I was called out to assess a leaning tree today. Dougls Fir. It has a few (3 that I could see) trunk swellings with resin flow, numerous small (1/8") borer holes in the bark and some dieback and dead branches in the canopy. I am wondering if anyone can give me input on the cause or reason for the swellings and the id of potential borers for the holes as seen. I am in the Pacific northwest and most info I can find is forestry related which doesnt help me much so far with the residentially growing trees.
Douglas Fir problems
- Thread starter jimmyq
- Start date
Help Support Arborist Forum:
If that were a tree in the southeast, I would call that a fusiform rust gall canker. Although I'm not familiar with the conifer pathogens in the PNW, I'm pretty confident that you've got some sort of stem rust infection, which are often associated with attacks by bark beetles and clearwing borers (such as pitch moths). Some of the holes in the bark in those pics look like they're probably not penetrating into the cambium. There's actually a whole set of boring insects that go through their life cycle in the outer, corky bark of mature conifers, without doing any damage to tree health.
I'm sorry to say that there's no treatment for that sort of infection, which can cause significantly reduced stem strength at that point.
I'm sorry to say that there's no treatment for that sort of infection, which can cause significantly reduced stem strength at that point.
timberbeast
ArboristSite Lurker
From my experience, a dying canopy (top) is the first sign that the cambium has been ringed by borers. At looking at the photo, the borers are near the base (within the first 2 - 3 meters), as opposed to a stem borer much further up the tree.
Unfortunately, removal is the recommended practice at this point, so as not to further promote the beetle infestation which may later fly and attack the healthy trees nearby.
I've heard of people experimenting with direct injections and such to promote vigor to encourage the trees natural ability to force the borers out. Some homeowners in a forested environment have used foilage spays to keep borers from infecting healthy trees, but with limited success. Again, once it has been ringed, that's pretty much about it.
Similar threads
