By Kathleen Wong, UC Natural Reserve System
To step into Valentine Camp is to enter the forest from a childhood fairy tale. Dense stands of Jeffrey pine, red fir, and lodgepole pine line its access road and cloak slopes that tilt east toward the Sierra Nevada. The trees grow so thick that it is easy to imagine Hansel and Gretel getting lost within this UC Natural Reserve.
Primeval though these woods might appear, their condition is highly unnatural. Since the late 1800s, when miners first established the town of Mammoth Lakes, people have doused every fire here as fast as they were able. Fire scars within tree cores, however, indicate that this forest used to burn once every 15 to 40 years prior to European settlement. More than a century and a half of fire suppression has left Valentine Camp’s forest in questionable shape.
“The lack of fire in that system for many, many years has led to a high density of trees—so high that it’s not healthy for the forest. It’s not what you want when you are surrounded by people and houses and this wildland-urban interface,” says Carol Blanchette, director of Valentine Camp.
Wildfires across California have exploded into one unstoppable inferno after another in recent years. Blazes have torched entire communities as well as multiple NRS reserves. Hotter summer temperatures due to climate warming, combined with record droughts, have killed an estimated 150 million trees in the Sierra Nevada. Weakened survivors grow vulnerable to bark beetle attacks. Meanwhile, the proliferation of dead, standing trees has dramatically increased the likelihood of fast-spreading canopy fires.
Bordered on one side by homes, and on the other by Mammoth Mountain Ski Area, Valentine Camp’s small forest poses a major fire risk to the town of Mammoth Lakes.
Opportunity thanks to Cal Fire
The twin specters of forest decline and catastrophic wildfire spurred Blanchette to initiate a forest thinning project at Valentine Camp. A $500,000 California Department of Forestry and Fire Prevention (CalFire) grant will pay to treat about a third of the reserve’s 155 acres. The area being treated represents the majority of the forested portion of the reserve.
“We’re doing this for two main reasons,” Blanchette says. “To protect the reserve and surrounding community from burning down if a fire came through. And second, we want to make forest itself more resilient.”
The massive wildfires that have convulsed California over the past decade have allowed Cal Fire to justify providing larger grants that support thinning across sizable tracts of forest. The CalFire Community Fire Prevention Program “was a perfect fit for what we wanted to do,” Blanchette says.
The logic behind forest thinning is easy to grasp, says Hugh Safford, regional ecologist with the USDA Forest Service and a researcher at UC Davis. “Forest trees are like straws in a drink. If you have too many straws, the water’s gone fast. If you remove half, the water lasts much longer,” he says. “The plants are healthier, their growth rates are faster, and they don’t burn as easily.”
Blanchette’s predecessor, Dan Dawson, had parts of Valentine Camp’s forest thinned before. But the scope of those projects was limited by the funding available at the time. And if not maintained, treatments last a couple of decades at most.
A learning opportunity
Blanchette recognized the forest thinning project as a chance to learn how fuels reduction efforts can affect the health of a montane forest. “Because the Valentine Camp is an NRS reserve, we have the opportunity to do a meaningful research project at the same time that we are managing the forest,” Blanchette says.
Blanchette enlisted Safford’s help to lay the groundwork for a study. Last summer, a full year before any logging began, he directed his crew of seven international forestry interns to assess the Valentine Camp forest.
How to measure a forest
The interns began by setting up 50 circular, 400-square-meter plots across the reserve. Within each plot, they painstakingly identified each plant species and assessed their abundances. They also counted every plot’s trees, evaluated their sizes and health, and estimated forest fuels.
Safford intends to repeat these measurements for years after the forest thinning treatment. The data will help future researchers measure how forest thinning affects tree densities, carbon content of the forest, biodiversity, and the amount of combustible material on the landscape.
“In the long term the thinning should lead to a higher diversity of plant species. We can help demonstrate that this is true,” Safford says.
Fodder for a Ph.D.
One researcher has already made plans to study Valentine Camp’s forest treatment in detail. Ashley Grupenhoff is a graduate student in ecology at UC Davis. Safford is her faculty advisor.
“Valentine is an ecological reserve that’s been well studied. I was really excited when I heard about this project to get in there and follow what is going on.” Grupenhoff says.
Grupenhoff intends to examine how thinning has affected forest resilience. Her methods will include assessing the water status of many individual trees.
“The reserve is a really diverse hotspot for birds and plants. But we see these pockets of high beetle mortality, a lot of dead trees, really squished in there. The treatment makes sure biodiversity at Valentine Camp persists into the future, and might even enhance it.” Grupenhoff says.
Grupenhoff also wants to measure how much forest thinning will reduce the threat of fires. Using computer models, she will estimate how the treated forest will change over time, and examine how the changes in stand structure affect fire behavior.
“Is this treatment going to prevent these catastrophic fires into the future? What does it look like if fire were to come through again?” she asks.
Grupenhoff is already deeply familiar with forest dynamics. When not working on her graduate studies, she has run a Cal Fire crew that monitors prescribed fires for the past two years, and served as a fire ecologist for two years before that.
“Continuing to burn every few years will keep a lower fuel load on the landscape, and get rid of some of those white fir seedlings and saplings. It will make for a stronger and more resilient landscape,” Grupenhoff says.
Which can stay and which must go?
Work on the Valentine Camp thinning project commenced this summer. Figuring out how many trees to cut, and which needed to come down, was the first concrete step. For this assessment, Blanchette hired a registered professional forester.
The forester’s report indicates the reserve now harbors an average of 500 trees an acre, but in some areas is as dense as 900 trees an acre. The goal is to slash the density in much of the reserve to around 150 trees an acre.
The trees chosen for removal are the smallest, most spindly individuals. This is the opposite of commercial timbering practices, which tend to remove the largest, most profitable, and generally least flammable trees in a forest.
Younger trees tend to be more vulnerable to burning. Their many dead, light-starved branches also serve as ladders to spread fires into the canopy, where flames can ignite an entire forest.
A noisy summer and fall
Throughout summer 2020, reserve neighbors have heard the high pitched roar of chainsaws throughout the reserve. Crews have thinned about ten of the fifty acres slated for treatment to date.
For a community accustomed to viewing Valentine Camp as a nature preserve, “it looks a little shocking to see truck after truck of logs coming out,” says Blanchette.
Right now, the green and peaceful heart of Mammoth Lakes is anything but. “Logging is a disturbance. For the first few years after fuels treatment, the site looks like hell,” Safford says.
To counteract misunderstandings about the project, Blanchette and her colleagues have been doing their best to inform the town about the project. They’ve developed a flyer describing the work, and have invited both Safford and Grupenhoff to give a talk about the thinning project this Nov. 19 as part of UC Santa Barbara’s Natural Reserve System virtual seminar series.
Those outreach efforts have already paid dividends. “We have a lot of neighbors and they’ve been so supportive. Ninety percent of people have been super supportive; we get tons of emails saying they’re so thankful and happy we’re doing this,” Blanchette says.
Tree removal at Valentine Camp will continue until the end of the year. Although the grant expires next spring, Blanchette says, “the effective deadline is when it starts snowing.”