How to navigate the ongoing bark beetle outbreak

May 27, 2021

A spruce tree killed by bark beetles lies in a stand of live birch and spruce trees in June 2020.
Credit Elizabeth Earl / KDLL

If you’ve been around town a few years, you know how drastically different Kenai and Soldotna look now than they did two summers back. That’s in part because of the loss of a vast number of spruce trees, killed by the spruce bark beetle.

The Kenai Peninsula is in the middle of a spruce bark beetle outbreak, the worst in recent years. The little brown beetles burrow in and eat the tree’s phloem, which is the connective tissue that allows trees to move sugar around after photosynthesis. Bark beetles are a native part of the ecosystem here, but in the last three or four years, their activity has spiked.

Doug Koch of Pro Tree Service in Kenai has been felling trees on the peninsula since 1993. In the last four years, he said he’s seen a big uptick in the number of dead spruce trees.

It started around Central Peninsula Hospital in Soldotna and spread outward to Kenai, Soldotna and across the Central Peninsula. He said it’s mostly the taller, older trees that go, but he’s seen trees of all sizes fall victim to the beetles.

He said he saw the same thing in the 1990s in the Homer, Anchor Point and Ninilchik area, when the beetles ripped through the spruce trees there. Unfortunately, with the beetles this active, there really isn’t much to do to save them. If a property owner does choose to spray the tree, it has to be the whole tree — Koch said he’s seen parts of trees sprayed, but the beetles got the unsprayed part anyway.

John Winters, the stewardship forester with the Alaska Division of Forestry for the Kenai Peninsula and Kodiak, said this is the worst he’s seen it since the 1990s.

"[In the central peninsula communities] it's as bad as I've ever seen it," he said.

The beetles seem to primarily target older, taller trees, and the overall age of the trees on the central peninsula seems to be a big factor. Winters said the drought two years ago also played a role in helping the beetles spread. He said there are a couple of clear signs of a beetle attack, and typically by the time they’re visible, it’s too late for that tree.

"Two indicators of a recently infested spruce tree would be one, what’s referred two as boring dust," he said. "It’s a fine, brownish dust that can be found at the base of the spruce tree. The other one would be what’s referred to as a pitch tube, and what it looks like is small gobs of brownish or yellowish colored substance on the side of the tree. It looks like either glue or some type of caulking. If you see either of those on the side of a spruce tree, that’s an indicator that that tree was recently attacked by a spruce beetle."

However, losing the spruce trees isn’t all necessarily bad for the peninsula. While this is a big outbreak, it may lead to more diversity in the forests on the central peninsula. While the southern peninsula is mostly spruce and other conifers, the central pensinsula also has hardwoods like birch, cottonwood, aspen and alder. Winters said the loss of the spruce trees may leave room for those to grow up and diversify the forests, making them less vulnerable to mass beetle wipeouts in the future.

"A couple of forest management goals that landowners should consider is species diversity and age diversity within species," he said. "Here in the central peninsula, we have an opportunity in these mixed forests where there are aspen, birch, cottonwoods in addition to the spruce, to have those trees to come in and replace where we lost all of our spruce trees due to this infestation. If we have young spruce trees coming in, likewise, it will be many years before those trees will be old enough to become infested by spruce beetles, so there’s a chance to enjoy younger spruce trees."

He said property owners can help by transplanting and seeding new trees into lots they want to reforest, which can be important to help prevent other plants like grass from taking over and making it harder for trees to become reestablished. Protecting young trees from hungry moose and snowshoe hares for a few years after planting them can help, too.

For those with a lot of dead spruce trees, one big consideration is when to get them taken out. Winters said the main factor in when a spruce tree will fall is core rot — which can happen to green trees, too.

Koch, who’s busy felling trees all over the central peninsula, said trees can typically wait a year. He said he sees people panicking and hiring people to remove trees as soon as their needles drop, but that can be a mistake, as they may be rushing and hire someone without experience. He recommends people get at least two bids, get references, and if they don’t like the options, wait for someone better. He said he’s seen some tree drops go poorly, like hitting a neighbor’s house or a powerline.

For more information about spruce bark beetles, go to AlaskaSpruceBeetle.org.