How is Armstrong Redwoods State Park recovering?
It’s a familiar theme: the larger-than-life superheroes stand together facing repeated attacks, drawing on amazing abilities to survive against all odds. Then, after regrowing limbs and regenerating entire bodies, they live nearly as long as immortals.
No, it’s not the fictional Marvel Universe. It’s happening, live, in our backyard: the saga of California’s immense coast redwoods, on display in the newly reopened Armstrong Redwoods State Natural Reserve.
In the last six years, they’ve been hammered by record drought, devastating wildfire, surging floodwater and hurricane-force winds. And now they’re healing.
“It seems impossible that a giant wooden structure could survive intense wildfire, but redwoods are incredibly resilient. They’ve evolved over tens of millions of years to survive,” Laura McLendon said.
McLendon is the director of land conservation at Sempervirens Fund, which protects and studies the sequoia forests of the Santa Cruz Mountains, including those within Big Basin Redwoods State Park, 97% of which burned in the firestorm of 2020, old-growth groves and all.
So how do coast redwoods manage to shrug off immense damage, lethal enough to kill other trees growing in the same forests?
Brendan O’Neil, senior environmental scientist at Sonoma-Mendocino Coast District California State Parks, credits their unique biology, adapted over millennia to meet the harsh challenges of their California environment.
Unlike hardwoods or giant Douglas firs, which can die outright in intense burns, redwood contains very little flammable resin or sap. In addition to a thick, fibrous, flame-resistant bark, redwoods hold relatively more water in their dense wood. Combined with their huge mass, this helps protect living tissue from heat.
Even after losing limbs and leaves, the barren charred trunk of a redwood can remarkably recover and even regrow an entirely new branch structure. The trees are equipped with specialized tissues beneath their bark, which can lay dormant for centuries but burst into rapid growth when the tree is grievously injured or stressed.
In the grey ash and aftermath of fire, redwood trees appear to be lifeless. But within several weeks, they will become covered in what looks like green fur, new sprouts pushing their way out through the blackened bark.
This epicormic growth is unique to redwoods among conifers, O’Neil said. And it lets the redwoods rapidly rebuild lost leaves and branches, which they need to make food from sunlight.
“They’re uniquely regenerative,” McLendon said. “In time, redwoods can restore their entire canopy and limbs.”
In seven to 10 years, a single tree can regrow nearly an acre or more of leaf surface.
That’s not their only special ability.
“Even when fire burns into the core of the tree, where it can smolder for as much as a year,” O’Neil said, “as long as enough of the base remains intact, the tree can survive and keep on growing.”
About the only way to kill to a redwood tree is to have such intense heat that its root system is destroyed, or so much structural loss at its base that it collapses and topples over.
In that case, even if the tree is lost, as long as roots have survived, they can resprout entirely new trees from the stump’s base.
Damage at Armstrong
Out on the fire-swept slopes of Armstrong and Austin Creek parks, O’Neil has been hard at work the past year assessing and dealing with the damage, alongside State Park staff and volunteers and staff from Stewards of the Redwoods.
Thousands of dead fir, madrone, bay laurel and tanbark oak trees have had to be removed or cut down, to reduce hazards in the burned zones.
Although no official survey has been completed yet, O’Neil estimated that somewhere between 2 - 5% of the redwoods in Armstrong / Austin Creek were killed in the Walbridge fire in 2020. While that doesn’t seem like a lot, in relation to the small number of sequoias remaining in the state, it’s a significant loss, he said.
The giants grove on the valley floor at Armstrong is now open to a relieved public, but the upland Pool Ridge and East Ridge trails on either side of the canyon are not.
Fire leaves behind dead standing trees and weakened limbs that could come crashing down unpredictably. And sections of the trails, bridges and embankments were destroyed or have slid out. The combination could result in fatalities or serious injury to hikers.
The Austin Creek property is closed entirely and suffered most in the intense firestorm.
But it could have been much worse. O’Neil said the ancient giant redwoods in the Armstrong grove escaped serious harm because there was little wind when the fire began backing downslope into the valley floor. That allowed fire crews to make a stand and accomplish the near impossible, protecting most of the old-growth trees there from harm.