The ongoing spruce beetle outbreak in Alaska has now affected 2.25 million acres statewide, but last year, the new forest damage attributed to the beetles hit its lowest point since the outbreak began nearly a decade ago.
That’s according to a March 3 update from a joint state and federal effort to track the outbreak.
Jason Moan is a Forest Health Program Manager with the Alaska Division of Forestry and Fire Protection. He said, using aerial surveys and other monitoring techniques, the agencies spotted about 35,000 acres of spruce beetle activity in 2024.
“That simply refers to places where beetles were active in attacking trees when we flew the survey or when we were on the ground looking at the trees,” he said.
The outbreak peaked in 2018, when monitors saw almost 600,000 acres of spruce beetle activity in one year.
It’s been on a zig-zagging decline since then, so reaching a low point this year doesn’t necessarily mean next year will have even less activity. In 2022, for instance, about 49,000 acres of activity were spotted, while in 2023, that number surpassed 90,000.
But Moan says the dip is still a good sign.
“It is certainly a promising development. And as we have seen it declining, while there is those fluctuations, we are still generally heading in the right direction,” he said.
Spruce beetles are small — a quarter-inch long and eighth-inch wide in adulthood — and reddish-brown in color. They live and feed underneath the bark of trees, and they can target all types of spruce in Alaska.
The beetles are native to the state, and previous outbreaks have also killed millions of acres of trees.
The current iteration gained footing in Southcentral Alaska in 2016, but over the last couple years, spruce beetle activity in that region has tapered off. It’s now clustering mainly on the outbreak’s northeastern frontier.
Moan said that’s largely due to the three things that dictate where the beetles can live: a lack of predators, the availability of host trees, and warm enough temperatures to survive overwintering.
“If those things are lining up for them, like they have been for the last few years, in the lower Denali Borough and the … northeastern Mat-Su Borough, then we see that activity continue,” he said.
Faded yellow needles and dust at the base of a tree are among the first visible signs of a spruce beetle infestation, and Moan said spring is a good time to start checking in on tree health. Additional information and resources about the beetles and outbreak management can be found here.