LAKE COUNTY, Calif. — Community members were offered a look at the causes behind the growing problem of tree mortality across Lake County during a virtual town hall Thursday night.

District 5 Supervisor Jessica Pyska hosted the tree mortality and fire prevention town hall, which was presented by the Lake County Risk Reduction Authority and the Tree Mortality Task Force, the latter created recently in response to the extensive dieoff of so many Lake County trees.

A key presenter on Thursday was Dr. Michael Jones, University of California Cooperative Extension forestry advisory for Lake County and an entomologist, who discussed the county’s conifer mortality.

Jones said this is a forest health issue, explaining that forests are very dynamic systems. “Disturbances are incredibly important in forests,” he said, adding that fire is crucial in the health of our forests.

He suggested thinking about it from two perspectives: ecological, the natural process that leads to sustainable ecological conditions; and utilitarian, the production of forest conditions which directly satisfy human needs.

It’s important to consider how to think about the situation. “It really dictates how we think about managing our forests” and what we do when we have outbreaks, Jones said.

Jones said disturbances can be abiotic, which includes weather, earthquakes, floods, snow, ice mudslides, climate, drought, fire and asteroids, the latter a reference to the Tunguska 1908 incident in Siberia in which an asteroid or meteor leveled a forest.

They also can be biotic, which includes the impacts of humans — historical land management practices, changes in land use, fire suppression and climate change — as well as animals, insects and diseases, Jones said.

Looking at all of the dead trees on the landscape, it’s known that they’re caused by bark beetles and pests. “But it’s really important to remember that insects are a natural disturbance,” Jones explained.

“The insects that we are observing and detecting in this current infestation are all native,” he said.

Those insects serve an important ecological process, helping maintain the dynamic heterogeneity of forest structure. Jones said they also serve as food for wildlife, help cull dead, dying and diseased trees, and are crucial to maintaining the health of systems.

From a utilitarian perspective, they become forest pests because they have economic impacts and are competing for resources, Jones said.

Those insects are always present but a lot of mortality isn’t seen all the time. Disturbances have to align to cause a high level of mortality, and a lot of different factors have to come into play, he said.

Jones is part of an effort to track the landscape-level mortality event from northern Mendocino County, through Lake, Sonoma and Napa counties. “It’s a pretty significant outbreak we're experiencing,” and one they’re comparing to the one that happened in the Sierra a few years ago.

Explaining how the system moves from stressed to dying trees, Jones noted Lake County’s significant years of wildfire and pointed out that wildfire stressed trees are attractive to these beetles and prove to be ideal bark beetle hosts.

He said they feed on dead trees and can complete multiple generations each year. The beetles then spread to other stressed trees and exponentially increase in population as they go.

When they run out of the fire-stressed trees, they move to healthier trees, with the beetles doing a “mass attack” on one tree at a time.

Jones said healthy and vigorous trees can defend against the beetles, pushing them out with sap or pitch. However, if it’s stressed from fire damage, in a dense forest or water stressed due to drought, the tree won’t produce pitch and then the beetles’ feeding eventually kills it.

Outbreaks don’t end from management, Jones said, explaining that the synergistic conditions need to fall apart to stop infestation.

The main insect impacting Lake County’s trees is the western pine beetle, with the ponderosa pine as its host. Jones said it’s typically found in stressed trees and isn’t usually the primary agency of mortality; typically it's the last part of a larger suite of forest health issues.

Other beetles impacting Lake County’s forests include the red turpentine beetle, which is hosted by pines; the ips bark beetle, which targets western pine species; and the flatheaded fir borer, which is hosted by fir and Douglas fir.

Handling bark beetles is a very complicated process that comes down to integrated management. “There’s no one right answer,” Jones said.

Options are thinning, pheromones, insecticides, removing and destroying infested material and planting nonsusceptible hosts. Jones said there are no effective pheromone treatments for the species they’re dealing with and while insecticides work well with bark beetle, they’re reserved for high value trees due to cost.

Once an infestation is established, it can’t be eradicated and the best strategy is to remove and destroy the affected trees, Jones said.

PG&E assessment finds hundreds of dead trees

Pacific Gas and Electric representatives Melinda Rivera and Dan Kida participated in the town hall, giving an update on the company’s midyear patrol of the Cobb Mountain area.

Rivera said they found an exponential number of trees that were dying from drought or beetle kill — more than they’ve found in prior years.

“We are making plans now to mobilize additional tree crews,” Rivera said.

While the company doesn’t usually do wood hauling, due to the unprecedented impact of the dying trees, she said they will offer parcel owners the opportunity to have wood removed this year.

Kida, who works for PG&E in vegetation management, said they recognized that just going through and conducting an annual patrol was not enough to pick up all dead and dying trees.

Now they do an additional patrol six months after the annual patrol and have added enhanced vegetation management, Kida said.

In the Cobb area, Kida said they have identified 750 dead and dying trees, significantly more than forecasted.

The company expects to start tree work in the next week or two. Meantime, Kida said they have enhanced vegetation patrols taking place around Loch Lomond and Middletown.

“We realize this is an unprecedented event,” and they are trying to work quickly to address it, Rivera said.

Rivera said community members wanting more information can call 877-295-4949 or email This email address is being protected from spambots. You need JavaScript enabled to view it..

More information on PG&E’s work is available here.

Fire chief warns of dry conditions

Paul Duncan, Cal Fire North Division operations chief, gave an update on the weather and fire conditions in Lake County.,

“We have not had significant rain since december. That’s really causing our environment to dry out here,” Duncan said.

He noted there have been several escaped control burns as well as higher fire spread.

“March 10 is really acting like June 10 for burning intensity,” Duncan said.

Duncan said Cal Fire is working to hire its seasonal firefighters by the first part of April.

Resources will be staffed up earlier, and large type one helicopters are going to be based in Sonoma and Napa counties.

Defensible space inspections will be taking place, Lake County County Fire will be working on escape corridors thanks to new grant-funded equipment and they've also been working to increase clearances around communications infrastructure, Duncan reported.

“Just be a good neighbor,” said Duncan, explaining that community safety is really about everybody in the community, not just one person, and it’s important to work on vegetation clearing.

He suggested that people report owners who are not clearing their property of hazardous vegetation should make a complaint to the Community Development Department.

Pyska noted on Thursday night, “A lot is happening. We take this work very seriously.”

Email Elizabeth Larson at This email address is being protected from spambots. You need JavaScript enabled to view it.. Follow her on Twitter, @ERLarson, or Lake County News, @LakeCoNews.