Life in Alaska
Outdoors & Recreation

Spruce Bark Beetle

Written by
Wendy Wesser

“Oh no, we have a problem,” I said to my husband last summer. “Our two tallest spruce trees are dying! The spruce bark beetles have attacked and won.”

It seemed like one week these two trees were healthy and the next week their needles were turning red. If I’d been paying closer attention I may have noticed the tell-tale tiny holes and the red sawdust-filled pitch oozing out of their trunks. These two giants were a focal point in our yard, but they no longer looked at all attractive. Was it too late to save them? Yes, and that was okay. Several younger spruce are growing up nearby, ready to take their place. Joel with Valley Tree Service said that the trees near the dying ones he cut down would sprout up fast with the extra daylight they will receive.

Beetle-Infested Spruce

So we had our two trees cut down and got more proactive in saving the remaining spruce on our property. We have over two acres of land with several dozen spruce trees so I decided I needed to make a more thorough survey of the remaining ones. I was surprised to find another large dead spruce with brown needles, but so far the rest are looking good, probably because they are much younger than the three we lost.

“Oh no, we have a problem,”

Back in the 1990s we lived on the hillside in Anchorage, when the Kenai Peninsula was devastated by spruce bark beetles and lost millions of trees. I was taking a master gardener course through the Cooperative Extension Service at the time and one of the hot topics was how to protect the spruce in Anchorage. A gentleman in the class had property near Kenai and he stated that he hadn’t lost one tree. We were all very surprised at his claim and a little dubious. Wow! How did he do that when so many spruce on the Peninsula had been killed in just a few years? He said that every spring he scatters 8-32-16 granular fertilizer around the base of each spruce.

I followed this man’s advice on my half-acre Anchorage property and then a few years later on our land in Wasilla. Until last summer we didn’t lose one tree. I did not fertilize my trees in the last couple years when I should have. After doing some research and confirming with Jesse Moan of the UAF Cooperative Extension Service, we are going to try that method again. She said we should keep our nitrogen below 15 to prevent causing other problems. First we will make sure our trees are not suffering from drought and then we’ll apply the fertilizer. Because the spruce bark beetles are looking for new host trees from May through July, this is a good time to water and fertilize healthy spruce. Use the amount recommended on the fertilizer package you buy. There are no guarantees that this will work, but it’s worth a try for the spruce near our home.

Another option for some is spraying high-value trees, but that is not a consideration for us. There are a lot of reasons we won’t spray our trees: we live near a lake, we have grandkids, and we don’t want to risk harming the birds, bees, dogs, cats, and wild animals that live and wander on our property.

A couple other recommended things that we will do next fall is to thin some of our remaining spruce and trim off the lower limbs. It is important to wait until the spruce bark beetles are done flying before doing these activities, unless you want to attract more of them to your property. I’m going to wait until September to be sure.

Many people don’t know that spruce bark beetles are native to Alaska and not an introduced pest. They have been here as long as spruce trees, are a natural part of a healthy ecosystem, and they help decompose weaker trees to make room for healthier habitat. Once the female beetles successfully enter a tree, using pheromones, they invite their male friends and other females to join them. Just one of these ¼” beetles can lay well over 100 eggs after boring its way into a tree. They, along with their offspring, will live, mate, dine, and spend the winter under the bark until they head off to another tree. They are just doing the job that they’ve been responsible for long before humans came on the scene.

Spruce Beetle Larva

Every few decades the spruce bark beetles get out of hand like they are now in the Matanuska and Susitna River Drainages. Why now? The probable cause is the severe wind storm in the fall of 2012 that took down many trees and a couple of hot dry summers since then. Those events may have stressed the spruce tree population and signaled the beetles that their services were needed. According to a chart I found on the United States Department of Agriculture Forest Service website, in 2015 the number of acres attacked statewide was 33,000. By 2018, that number rose to 593,000 acres. This year the number is projected to go over a million acres.

How much should we be doing or not doing to curtail the spruce bark beetle activity is a subject that is debated among professionals. So don’t get too upset with your neighbor if they don’t take care of their trees the way you think they should. Some say we should do all we can to stop the beetle damage and others say let Mother Nature do her job and let’s spend our resources on other pressing needs like firebreaks to protect communities and replanting for healthy forest diversification. It certainly is difficult for us to see our beautiful landscapes being marred by dead trees, but it helps some knowing that outbreaks are natural and occur every 50 years or so in areas like ours, dense with spruce.

After our two trees were cut down we had logs and limbs to deal with before warm weather arrived. The logs were fine for lumber or building, but we chose to split the wood and stacked it to dry, hoping that would be enough to kill any remaining beetles and larvae. We rented a chipper to take care of the limbs. I’d read other recommendations saying we should debark the tree or burn the bark to kill any beetles before they take flight which happens when temperatures are above 60°F, typically in mid-May through July. Neither of these options were practical for us. Besides, our neighborhood and community is currently filled with countless infested trees, so for us to go through all the trouble and expense of doing either of these methods for two trees would make little difference. We chose to expend our resources on the healthy spruce we had left.

Our two big spruce trees probably should have been taken down years before anyway for a couple reasons: wind and fire. We live in the Matanuska-Susitna Borough where windstorms are common and fire danger is often high. They were too close to our home so they could easily have caused severe damage. Another benefit to having them gone is that my yard and greenhouse will enjoy a lot more sunlight, allowing other plants, shrubs, and trees to thrive.

The Cooperative Extension Service and the US Forest Service websites have a significant amount of information about this issue and I recommend that you educate yourselves further if you are concerned about spruce trees on your property.

No items found.

Spruce Bark Beetle

Life in Alaska
Outdoors & Recreation

Author

Wendy Wesser

Writing, history, gardening, and traveling are a few of Wendy Wesser’s interests. She grew up in Alaska, living as far south as Metlakatla and as far north as Fairbanks. Her family’s history of six generations in Alaska reaches back to the Gold Rush years. She loves reading, hearing, and sharing Alaskan stories of newcomers and oldtimers alike—Last Frontier Magazine has provided her the opportunity to work in this very venue.Alternate bio for articles: Wendy currently resides in Wasilla, Alaska, but has also lived in Metlakatla, Ketchikan, Juneau, Anchorage, and Fairbanks. She enjoys sharing her life experiences of hiking, skiing, gardening, winter camping, etc…, as well as helping other Alaskans (old, new, current, or past) to share their own tales. Since she always says, “Yes!” to the next adventure, her backlog of stories is varied and almost endless. 


“Oh no, we have a problem,” I said to my husband last summer. “Our two tallest spruce trees are dying! The spruce bark beetles have attacked and won.”

It seemed like one week these two trees were healthy and the next week their needles were turning red. If I’d been paying closer attention I may have noticed the tell-tale tiny holes and the red sawdust-filled pitch oozing out of their trunks. These two giants were a focal point in our yard, but they no longer looked at all attractive. Was it too late to save them? Yes, and that was okay. Several younger spruce are growing up nearby, ready to take their place. Joel with Valley Tree Service said that the trees near the dying ones he cut down would sprout up fast with the extra daylight they will receive.

Beetle-Infested Spruce

So we had our two trees cut down and got more proactive in saving the remaining spruce on our property. We have over two acres of land with several dozen spruce trees so I decided I needed to make a more thorough survey of the remaining ones. I was surprised to find another large dead spruce with brown needles, but so far the rest are looking good, probably because they are much younger than the three we lost.

“Oh no, we have a problem,”

Back in the 1990s we lived on the hillside in Anchorage, when the Kenai Peninsula was devastated by spruce bark beetles and lost millions of trees. I was taking a master gardener course through the Cooperative Extension Service at the time and one of the hot topics was how to protect the spruce in Anchorage. A gentleman in the class had property near Kenai and he stated that he hadn’t lost one tree. We were all very surprised at his claim and a little dubious. Wow! How did he do that when so many spruce on the Peninsula had been killed in just a few years? He said that every spring he scatters 8-32-16 granular fertilizer around the base of each spruce.

I followed this man’s advice on my half-acre Anchorage property and then a few years later on our land in Wasilla. Until last summer we didn’t lose one tree. I did not fertilize my trees in the last couple years when I should have. After doing some research and confirming with Jesse Moan of the UAF Cooperative Extension Service, we are going to try that method again. She said we should keep our nitrogen below 15 to prevent causing other problems. First we will make sure our trees are not suffering from drought and then we’ll apply the fertilizer. Because the spruce bark beetles are looking for new host trees from May through July, this is a good time to water and fertilize healthy spruce. Use the amount recommended on the fertilizer package you buy. There are no guarantees that this will work, but it’s worth a try for the spruce near our home.

Another option for some is spraying high-value trees, but that is not a consideration for us. There are a lot of reasons we won’t spray our trees: we live near a lake, we have grandkids, and we don’t want to risk harming the birds, bees, dogs, cats, and wild animals that live and wander on our property.

A couple other recommended things that we will do next fall is to thin some of our remaining spruce and trim off the lower limbs. It is important to wait until the spruce bark beetles are done flying before doing these activities, unless you want to attract more of them to your property. I’m going to wait until September to be sure.

Many people don’t know that spruce bark beetles are native to Alaska and not an introduced pest. They have been here as long as spruce trees, are a natural part of a healthy ecosystem, and they help decompose weaker trees to make room for healthier habitat. Once the female beetles successfully enter a tree, using pheromones, they invite their male friends and other females to join them. Just one of these ¼” beetles can lay well over 100 eggs after boring its way into a tree. They, along with their offspring, will live, mate, dine, and spend the winter under the bark until they head off to another tree. They are just doing the job that they’ve been responsible for long before humans came on the scene.

Spruce Beetle Larva

Every few decades the spruce bark beetles get out of hand like they are now in the Matanuska and Susitna River Drainages. Why now? The probable cause is the severe wind storm in the fall of 2012 that took down many trees and a couple of hot dry summers since then. Those events may have stressed the spruce tree population and signaled the beetles that their services were needed. According to a chart I found on the United States Department of Agriculture Forest Service website, in 2015 the number of acres attacked statewide was 33,000. By 2018, that number rose to 593,000 acres. This year the number is projected to go over a million acres.

How much should we be doing or not doing to curtail the spruce bark beetle activity is a subject that is debated among professionals. So don’t get too upset with your neighbor if they don’t take care of their trees the way you think they should. Some say we should do all we can to stop the beetle damage and others say let Mother Nature do her job and let’s spend our resources on other pressing needs like firebreaks to protect communities and replanting for healthy forest diversification. It certainly is difficult for us to see our beautiful landscapes being marred by dead trees, but it helps some knowing that outbreaks are natural and occur every 50 years or so in areas like ours, dense with spruce.

After our two trees were cut down we had logs and limbs to deal with before warm weather arrived. The logs were fine for lumber or building, but we chose to split the wood and stacked it to dry, hoping that would be enough to kill any remaining beetles and larvae. We rented a chipper to take care of the limbs. I’d read other recommendations saying we should debark the tree or burn the bark to kill any beetles before they take flight which happens when temperatures are above 60°F, typically in mid-May through July. Neither of these options were practical for us. Besides, our neighborhood and community is currently filled with countless infested trees, so for us to go through all the trouble and expense of doing either of these methods for two trees would make little difference. We chose to expend our resources on the healthy spruce we had left.

Our two big spruce trees probably should have been taken down years before anyway for a couple reasons: wind and fire. We live in the Matanuska-Susitna Borough where windstorms are common and fire danger is often high. They were too close to our home so they could easily have caused severe damage. Another benefit to having them gone is that my yard and greenhouse will enjoy a lot more sunlight, allowing other plants, shrubs, and trees to thrive.

The Cooperative Extension Service and the US Forest Service websites have a significant amount of information about this issue and I recommend that you educate yourselves further if you are concerned about spruce trees on your property.

No items found.

Author

Wendy Wesser

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