The warmest winter in Colorado history could lead to record-breaking proliferation of a tiny insect, about the size of a grain of rice, that has killed millions of acres of trees across the Centennial State and contributed to the rapid spread of some of its largest wildfires, according to state officials.

Mountain pine and spruce beetles, which are native to Colorado, have recently appeared in larger numbers along the Front Range, the State Forest Service said. The insects feed on several species of pine trees, including lodgepole and ponderosa pines, which occupy much of the state’s forested land.

The beetles lay their eggs in the tree bark, and when the eggs hatch, the larvae produce a fungus that inhibits the tree’s ability to draw water and nutrients from the soil, essentially starving the tree to death.

When the trees die, they dry out and create ideal fuel for wildfires, according to State Forester Matthew McCombs.

“Each year, we conduct aerial flights to try to detect insect and disease activity in our forests,” said McCombs, who heads the Colorado State Forest Service.

“When the data came back in September, it was very evident that we were seeing an outbreak in pockets all across the Front Range.”

Historically, the winter months have produced enough cold weather to keep the beetle population under control. But record-breaking temperatures across the state, plus severely low precipitation, have created conditions that allow the insects to thrive, McCombs said.

“When you get a cold snap, with two to three weeks of negative-degree temperatures, you can see some larva mortality, and that can give a tree a fighting chance,” he said. “But we haven’t seen that. Under the current conditions, we can expect to see substantive increase in (beetle) population and impact.”

Water helps trees fight beetle infestations by enabling them to produce sap, which can trap beetles and force them out of entry holes. But the low snowfall robbed many Colorado trees of that natural defense mechanism.

“When there’s no water, trees become defenseless,” McCombs said.

According to the National Weather Service’s climate prediction center, this spring is expected to be warmer and drier than normal, which could lead to the kind of conditions that fed the state’s worst fires.

These conditions would be particularly concerning in the Front Range, where communities, homes and infrastructure are in close proximity to forests.

“A worst-case scenario would be a warm, dry winter followed by a warm, dry spring,” McCombs said. “We could still get bailed out by a massive storm in April, but the conditions are concerning so far.”

Forestry experts expressed their concerns to local and state leaders, including Gov. Jared Polis. And in December, the governor announced the creation of the Ponderosa Mountain Pine Beetle Task Force, a cross-jurisdictional group focused on addressing the risks posed by beetle-killed trees, educating homeowners on what they can do to protect their properties, and other short- and long-range initiatives.

“As the latest outbreak of pine beetles begins to take shape along the densely populated Front Range, we are taking an aggressive approach to boost tools and partnerships to help protect our communities, forests, and key water sources, and equipping homeowners with the resources they need to better protect their homes. I am grateful to our local partners, foresters, and leaders across sectors for helping us take action on this issue,” Polis said in a statement.

“We are incredibly thankful to Gov. Polis and other state leaders for recognizing the scope of the problem and acting swiftly and decisively,” McCombs said.

There are several things that homeowners can — and should — do to help state, county and local agencies mitigate potential beetle damage, officials said.

“Our field offices are there to support folks, but our capacity is limited,” McCombs said. “We need property owners to do what they can to help.”

Residents with pine trees on their property should keep them watered to help them produce sap. People who chop down trees for firewood should burn the wood locally.

“We don’t want people moving the beetles around,” McCombs said.

Trees that may be susceptible can be treated with insecticides or a synthetic pheromone that tells beetles a tree is already occupied.

“We also want to educate people on how to identify infected trees, cut them down and remove them prior to beetle flight,” McCombs said. “For every one tree that’s affected, beetles can infect anywhere from three to 10 additional trees.”

Land owners are encouraged to educate themselves on what pine mountain beetles look like and to contact the local Forest Service office if they see any on their property.

“We’re not arguing that the world is going to end because of beetles,” McCombs said. “But we have to think long term to prevent the conditions that killed our lodgepole systems years ago. As those trees died and came down, the systems collapsed in on itself, and mixed with other dead heavy fuels. That fomented the growth that we saw in the Cameron Peak and East Troublesome wildfires.”