Redwoods Regrow After Fires

Bole Survival and Basal Sprouting of Redwood and Associated Species One Year after Wildfire

One year after a wildfire, burnt redwoods regrow foliage. Photo by Benjamin S. Ramage
One year after a wildfire, burnt redwoods regrow foliage. Photo by Benjamin S. Ramage

In the past 70 to 80 years, most fires in California’s coast redwood forests were prevented or suppressed. But in 2008, more than 2,000 fires ignited forests in Northern and Central California during a single summertime lightning storm. Overwhelmed by conflagrations in drier areas, firefighters allowed many of fires in coast redwood forests to burn.

It was the perfect opportunity for researchers at the University of California, Berkeley, to study how the balance of two species—redwoods and their common competitor, tanoaks—was affected by fire. Did fires give one species an edge over the other? To find out, researchers scrutinized burned and unburned forests at four sites: one in Big Sur, one near Santa Cruz and two in Mendocino County. They examined both trees’ abilities to survive fires of varying severity and reproduce by sprouting.

Both species proved themselves highly resistant to fire. But the redwood was nearly indestructible. “One year later, even large trees where all the foliage was scorched off were covered with a light green fuzz of new foliage,” said Berkeley Ecologist Benjamin S. Ramage, who led the research project. “Of trees over 1.5 feet in diameter, maybe only one redwood out of a hundred was killed.”

Tanoaks proved slightly better than redwoods at sprouting after the fires. Ramage saw many 4- to 5-foot-tall tanoak sprouts forming dense clumps around the trunk after only one year. But tanoaks also sprout in forests that haven’t burned, while redwoods sprout much more vigorously after a fire. So, once again, fires gave redwoods a relative advantage.

In addition to providing valuable data about the effects of fire in California’s coast redwood forests, the study also may guide the decisions of land managers in ways that will depend upon their objectives. “If you want more tanoaks [whose acorns provide food for wildlife], it’s probably better to suppress fires,” Ramage said. “If you want more redwoods, it’s probably better to utilize fires.”

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