Insects living in the bark of my large Doug fir - Ask Extension
I have a large Doug fir (3' dia) within 15 feet of the house. Starting at the ground and up to about 7 feet, I noticed quite a few areas of the bark s...
Knowledgebase
Insects living in the bark of my large Doug fir #751140
Asked May 20, 2021, 4:30 PM EDT
I have a large Doug fir (3' dia) within 15 feet of the house. Starting at the ground and up to about 7 feet, I noticed quite a few areas of the bark sounded hollow. When I pulled some off, there was obvious insect damage underneath. The bark was full of small holes and insect pathways, and had turned to dust in some places. No insects, but there were a few of those white webby blobs like spiders make. How concerned should I be??
Marion County Oregon
Expert Response
If the loose bark and insect activity is confined to the bark itself, and there is not exposed wood, then there is likely not a "tree killer" insect or disease.
If there are signs of insects or rotten wood under the bark, the tree may have an old injury that is not grown over. Sometimes the insects may just be colonizing rotten wood. Not a direct health threat, but the rot may weaken the tree structurally.
A key indicator of tree health is the condition of the foliage (all the green foliage = the tree crown). If the foliage is dense and dark green and there is abundant new growth coming on, that is a good sign. Thinning foliage, yellowing, dying tops or branches, or weak new growth are all signs of health problems.
For a more complete diagnosis, I would need more information. Could you send photos? The whole tree from a distance, the base of the tree, the areas of concern on the bark.
After we get through further diagnosis, if you are concerned about tree hazards from a tree near a home, you should contact a certified arborist for a formal hazard tree assessment. https://www.treesaregood.org/findanarborist/findanarborist
If there are signs of insects or rotten wood under the bark, the tree may have an old injury that is not grown over. Sometimes the insects may just be colonizing rotten wood. Not a direct health threat, but the rot may weaken the tree structurally.
A key indicator of tree health is the condition of the foliage (all the green foliage = the tree crown). If the foliage is dense and dark green and there is abundant new growth coming on, that is a good sign. Thinning foliage, yellowing, dying tops or branches, or weak new growth are all signs of health problems.
For a more complete diagnosis, I would need more information. Could you send photos? The whole tree from a distance, the base of the tree, the areas of concern on the bark.
After we get through further diagnosis, if you are concerned about tree hazards from a tree near a home, you should contact a certified arborist for a formal hazard tree assessment. https://www.treesaregood.org/findanarborist/findanarborist
I couldn’t really get a picture of the top of the tree, but it is as tall as other Doug firs nearby, and some foliage that came down in the ice storm looked normal and healthy.
This pic is of several chunks of bark that I pulled off with very little effort laying on the ground.
This pic is of the bark of the tree, about three feet up, where I pulled off the chunks.
Thanks very much for sharing your expertise and for taking a look at the photos.
Joe
From: Ask Extension
Sent: Monday, May 24, 2021 3:00 PM
To: Joe Nickeson
Subject: Re: Insects living in the bark of my large Doug fir (#0021071)
It sounds like the crown is healthy. The bark shows signs of carpenter ant colonization under the bark. Likely there is some exposed and rotten wood from old injuries that were not completely covered over by new wood. The main issue to watch for is structural weakness due to wood rot. If the overall health remains good, the tree will continue to grow new wood that may "keep up" with the rot and help compartmentalize the rot. Again, if you have concerns about safety or property damage if the tree were to fail, consider having a hazard tree assessment by a certified arborist.
