This biggest log on the Giant Logs Trail in the southern portion of Petrified Forest National Park has a diameter of 9 feet, 9 inches. Photo by Reed Parsell/Special to the Review-Journal The Blue Mesa trail treats visitors to Petrified Forest National Park to an insider's look at some colorful formations. Photo by Reed Parsell/Special to the Review-Journal

By REED PARSELL

special to the review-journal

What took 225 million years to create and is being destroyed by humans at the breakneck pace of a couple hundred years?

The planet's oil supply, you say? Certainly that's a good guess, and probably a correct one. However, what I had in mind are the wonders left to be taken in at -- not taken from -- Petrified Forest National Park, about 110 miles east of Flagstaff in northern Arizona. Billed as having the world's largest collection of exposed fossil trees, the park is pillaged at the estimated rate of one ton of petrified wood per month. Some of the thieves can't live with the guilt, or parents discover their children's "souvenirs" and order confessions: The park's mail includes many letters of apology and packages of returned rocks.

Despite that depressing crime report, visiting the park is a pleasure thanks to the petrified samples that do remain and to some awesome vistas. A 28-mile road that runs between Interstate 40 to the north and Highway 180 to the south passes by all the featured attractions. Most of the petrified wood is in the park's southern section, which in my opinion makes it the place to start -- especially if you drive there from Flagstaff.

Behind the Rainbow Forest Museum, two miles past the southern entrance station, visitors walk out the back door and are treated to a jolting sight: Tree stumps and fallen trees scattered everywhere, all of them very thick, most with brown exteriors that look exactly like bark, many with exposed insides that are improbably colorful. One tree, the park's largest, somehow managed to retain much of its roots system, which flares out from the bottom like a blooming dark flower.

The man who turned to me and remarked, "What a waste of good wood!" was mistaken. The wood's been gone for a couple hundred million years. What's left, and what gives the petrified trees their hardness and bright interiors, are silica and minerals that slowly replaced the wood after fallen trees became covered with silt, sand and volcanic ash. Sometimes buried hundreds of feet underground, the compacted, petrified trees eventually were pushed back up to the surface as the earth shifted, movement that caused some of them to break into several pieces. That's why several trees behind the museum, on the 0.4-mile Giant Logs Trail, look as though they have been attacked by chainsaws.

Children might be more interested in the museum's dinosaur exhibits. On the day I visited, kids cooed over an old diorama that shows two phytosaurs engaged in a bloody battle. Phytosaurs, crocodilelike reptiles that were as long as 40 feet, are the most common fossil animal found in the park. Metoposaurs (giant amphibians), aetosaurs (10- to 15-foot-long plant-eating lizards), rauisuchians (vicious late Triassic-era predators) and therapsids (prehistoric rhinoceroses) also once called the region home.

Six miles north of the museum, Crystal Forest gives visitors another great excuse to stretch their legs over a short trail (this one's 0.8 miles long) that allows many close-up views of petrified beauties. They are scattered liberally about several small, generally light-colored sandstone hills. A few miles farther up the road, Jasper Forest once was jam-packed with petrified wood, but it was ransacked in the late 19th and early 20th centuries thanks in part to the establishment of a nearby cross-country rail line in 1882.

Although the area was declared a national monument by President Theodore Roosevelt in 1906, no rangers patrolled it for another 15 years. Jasper Forest continued to be raided; sometimes, collectors used dynamite to break up the unwieldy logs. A trail sign quotes a woman's diary describing a scavenging trip there in 1917: "Oh such a time as we did have deciding which part of the forest to leave and which part to pack out."

Fortunately, no one made off with the nearby Agate Bridge, a 100-foot-long petrified log that spans a 40-foot-wide dry creek bed. In 1917, rangers reinforced the tree by installing a supporting concrete bridge underneath it. Such aggressive preservation is a practice of the past; if discovered today, Agate Bridge would be allowed to crack and tumble at its own pace.

Continuing north, park tourists encounter Blue Mesa, whose one-mile loop trail has a steep section that will get the blood pumping; the Tepees, a modest collection of cone-shaped hills with layers in subtle blues, purples and grays; and Puerco Pueblo, ruins of a 100-room complex inhabited by American Indians from roughly 1100 to 1380. Also in that mix of central-park attractions is Newspaper Rock, where I encountered a commotion of a dozen or so people who used binoculars (two provided by the park on pedestals, the others wisely brought by the visitors) to examine the 600-some images carved 650 to 2,000 years ago on the rocks below -- images that might have represented "the news of the day," hence the site's modern nickname.

Across the Burlington Northern Santa Fe Railway line and I-40, both of which bisect the elongated, F-shaped (if you use a lot of imagination) park, the main road offers a half-dozen chances for drivers to pull off and see the Painted Desert. These badland hills and mesas erupt in earth-tone colors that are especially pronounced around sunrise and sunset, when skies are clear. The Painted Desert Inn, a National Historic Landmark that in the 1920s was a lodge and jumping-off place for guided automobile tours, was redesigned during the Depression in a rustic, Southwestern style and today contains a bare-bones museum and gift shop.

The park's northern entrance, as is the case down south, has a gift store, snack bar and visitors center that every half-hour screens a worthwhile introductory video. There's also a ranger kiosk on each end of the main road where cars can be inspected for stolen wood. Don't take the chance: Minimum fines exceed $300, and cheap petrified wood is easy to buy just outside the park's boundaries.

Petrified Forest National Park is open daily from 7 a.m. to 7 p.m. Entry is $10 per vehicle. For more information, call (928) 524-6228 or visit www.nps.gov/pefo.