Fir tree disease vs drought - Ask Extension
Hi guys, I have a number of fir trees on my 2 acres, leftover from when the property was a Christmas tree farm. Not sure of the variety they are, sorr...
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Fir tree disease vs drought #847001
Asked August 23, 2023, 4:19 PM EDT
Hi guys, I have a number of fir trees on my 2 acres, leftover from when the property was a Christmas tree farm. Not sure of the variety they are, sorry. I am seeing many of them are exhibiting dying or dead branches on random trees and branches. Pics attached. Is this drought related or disease? And if diseased, should I cut the affected trees down to stop the spread, or is there a treatment for it? I really hate to remove any trees, but will if needed to halt this.
Marion County Oregon
Expert Response
That looks like noble fir, which is (was) a very commonly planted Xmas tree. There are lots of these stands that were planted and then abandoned. They often are suffering from multiple issues especially associated with hot dry weather we have been having.
Noble fir naturally grows at much higher elevations (3,000 ft +) so it doesn't do well with our heat and drought.
One fungus in particular can cause the branch and top dieback you are seeing, called Grovesiella Canker (Grovesiella abieticola)
Here is a link to the disease and management recommendations
https://pnwhandbooks.org/plantdisease/host-disease/fir-true-abies-spp-grovesiella-canker
In terms of management of the stand. Yes, you may want to remove these diseased trees and keep the best looking ones. Also, doing some general thinning to give each tree more space could also help. But in general, you have a tree that is out of place (off-site), and is not really adapted to our lower elevations. Sometimes they do fine, other times they just get battered by heat, insects and diseases.
Noble fir naturally grows at much higher elevations (3,000 ft +) so it doesn't do well with our heat and drought.
One fungus in particular can cause the branch and top dieback you are seeing, called Grovesiella Canker (Grovesiella abieticola)
Here is a link to the disease and management recommendations
https://pnwhandbooks.org/plantdisease/host-disease/fir-true-abies-spp-grovesiella-canker
In terms of management of the stand. Yes, you may want to remove these diseased trees and keep the best looking ones. Also, doing some general thinning to give each tree more space could also help. But in general, you have a tree that is out of place (off-site), and is not really adapted to our lower elevations. Sometimes they do fine, other times they just get battered by heat, insects and diseases.
