Bringing Lassen's Aspens Back from the Brink
● By Laura Christman
Vanishing ActOctober 2014
By Laura Christman
Photos: Tom Rickman/Lassen National Forest
Aspen trees in the west are doing a slow fade. During the past century, stands have lost trees or disappeared entirely.
Lassen National Forest is helping the pale-bark trees with rustling leaves regain ground in Northern California. “I find they are doing an exceptional job,” says Dale Bartos, retired aspen ecologist with the U.S. Forest Service Rocky Mountain Research Station in Logan, Utah. “I wish a lot of other forests were half as aggressive as they are.”
Ryan Burnett, Sierra Nevada group director of Point Blue Conservation Science, describes Lassen’s aspen restoration as a learning laboratory for California. Other land managers are using lessons from Lassen to help their aspen.
“It’s a great story of restoring an important habitat,” Burnett says.
Aspen are known for brilliant fall leaves that pop against the evergreen backdrop of the forest. But what’s at stake goes beyond their golden moment in autumn. Helping aspen isn’t so much about saving trees as it is protecting a valuable forest community.
The trees make up about 1 percent of the Northeastern California forest – a sliver of area with a disproportionate variety of plants and wildlife, notes Bobette Jones, ecologist for Lassen’s Eagle Lake Ranger District.
“There is an abundant and diverse understory of different grasses and sedges and flowering plants,” Jones says. The botanical mix draws birds, butterflies, deer and other creatures to aspen stands.
Ten million acres of aspen in the West have dwindled to less than 4 million acres, according to the Forest Service. In Rocky Mountain states, where more of the forest is aspen, helping the trees has been a focus since the 1980s, Jones says. Lassen National Forest began its aspen efforts 15 years ago. A survey revealed 6 percent of its stands were dead, and of those living, 80 percent were in a high state of decline. Trees suffered from intensive livestock grazing in the 1890s to 1930s and decades of wildfire suppression, Jones says. Without fire, conifers overtake aspen.
“Once they rise above aspen, they shade it out,” Jones says. The strategy to help? Logging. Lassen National Forest is bringing sunlight to aspen by removing conifers near them. Aspen react quickly, sending up shoots from roots to make new trees.
Point Blue Conversation Science monitors aspen stands where conifers have been logged, checking for 10 bird species that use aspen habitat for food, shelter or nesting. There’s been no decline in the aspen-associated birds, and seven of the 10 species improved significantly, Burnett says.
“The birds have really responded positively, more than we would have expected,” he says.
Conifers have been removed at 126 aspen stands— about 18 percent of the forest’s stands, Jones says. The effort, which includes environmental review prior to tree removal, continues.
“Our goal is to treat every aspen stand that needs it,” Jones says.
Aspen decline also is a concern at Lassen Volcanic National Park.
“Many of the stands I work with in the park have very, very few live trees left,” says Calvin Farris, park service fire ecologist.
An area near Manzanita Lake that once had thousands of aspen trees now has only dozens. Conifers are so thick that visitors don’t see the aspen, Farris says. Fire was discouraged in the park for nearly 100 years. While aspen can grow from seed, their primary reproduction is by sprouting – and fire triggers sprouting. Aspen trees burn readily, but their roots—if the fire isn’t too hot – survive. And with a root system already in place, the shoots grow with vigor, getting a jump start on conifers.
“With most conifers it takes several years to get 10 feet tall. Aspen can get 10 feet tall in a couple of years,” Farris says.
Lassen Park’s Northwest Gateway Forest Restoration to reduce fuel loads has been a boost to aspen near Manzanita Lake campground. Stands that seemed mostly dead started sprouting after firs were thinned earlier this year, Farris says.
Aspen also are popping up as a result of the 2012 Reading Fire.
“A lot of area the Reading Fire burned in the park hadn’t burned in a century,” Farris says. “The last major disturbance was the volcano itself – the mudflow and pyroclastic blast.”
The lightning-sparked fire was allowed to burn, but it escaped the park and became a 28,079-acre blaze threatening the community of Old Station.
“It wasn’t what the park wanted, to have the fire grow beyond the desired boundary, but ecologically there were a number of benefits of the fire,” Farris says.
As the forest rebounds, park visitors will see more aspen, he says. The trees are making a strong comeback in Hat Creek Drainage.
“I see it sprouting up in areas that I didn’t realize there were trees left,” Farris says.
Lassen National Forest, www.fs.usda.gov/lassen
Lassen Volcanic National Park, www.nps.gov/lavo