FLAGSTAFF, Ariz. -- Robert Auza doesn't remember exactly where or when he sliced his name into the soft, white bark of an aspen tree in Flagstaff.
He and his cousins were just boys then, exploring the hills during a lazy summer while his grandfather herded sheep.The trees remember, though. They've kept a record.
"The only reason I know they're still out there is people say, 'I saw your name or your grandfather's name,' " said Auza, now a 31-year-old Forest Service firefighter.
Auza's markings are among thousands of bark carvings done by sheepherders and their families on aspen stands in northern Arizona over the decades -- some dating back to the 1880s.
And now the U.S. Forest Service is fighting the clock to document the tree graffiti, ranging from rough self-portraits to churches and nude women, before they are wiped out by old age, pestilence, fire or vandalism. Some trees in the area have already exceeded an aspen's typical life-span of 90 to 120 years.
"They are a living record of people who don't necessarily show up in written history records," said Linda Farnsworth, a Forest Service archaeologist.
The carvings, gray and raised on white bark, document the changing demographics of sheepherders, part of what had been one of Arizona's major industries from the late 1800s to mid-1900s. Many of Flagstaff's early herders were Basque, coming from France and Spain to work, while carvings indicate that later herders came from Mexico, she said.
"I don't think we'll get to all of them, ever," she said. "In a way, it's sort of a salvage operation."
Since 1996, Farnsworth and volunteers in an Elderhostel program have documented about 2,000 tree carvings. A weeklong program trains people to sketch and photograph carvings and to log their location and tree condition, Farnsworth said.
"By the second or third day they are completely addicted," she said.
To make the best use of time, the Forest Service is targeting areas used heavily for recreation, out of fear of vandalism, and is trying to get a geographic sampling of the trees, Farnsworth said.
Although the aspens tower 60 to 80 feet, carvings remain at the level they were done. That is because the trunk grows in diameter, with most of the growth at the ends of the branches and at the top, said Jim Rolf, a forest regeneration expert with the Forest Service.
Aspen lack heavy resins of pine trees so they form corky gray cells to try to heal the scars from carvings, Rolf said. "Some people were able to carve really well, and it stayed really legible."
Auza's grandfather, Frank, was one such carver.
Frank Auza, a Basque from Spain who arrived around 1915, is an easy name to find among the trees. One carving of his name, dated July 14, 1927, marks a tree that contains nails, which Farnsworth said are remnants of tree furniture used by herders.
Other herders went beyond leaving their names. Andres Diez, for example, left his face -- on several trees.
"He liked to carve himself, we think," Farnsworth said, noting a profile of a Diez dated 1935. One tree has two faces -- one apparently a woman wearing a hat -- leaving Farnsworth to wonder if Diez brought a date to the hills.
Other carvings focus on things herders might have missed in their often solitary lives, such as the church, wine and women. "Long live the church," reads one carving, in French, next to an ornate carving of a church that wraps around one tree.
Martin Etcheberry carved his name, home country of France and a toast -- with a wine decanter and glass -- on July 21, 1932.
Years later in 1976, Raul Ornellas of Mexico added a life-size nude woman to the memory of the trees.
Farnsworth said she used to worry about what the elderly volunteers would think about the sometimes risque carvings.
"I kind of thought they might be offended by stuff like this, but I've never found anyone that is," she said, laughing.