By Betsy Herbert
Santa Cruz Sentinel
Posted: 12/19/13, 12:00 AM PST
When the subject is coast redwoods, people seem to come out of the woodwork to hear a talk, especially when an expert is doing the talking.
On Dec. 10, Dr. Will Russell drew some 125 folks to hear his talk, "Logging, Fire, and the Recovery of Old-growth Coast Redwoods," at Cubberley Community Center in Palo Alto. The Committee for Green Foothills sponsored the event.
Russell, associate professor of environmental studies at San Jose State, quickly took aim at three common misconceptions about redwoods. He and his research team investigate how redwood forests naturally regenerate after logging and fire.
"The first myth," according to Russell, "is that young managed redwood forests sequester carbon faster than old-growth redwood forests." The audience seemed intrigued, as if they had heard this claim before.
Until recently, scientists thought that old-growth redwood forests eventually just stopped growing and started slowly decaying. But a 2008 study published in the journal Nature found that old-growth forests can indeed continue to grow and accumulate carbon.
Results of recent research by the Redwoods and Climate Change Initiative, sponsored by Save the Redwoods League, are even more dramatic. After measuring tree growth and carbon sequestration throughout the entire range of old-growth redwood forests, these scientists concluded, "Ancient redwood forests store at least three times more carbon above ground than any other forests on earth," and "the rate of sequestration continues to increase with age of redwood trees."
Russell used this recent research to shatter the myth that young forests store carbon faster than old forests.
The second myth, he said, is that redwood forests need to be thinned to reduce fire hazard.
"It's not true," Russell said, explaining that unusual characteristics of redwoods need to be considered when managing them to address fire.
For example, redwoods sprout when they are cut or scarred, while most other trees used for lumber don't have this ability. When redwoods are thinned, the resulting sprouts around the cut stumps actually create fire hazard, Russell said, because the sprouts form a brushy mass that increases fuel on the forest floor.
Redwoods are also unusual because of their thick bark, which makes larger redwoods extremely resistant to fire. According to Russell's documentation, the only redwood trees killed by the Lockheed and Martin fires of the last decade were less than 7.5 inches in diameter. The larger trees, though burned and fire-scarred, regenerated by sprouting along their trunks.
Russell emphasized it's unwise to take a one-size-fits-all approach toward managing forests. For example, while it might be a good idea to thin pine forests in the Tahoe Basin to reduce fire hazard, pine forests are different from coast redwoods. Pines don't sprout when cut and they don't have fire-resistant bark.
To dispel the third myth -- that thinning redwood forests accelerates recovery of old-growth -- Russell discussed his own recent research, which was inspired by his boyhood experience of observing clear-cut forests in Mendocino County.
Some forest managers advocate thinning such logged-over forests to more quickly move the forest toward old-growth. Russell explained that while thinning forests allows the remaining trees to grow bigger, old-growth redwood forests are very complex, and much more than just big trees.
Russell's research analyzes how coast redwoods regenerate themselves. The research shows that different old-growth characteristics appear at different stages when forests naturally regenerate after being clear-cut. Yet, even after 100 years, some old-growth characteristics are still absent, such as the return of key native redwood understory plants.
"Restoration of redwood forests should focus on the soil and this understory recovery," he said.