USA – Many trees in East Bay regional parks are dead or dying — likely due to lack of rainfall — and officials fear the trees could catch fire and that the flames could sweep through the parks and reach nearby homes.
The trees cover about 1,000 acres of the 124,909-acre district, and multiple species are affected, including acacia, eucalyptus, Monterey pines, manzanitas and others.
Most of the trees, on about 624 acres, are in Castro Valley’s Anthony Chabot Regional Park, where eucalyptus grow in some places so close together that game trails do not exist. The second biggest concentration, with about 177 acres, is in Reinhardt Redwood Regional Park in Oakland.
“It’s quickly coming to a point where it’s a matter of public safety, with fire season looming,” district Fire Chief Aileen Theile told the park district’s citizen advisory committee recently, adding: “No action is not an option at this point.”
Many trees are in “interface” areas, Theile said, or where parkland abuts residential neighborhoods, making the fire threat especially dangerous.
Crews began noticing the number of ailing trees last October while doing scheduled vegetation cleanup.
Since then, the district has carried out a helicopter survey to pinpoint where trees may be dying and workers have continued clearing out leaves, cutting branches and removing some trees that are dead.
A controlled burn was planned for this month at Tilden Regional Park in the Berkeley hills — where an estimated 62 acres of trees have been impacted by the drought — and Albany is evaluating the extent of eucalyptus decline on Albany Hill and how best to manage it for safety and to sustain habitat for monarch butterflies.
Monarchs gather in eucalyptus because the shape of the leaf on the trees makes it ideal for them to cling to, plus the trees shelter them from the wind, according to naturalists.
“Wildfires are scary,” Lyra Ryan, 23, of Berkeley said recently while biking through Tilden Regional Park. “I would prefer if nature was left undisturbed and it was just let be. But I also don’t want people to have their houses burned down and lose all their stuff.”
Natalie van Doorn, a research urban forest ecologist, and Susan Frankel, plant pathologist, both with the U.S. Department of Agriculture Forest Service, Pacific Southwest Research Station in Albany, said tree decline is happening locally from south of San Jose to north of the Carquinez Straits.
Frankel and van Doorn are working to scientifically determine the causes, but they suspect it’s the lack of rainfall, noting that Drought Monitor — a government map that monitors the location and intensity of drought across the country — shows the Bay Area is now under an extreme drought. Rainfall levels for this past rainy season in most Bay Area cities was at 35% to 40% of normal.
Lack of rainfall can make trees more susceptible to pathogens and parasites.
“There are scattered fading or dead trees along major highways throughout the Bay Area and in many yards and open spaces,” Frankel and van Doorn said in a joint email. “The pattern of decline and mortality is patchy. There are many areas that still look fairly healthy adjacent to areas with trees that are off-color, and have lost most of their leaves or turned red (died).”
What complicates things is that some trees that appear dead can recover because their roots remain alive, what’s known as a “die-back.”
“It is surprisingly difficult to tell when a tree has actually died,” Frankel and van Doorn said. “A tree can appear with totally brown leaves, or all the leaves may drop, leaving a bare crown — but then eventually some of those trees may push out new growth and recover.”
Eucalyptus and acacias are known to vigorously resprout when people cut them, they said.
“In terms of fire danger, a tree with dead leaves on its branches is more susceptible to burning and will provide fuel to the fire, more so than a tree whose dead leaves have fallen off already,” they said. “However, standing dead trees may pose additional safety concerns, if the trees are located near trails or homes and are at risk of falling.”
Along with the park district and forest service, UC Berkeley’s Forest Pathology and Mycology Lab and the California Department of Forestry and Fire Protection are among the agencies investigating what’s causing the dead or weakened trees and what should be done about it.
Local organizations, such as the Friends of Sausal Creek and Friends of Joaquin Miller Park, are helping identify locations of the trees.
The park district spent $2.3 million on vegetation work last year, Erich Pfuehler, the district’s chief of government and legislative affairs, told the citizens advisory committee. The committee’s 21 appointed members offer advice and recommendations to the district board.
The district has spent $20.5 million in controlling vegetation over the past 10 years, Pfuehler said.
Funding sources include grants from the Federal Emergency Management Agency and Measure FF, a parcel tax voters in Oakland, Berkeley, Richmond, Alameda, San Pablo, El Cerrito, Albany, Emeryville, Piedmont, El Sobrante and Kensington passed in November 2018.
The Oakland hills firestorm of October 1991, which killed 25 people and destroyed about 2,800 houses and more than 400 apartments and condominiums, has spurred the district to focus on the trees, Pfuehler said.
“With the ’91 Oakland hills firestorm, the park district really determined we needed a program of reducing vegetation in the East Bay hills so that we could contain a fire more quickly,” he said.