Team Trying to Pick Up Trail of Lost Civilizations : Excavation: Archeologists get volunteer help as they try to unearth secrets in Angeles National Forest.

Retired police Lt. Doug Collisson always loved a good mystery.

Now, deep in the Angeles National Forest, the dogged 49-year-old is on the trail of perhaps the biggest whodunit of his life--with 4,000-year-old clues.

Collisson is part of a volunteer archeological crew, snooping for the secrets of these ancient woods. The archeological team is trying to reconstruct the past, much the way Collisson once did on the homicide beat in South Los Angeles. But this time, he and other history buffs are trying to solve mysteries of antiquity:

What Native American tribes lived and died in the San Gabriel Mountains? Did they head for the mountains only in the balmy days of spring, so that they could make tents out of the blooming yucca plants and grass mats and beat the wily squirrels to the pine nuts? Or at other times of the year as well?

What did they trade to get their precious obsidian, a type of volcanic glass from the eastern Sierra that they used for knives and projectile points?

“A good crime scene. That’s what we’ve got here,” said Collisson, who lives in the east San Gabriel Valley. “Some very small clues, but eventually the whole picture will come together.”

The three-week excavation project, in the Arroyo Seco District, started May 9 and ended May 26. There are no answers yet, but four professional archeologists who led the dig will study the excavated material, which includes arrowheads, grinding stones and charred animal bones, evidence of cooking. In a related project, seven volunteers and a paid consultant returned May 22 from a nine-day hike into the remote Sheep Mountain Wilderness, where they documented gold mining sites from the 1850s and early 1900s for the first time.

Consultants will prepare reports on both sites for forest officials, who will provide the information to researchers, develop plans to protect the sites and possibly develop interpretive displays with the artifacts.

For the first time, the Angeles National Forest this year is participating in a nationwide U.S. Forest Service program called “Passport in Time,” which started in 1989 as a way to encourage public involvement and get free labor. The program allows rangers to research historic sites for which they have had neither the money nor the staff to preserve and document.

Forest archeologist Michael McIntyre said the program provides a rare opportunity to examine sites. With only two archeologists for the 694,000-acre forest, there is little time to do much except note the existence of a site with historical potential, he said.

The forest contains 400 sites that are recorded at UCLA’s Archeological Information Center, 95% of which are unexplored. Instead, the sites are left to the vagaries of weather, looters and animals, said McIntyre, who was hired in 1981 as the forest’s first archeologist.

“We try not to call any attention to it,” McIntyre said. “Leave it alone, record it and hope no one notices.”

McIntyre shakes his head at the cost of neglect. Twenty years ago, for instance, after Forest Service rangers tried to shore up a river bank, the river changed course and washed away Native American rock art in San Gabriel Canyon.

The two Passport in Time projects allow the Forest Service to begin chipping away at its backlog of historical and archeological sites.

For the Native American project, the chance to chase history drew 31 volunteers--including residents of Idaho, Arizona and Texas--to a hilly site crowded with Jeffrey Pine, sagebrush and wild rose. Some of the sunburned volunteers fell into their sleeping bags as early as 8 p.m., exhausted after a long day lugging dirt-filled buckets that turned their arms to stone and fighting off swarming gnats that dived into their eyes.

Volunteers included a certified public accountant who was born in West Germany, a yellow pages advertising representative who started the cold mornings with extra-strong coffee and a grandmother in a floppy straw hat--people who usually don’t get the chance to bite down on an excavated pea-sized chip to see if it is hard and clinks against the teeth, a test to help determine if it is bone material.

And on the 21-mile gold mine research hike, past the Bridge to Nowhere and through woods with no trails, volunteers lugged 75-pound backpacks up steep mountains, keeping their eyes open for black bears, mountain lions and rattlesnakes.

It’s all in the name of history; it certainly can’t be for the money.

The unpaid volunteers bring their own food and camping gear. Projects, which last from a week to several months, are listed in a nationally distributed catalogue that describes the site and any prerequisites for participation, such as age and hiking expertise.

So far, 230 projects have been sponsored nationwide. Among them: a Coronado National Forest project in Arizona to excavate Old Camp Rucker, a small military post that sent out Indian scouts to search for Apaches; and a Nebraska National Forest project to record 6,000-year-old prehistoric sites in the Great Plains, where researchers have already uncovered a hearth and butchered bison bone.

Along the way, volunteers have made discoveries of their own. For instance, in North Dakota, volunteers who searched for Custer’s 7th Calvary’s trail to the Little Bighorn River unexpectedly stumbled across evidence of the army’s camp sites--a piece of history that might otherwise have been lost, said Kathleen Schamel, Passport in Time coordinator in Washington.

“We have these sites, we don’t know what they are and we have to interpret them and find out how they fit into the grand scheme of our nation’s history,” Schamel said.

No federal money is earmarked for the Passport in Time project. Instead, officials from each participating national forest use funds from their cultural resources budget. For the Native American project, Angeles National Forest officials allocated about $23,000 to hire archeology firm C.A. Singer & Associates Inc. of Cambria and $15,000 for the mining expedition, led by paleontologist Steven W. Conkling of LSA Associates Inc., an Irvine-based environmental firm.

In the Angeles National Forest, archeological sites are usually discovered as part of a cursory investigation for environmental impact reports, which are state-required documents for construction projects such as roads and trails.

By law, archeological sites recorded at UCLA’s local clearinghouse are secret--disclosed only to researchers--and exempt from the Freedom of Information Act. Some, however, are opened up after excavation for interpretive displays. In popular hiking areas, sites with archeological potential are closed off but unmarked, while sites in remote areas are simply left alone.

Forest Service officials learned about the one-acre Native American site 14 years ago, by word of mouth. “People said, ‘Oh yeah, as kids we used to come up here and collect artifacts,’ ” McIntyre said.

And, a few years ago on the site, McIntyre found a granite grinding stone, called a mono , and a flat milling stone, called a metate , both of which Native Americans used to grind grain into flour for cakes, gruel and bread.

In preparation for the excavation and preservation of the Native American site, forest officials last winter made permanent changes: altering the path of a trail to avoid the site and moving some camping and equestrian facilities.