After many weeks of logistical maneuvering, the Fox Drive Fire Prevention Project is kicking off with a bang as tree felling begins near Fox and Hoberg Drives. This project, funded by a CalFire Fire Prevention Grant, addresses the ongoing tree die-off in the Cobb area. For those of us who live in Lake County, this unusual color change on our mountainsides from green to red has been catching our attention and stoking our unease since the summer of 2021. But what exactly is causing the die-off? And what should we do about it?
In January of this year, CalFire released a report that confirmed that the die-off is caused in part by an outbreak of native beetles like the Western Pine Beetle. Western Pine Beetles, like other bark beetles, play out their lifecycle under tree bark. The Western Pine Beetle's tree of choice is ponderosa pine, and other coniferous trees have specialized beetles of their own. These trees have natural defenses against beetle attack, but when too many beetles attack an already-stressed tree at once, the tree can become overwhelmed and die.
As some of you may have already heard from UC Cooperative Extension Forester Mike Jones in the Lake County Tree Mortality Town Hall (linked at the end of this article), beetle outbreaks can be a natural part of life in a forest ecosystem. Outbreaks also don't necessarily increase an area's risk of wildfire -- when that area is out in the wilderness. However, when outbreaks take place in the WUI ("wildland-urban interface", as shown above where neighborhoods are interspersed with forest land), they can create hazardous conditions. Both because of wildfire risk and the risk of infrastructure damage when the tree falls, it is not safe or desirable to have a large, dead tree right next to your house.
Because beetle outbreaks are so large in scope, and very difficult to stop once they start, one of the best ways to reduce the risk that they pose to people and homes is to focus on treating areas directly adjacent to homes. Our Fox Drive Fuel Reduction Project has honed in on an area where standing dead trees are exceptionally close to homes, as shown in the picture above.
While bark beetle outbreaks are hard to stop, there may be additional steps that forest landowners can take to prevent future outbreaks. The Forest Service suggested in a 2010 management guide that forest health treatments, like selectively thinning overly dense tree stands to create more diversity in age classes and tree species, might reduce stress on vulnerable trees. If you are a forest landowner and are interested in implementing forest health treatments on your land, check out the North Bay Forest Improvement Program, a regional forest health cost-share program.
Ultimately, bark beetle outbreaks are sad to witness, but death and change are also important and natural parts of forest ecosystems. On Cobb, CLERC is helping to target specific high-risk areas. Outside of areas adjacent to important infrastructure, neighborhoods, and evacuation routes, it might be best to let the beetles do their thing -- the woodpeckers are certainly happy with it.
To learn more about tree mortality in Lake County, check out the Tree Mortality Town Hall video below.
The latest news, views, and perspectives from the Clear Lake Environmental Research Center (CLERC)