Bark Beetles Making Western Wildfires Worse

Despite spending only two weeks in the U.S. during their first tour in 1964, the Beatles had a huge impact on the country.

Prior to their return to the States six months later, the British band had 17 top-40 singles in America. Including six No. 1 hits.

Young people bought their records, sang to their records and danced to their records. Girls screamed and boys grew their hair to look like the band members.

And millions of Americans – young and older – watched their landmark performances on the Ed Sullivan Show.

Beetle Population Is Growing

Proving to be much less popular than John, Paul, George and Ringo are another group of beetles. These guys are native to the U.S. 

Bark beetles are killing trees in the West by the millions. And these tiny insects’ voracious appetites are making trees more susceptible to wildfires.

As temperatures rise annually in the West, the bark beetle population grows. Those higher temps allow the beetles to survive winter. And produce more offspring. Combined with drought, Western forests are more vulnerable than ever to fires.


The beetle problem might be manageable if they enjoyed bark from only one or two tree species. But they seem to enjoy pretty much any tree.

Matt Zaffino is a meteorologist in Portland, Oregon. He said, “The beetles go in, and if they’re not stopped, they literally destroy and kill a forest. They get under the bark and they kill the tree.”

Tiny Creatures Use a Chemical Trick

There are approximately 600 species of beetles in America. Only about 12 of them are known for boring into wood.

This activity disrupts the flow of nutrients into trees. And allows beetles to kill off large swaths of forests.

Each individual bark beetle is tiny – about the size of a grain of rice. But they’re instinctively clever. When they climb onto a tree, they emit a pheromone. This chemical trick draws in 10 to 100 other beetles for a combined attack.

In addition to getting a little help from their friends, the beetles also emit another pheromone. This one tells other beetles not to join them when they have enough attackers. Those other beetles can then start in on a different tree.

Fungi Adds to the Problem 

Some of these beetles carry fungi with them. They use it to feed their offspring. The beetles and fungi are deadly to trees. 

There is talk from tree experts that bark beetles are helping make the current Bootleg Fire in Southern Oregon so devastating. As of this writing, it’s the largest active fire in the country. It has already destroyed more than 400,000 acres.


Beetle infestations are also being blamed for the spread of the Creek Fire in 2020. It was the largest fire in California history.


Rebecca Wayman is a forest ecologist at the University of California-Davis. Here’s what she told Vox about the situation.

“In the past, (bark beetle) outbreaks were more limited in extent or intensity. Now that we’ve seen such severe outbreaks with huge proportions of trees being killed, the effect on fire is certainly high on people’s minds.” 

Beetles Kill More Trees Than Wildfires 

We’re all aware of how much destruction wildfires have caused through the years. And we know it keeps getting worse every year.

But the Forest Service reports that bark beetles have killed more trees over the past 30 years than all wildfires in the U.S. combined.  

Mainly because the bark beetle population has grown out of control. In one recent year, they infested nearly 9 million acres of Western forests.

Dry conditions cause trees to close their microscopic structures (stomata) that absorb carbon dioxide. That lack of CO2 makes them more susceptible to beetle attacks.

‘Greater Potential for Mass Fire’

Within a year of a beetle attack, some pine trees can lose as much as 80 to 90 percent of their water content. 

Dry trees are much more flammable than healthy ones. The beetles can even reduce the amount of forest canopy cover. And that allows winds to blow through the forests quicker. This also contributes to spreading wildfires.

The more dead and dying trees there are, the more easily wildfires can spread to healthy trees. 

Chris Fettig is a research entomologist at the U.S. Forest Service. He said, “The scale of present tree mortality is so large that greater potential for mass fire exists in the coming decades.”

The Battle Is Raging

Ways to limit the damage done by bark beetles are limited. Controlling their population has proved impossible so far. One method being tried is controlled burns. And removing certain species of trees from forests.

Controlled burns can lower the risk of wildfires by reducing the density of trees. This allows surviving trees to have access to more water. Hydrated trees can defend themselves better against bark beetles and wildfires.

It’s going to be a long and winding road, but some people are trying to come together to limit the effectiveness of these beetles.

Let’s hope it happens before even more of our forests are decimated by wildfires.


  • Ken Herrmann - August 16, 2021

    This article on the beetles is well thought out and fairly complete except for the fact that it DOES NOT address the root of the problem in the fire prone areas of the west. MAN.
    No, I am not talking about the supposed man caused global warming or climate change (in the history of our earth there have been times when CO2 levels were higher with lower temps and lower with higher temps – glacial ice studies).
    Primarily over the last 100 years or so Man has taken it upon him/herself to “protect the environment” by “saving our forests” and has done just the opposite.
    I have spent some time living in the Sierra Mountains in California. U.S., and doing Forest surveys in Baja California, Mexico
    Human caused FIRE REDUCTION is the main cause of our catastrophic wildfires. The forests of Baja are healthy, rich in wildlife, and carbon sequestration, and there are beetles there. The forests of the U.S. West are overgrown thickets of trees that through competition have become stressed and weakened. This then promotes disease and die off and the “smell” of this calls to beetles which then find a smorgasbord of food to infest and reproduce thereby causing bigger impacts on those areas that might have been doing better, as in Baja.
    The primary difference between these two areas, of the same forest type, are that fires are not stopped when they start. Fire history in the Sierras of Baja show many small fires that burn themselves out whereas in the U.S. West humans have worked to stop all fires – so now we have major conflagrations in unnaturally dense forests and covering much larger areas.
    The main difference between an “environmentalist” and a forester is that the “Save our Forests” groups chain themselves with their backs to the trees to “protect” them, while Foresters face the trees to measure their diameters to understand their lumber volume and promote the same forest health in a sustainable manner.
    The Society of American Foresters and the U.S. Forest Service have had this science for decades (why do you think controlled burns have been happening in Yosemite?) but the “environmentalists” continue to fight science and nature and now blame “Global Warming” for Mother Natures efforts to reset our forests through the natural clearing function of beetles and fire.
    Mark Twain once said “If you don’t read the newspaper you are uninformed, if you do read the newspaper you are mis-informed”. Paul Harvey also used to say “and now you know the rest of the story”


  • Darlene Davis - August 16, 2021

    When a beetle-infested tree burns, I would expect that the beetles in it are killed. Maybe the wild fires control the beetles so that new trees can survive.

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