Page 58 - Archaeology - October 2017

LETTER FROM CALIFORNIA

Northern California’s Quiroste Valley today is largely overgrown, but early Spanish accounts describe a much more diverse
landscape that was carefully tended to by the Quiroste people.

California, Berkeley, archaeologist Kent take about 100 years to fully recover these expectations about natural fire
Lightfoot, one of the project’s directors. from a fire. The first plants to regrow cycles and the succession of plant
“First and foremost we wanted to are grasses and herbaceous plants. But species, the team hypothesized that
know if we could even identify the grasslands are disturbance-dependent they could differentiate between the
general pattern of human-made fires communities, meaning they can only general pattern of anthropogenic fires
in the archaeological record. Then, persist with regular grazing, tillage, and that of natural ones in the archae-
if so, we wanted to know when they or burning that removes encroaching ological record. “If people frequently
started, how widespread the practice woody plants. Given no further dis- burned the landscape in the past,” says
was, and what its impact on the local turbance, grasses don’t last long, and Lightfoot, “we would expect to find
ecosystem was.” Identifying fires from within about 20 to 30 years most of archaeobotanical and faunal remains
the ancient past is difficult enough, but the grassland is choked out by coyote that reflect widespread grasslands and
differentiating natural ones caused by brush and poison oak scrublands. fire-adapted trees.”
lightning strikes from those deliberately Within a century, the vegetation Between 2007 and 2009, the
set posed a serious problem for the reaches a mature stage, with most team, which includes members of
researchers. Underlying the challenge areas covered by scrublands and mixed the Amah Mutsun Tribal Band, who
was the fact that some scholars have conifer forests, and once again the trace their ancestry to the Quiroste,
argued that prescribed burns might not landscape becomes fuel for wildfires. systematically surveyed the site of the
have been as widespread in the ancient This fire ecology research suggests large village first described by Crespi
past as they had become when the that anthropogenic, or human-made, in 1769. Low-impact magnetometry
Spanish first arrived in California. fires would create a landscape domi- helped them pinpoint potential fire
As a first step, the team studied nated by open, prairie-like vegetation, pits and other human-made features
how ecosystems on the central Califor- while those fires occurring naturally in the ground, which they uncovered
nia coast have reacted to fires caused would result in a landscape of shrubs in a series of small excavation units.
by lightning in the recent past. Eco- and conifer forests, such as the one in Under the direction of University of
systems similar to the Quiroste Valley the present-day Quiroste Valley. Using California, Berkeley, archaeologist Rob

56 ARCHAEOLOGY • September/October 2017