Scientists doing field-based research saw a decline in the death rate of ponderosa pines from western bark beetle infestation last year, but Tuolumne County isn’t slowing down its effort to help landowners affected by the drought-induced epidemic.

The U.S. Forest Service estimated about 27 million trees died last year throughout California, a drop from a high of 62 million trees that died in 2016. Much of the reduction has been credited to the heavy precipitation the state received during the winter of 2016-17.

An estimated 129 million trees have died throughout the state since 2010, with roughly 7 million believed to be dead in Tuolumne County.

Since July 2016, the county has completed 33 projects that have collectively removed more than 5,000 dead trees. That doesn’t include tens of thousands more in the county that were removed by Pacific Gas and Electric Co., Caltrans and the U.S. Forest Service.

“There’s still a huge need,” said Ryan Campbell, county administrative analyst working on tree mortality projects. “The relatively wet weather we’ve had for the past two years has had a positive impact, but the damage was already done before we got these storms.”

Much of the work the county has completed so far was focused on removing dead trees along the sides of county-maintained roads, because state funding from the California Disaster Assistance Act could only be used to protect public infrastructure as opposed to private property.

Efforts are ramping up this year to remove dead trees that are threatening homes and private roads using a $2.4 million grant the county received from Cal Fire in early 2017 that came from a mix of state funds and fees collected from landowners in the State Responsibility Area.

“Those were two areas we saw that fell through the cracks and left a lot of people in danger, so we found funding to help people in those situations,” Campbell said of private property and roads not maintained by the county.

The county has completed about three projects on private property and seven on non-county maintained roads so far. About 30 projects through the county are planned for the next phase that must be completed by March 2019 based on the grant’s requirements.
Campbell said areas were selected based on the number of dead trees and population density.

“We have a GIS mapping system which shows us where pockets of high density are, and we can overlay that on satellite maps to give us a rough estimate on how many dead trees are in that area,” he said.

The county then sends out a registered professional forester to assess the types and numbers of dead trees in specific areas.

Private property owners must fill out and return a “right-of-entry” permit to the county in order for the foresters to assess trees on their land. The required paperwork has led to some delays on projects getting started because the county tries to get a return rate of 75 to 90 percent before moving forward.

With the help of the $2.4 million grant, the county has developed an online form for the new projects this year that will allow landowners to fill it out electronically and submit it to the county in a matter of minutes.

“People will get a notice in the mail that tells them the steps to go through to file (the permit),” Campbell said. “If they didn’t get one, then it’s probably because they are not in one of our project areas.”

Campbell said people can also call the county’s tree mortality hotline at (209) 533-6394 to see if they are within a project area. The county has fielded more than 650 phone calls about the issue since late last year.

The county has been considered a leader in the state when it comes to responding to tree mortality since Gov. Jerry Brown declared a state of emergency for the issue in October 2015.

Jodi Axelson, a Cooperative Extension specialist in forest health at University of California, Berkeley, said the slowing of mortality seen over the past year should give counties like Tuolumne an opportunity to catch up on removing dead trees from private property.

Axelson is part of a team of scientists collecting data on tree mortality that also includes John Battles, a forest ecology professor at UC Berkeley, and Susie Kocher, a natural resources advisor for UC Cooperative Extension, Central Sierra.

The team collected data on tree mortality from eight plots throughout the state that were each about 2-square-kilometers in size and contained about 30 to 35 tree stands each.

“What we’ve seen with that data is by 2030, all of our plots are going to have large amounts of fuels on the ground,” Axelson said. “We’re really committed to following these stands to the best of our ability and get that data out to land managers and county folks.”

Axelson said that areas between about 3,000 feet and 4,000 feet in elevation tend to have very heavy mortality of ponderosa pines. This is partly due to trees at higher elevations being able to retain more water due to cooler temperatures.

While the drought is largely to blame for making the trees more susceptible to beetle infestation, Axelson said another factor is overcrowding in the forest.

“Think of the forest as a glass of water,” she said. “There’s a fixed amount of water and how fast that water will go away if you have 10 straws in the glass versus 50 straws. You have these really dense forests where the trees are all competing for that same water.”

Axelson said some trees that didn’t die during the current epidemic may have a better chance to fend off beetles during a future drought cycle due to there being fewer trees competing for the water.

However, the trees that have already died continue to pose a fire hazard and risk to public safety.

“The problem with all of these dead trees being a threat to people and infrastructure isn’t going away, so this is probably a good time to get in there and remove them,” she said.

Contact Alex MacLean at or (209) 588-4530.