearly every one of the United States, this material is also encountered in dozens of countries around the world.
Generally, it takes less than 100 years to petrify wood. Preserved underground without oxygen, mineral-laden water seeps through the sediment, depositing minerals in the organic plant cells and converting them to stone.
The primary geological formation in Petrified Forest National Park is the Chinle Formation, deposited more than 200 million years ago, during an era known as the Triassic Period. This region was situated slightly north of the Equator. In that tropical climate huge coniferous trees flourished. Once they fell, massive flooding moved the logs downstream, ending up in immense logjams. Buried beneath sediment, a century later these logs would petrify.
With the movement of the earth’s crust, this region moved gradually far to the northwest, eventually to its current location in Arizona. About 60 million to 80 million years ago the Colorado Plateau began to uplift. Erosion removed rock layers, exposing the petrified forest. Plant and animal fossils as well as tons of petrified wood still lie buried below the surface.
A 28-mile drive through the park provides an opportunity to view up close the results of this magical process, named petrification. Thousands of tons of beautifully colored logs lie across grassy fields and beside low hills of Bentonite clay. A softball-sized piece weighs as much as a shot-put. Petrified wood is also extremely hard. On the Mohs’ scale of hardness it ranks at 7.8. Talc is a one, diamonds are a 10. Several trails, all paved, wind intimately through lands littered with gigantic stone logs, wonderful examples of nature’s art.
Following a brief stop at the visitor center at the north entrance, wonders of this place quickly unfold at pullouts along the paved road, overlooking a fabulously colored Painted Desert. As thunderclouds fill the horizon sky, bright sunlight washes across the valley, enhancing an already gorgeous setting. Painting a vast array of pastels, pink, red, purple, charcoal, yellow, orange and more, low hills sparkle in afternoon sun. This is Mother Nature in another of her finest hours.
Crossing a bridge, Puerco River flows a deep red color, evidence that recent heavy rains have fallen. Churning westward, the normally dry wash roils with runoff gathered foam and debris. Just beyond the bridge, Puerco Pueblo Ruins offers an opportunity to stretch legs along a short half-mile trail and visit what was once a 100-room pueblo built around 1250 A.D., inhabited by nearly 1,200 people.
Petroglyph rock art adorns trailside rocks. More extensive examples of rock art are found a short distance down the road at Newspaper Rock, where more than 650 petroglyphs have been pecked into desert varnish coated boulders.
A few miles further, the Teepees – cone-shaped formations of iron, carbon, manganese and other minerals – reach skyward in layered colors of red, blue, purple, white, black and gray.
Blue Mesa, the earliest opportunity to view petrified wood, stands at the end of a 3-mile side road. Following a brief pullout stop overlooking jumbles of stones lying at the base of steep, hiker-restricted hillsides, Blue Mesa Trail provides a chance to walk amongst fallen trees and actually touch the wonders of this national park.
Cautiously descending a steep incline, visitors walk into a small canyon, petrified wood scattered across the landscape. Short excursions off the paved trail lead into deep fissures, piles of logs heaped at the bottom. The colors are magnificent. Opening wide toward the southwest, views look into Jasper Forest, another area covered with giant logs.
This 1.5-mile loop trail meanders through badlands, visitors nearly surrounded by hills of bluish Bentonite clay. Plant fossils are found in the sedimentary layers of Blue Mesa.
With the park at an average altitude of about 5,700 feet, the steep climb returning to the top of the bluff is strenuous.
Temperatures hover near 80, blue skies enhanced by fluffy white clouds, monsoon storms building in the distance. Water puddles and considerable mud attest to recent intense rains.
Federal law prohibits the removal of petrified wood from the park. With more than 600,000 visitors annually, people taking even the smallest piece can easily result in the loss of tons of this precious element. Dozens of rock shops in the area, some even inside the park, sell petrified wood mined on private land adjacent to park boundaries. Deposits are generally found 60 to 80 feet underground.
At Crystal Forest, a one-mile trail passes easily through exquisitely colored logs. Here nearly entire trees lie exposed, sectioned as if cut by a chainsaw. As afternoon sunlight angles low, vibrant colors are enhanced.
Turned to stone primarily by silica (quartz), the beautiful colors are due to trace minerals. Iron provides the mustard, orange, reds and yellows. Blue, purple and brown are caused by manganese. Chromium and copper result in blues and greens.
Across the road to the west stands Battleship Mountain. A unique feature of this undeveloped site is the land appears as it did when the park was first created, land virtually covered in all shapes and sizes of petrified wood. As a ranger explained, most visitors don’t experience this area, with less chance of them illegally pocketing a treasure. On the western hill slopes, the site’s namesake is evident. Halfway up the slope, huge petrified wood logs poke out of sediment deposits, resembling a ship’s cannons.
Some of the park’s wilderness area is available for day-use exploration. Hiking is cross-country, offering an opportunity to experience sites seldom visited. Backcountry permits may be obtained for overnight camping in limited areas.
Behind the visitor center near the south entrance, Giant Logs Trail meanders about a half mile through a dense collection of massive logs and huge chunks of petrified wood. A park highlight – a 35-foot section dubbed “Old Faithful,” weighing an estimated 44 tons – lies trailside. Much of the main root system is even preserved.
A half-mile east, Long Logs Trail leads across open grasslands past Petrified Forest National Park’s largest concentration of trees, a fitting end to an extraordinary adventure. This 1.5-mile path passes many trees lying as they fell.
Framed by colorful badland formations, remains of still intact petrified trees provide excellent perspective to their size and of the widespread forest that dominated a tropical landscape. Stepping off their length, many reach over 80 feet. One is reported to measure 120 feet long.
Long Logs Trail intersects with Agate House Trail, leading to Agate House, constructed by Puebloan People around 1050 to 1300 A.D. This eight-room pueblo was built of petrified wood blocks and clay mortar. They used petrified wood for tools, such as knives, arrowheads and scrapers.
Few artifacts have been found, leading archeologists to surmise this location was only briefly inhabited.
Returning to the parking area, a remarkable afternoon amidst another of nature’s wonders draws to a close. Overall, a total just over 6 miles has been “hiked” along gentle trails, with a minimum of off trail adventures, an amazing time spent in Arizona’s high desert experiencing material that has undergone nothing short of a truly magical transformation.
Nearing the park’s exit gate a sign warns, “be prepared for vehicle inspection.” Yes, they are serious about not removing samples from the park.
Heading west along U.S. Highway 180 toward Holbrook, the day ends enjoying an absolutely gorgeous sunset.
For more information contact park ranges at www.nps.gov/pefo or 928-524-6228.