The first thing you'll notice at Petrified Forest National Park are the dozens of logs lying atop hills as if on display, many of them pointing in the same direction. Closer up you can see the colors in the wood--reds, greens, yellows, blues, and purples, all of them rich and moist-looking like wet paint. The colors might tempt you to touch the wood, and if you do you'll find that it isn't wood at all, but cold, hard stone.
About 225 million years ago these petrified trees were enormous conifers growing in a tropical forest. Floods swept them into large rivers, tearing off their branches in the process. Eventually the trees bottomed out in the shallow waters of the floodplain, where silt, mud, and volcanic ash buried them. Because almost no oxygen could reach the entombed trunks, they were slow to decay. Silica from the ash gradually permeated the trunks, replacing or filling the wood's cells before eventually leaving quartz in its place. Minerals such as iron and manganese streaked the quartz with colors. The end result: The wood became beautiful rock.
Recognizing the financial value of this rock, early settlers began shipping it out on East Coast-bound trains. When the residents of the Territory of Arizona realized that the "wood" might soon be gone, they petitioned Congress to protect the "forests." Using the Antiquities Act, Pres. Theodore Roosevelt created Petrified Forest National Monument in 1906, and Congress designated it a national park in 1962.
The same sediments that entombed the trees buried other plants and animals, preserving them as fossils as well. Erosion has exposed these clays and sandstones, collectively known as the Chinle Formation. With little or no vegetation to hold them in place, these sediments erode quickly and unevenly, forming mesas, buttes, and furrowed, conical badlands, unearthing thousands of fossils, including bones from some of the most remarkable creatures ever to inhabit the earth. In addition to the 225-million-year-old fossils, there is evidence that the Ancestral Puebloans (also known as Anasazi), ancestors of the modern Pueblo tribes, once occupied this area. Evidence of other human occupation dates from 10,000 years ago.
Even without these wonders, it would be worth coming here to see the rich red, gray, and maroon colors of the Painted Desert. Shaped like a tusk (with the wider end near Cameron, Ariz.), the desert spans from near Holbrook in the south to the Hopi mesas in the northeast to near the Grand Canyon in the west--far beyond the boundaries of the park. Its seemingly barren landscape is home to a rich diversity of plant and animal life: desert grasses; wildflowers, including Indian paintbrush and globemallow; juniper and other trees; mammals, including pronghorns, cottontails, and porcupines; reptiles, including collared lizards and western rattlesnakes; and birds, the most prominent being the raven.
