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Why are ponderosa pines dying in Rogue River? #856345

Asked December 13, 2023, 5:00 PM EST

I live near Rogue River in a small mobile home park on 140 acres. The park is covered by ponderosa pines, douglas firs and many planted speciality trees (redwood, cedars, etc.). Next to my home is a pine forest with new (2023) dead or dying pines. It happened so quickly, that I missed the extent of the dying off until we had some trees removed for safety. One pines (23" diameter) needles died from the bottom up in six months this summer. We assume it was due to a change in available water, as a badly leaking irrigation canal was patched, so no more summer water. The tree did not have bark damage. BUT: this fall, 10' away, we noticed the bark was stripped from 4-5 pine trees and the dying needles were at the crowns of the trees (20-30" diameter) .A somewhat different situation. Is this possible pine bark beetle damage? Meaning irreversible damage? Meaning death? This is happening on the edge of 100-200 pine tree stand> What is the best thing for the property owners to do, to stop the spread? Is there a task force for beetle destruction? I lived in the North Lake Tahoe basin during a huge infestation and die off during the late 80's, early 90's. I can't remember how the trees were treated (removed?) Please, advise. I've attached some pictures of the trees. Thank you

Jackson County Oregon

Expert Response

Hello, yes, the trees with bark flaking have probably been attacked by the western pine beetle.  These trees will likely die.  Regarding the stand, we think that reducing density to reduce inter-tree competition is the best way to help prevent bark beetle attacks.  But our drought is making it difficult.  You may want to have a professional forester assess the stand and suggest whether thinning is needed and how much thinning would be necessary.  OSU Forestry Extension usually has a forester in Jackson/Josephine counties, but that position is vacant right now.  We hope to have it filled by 2024 winter or spring.

Here are some useful links

Info on managing stand density https://catalog.extension.oregonstate.edu/em9206/html

ODF western pine beetle management info:  https://www.oregon.gov/odf/Documents/forestbenefits/Western%20Pine%20Beetle.pdf

I hope this is helpful.
An Ask Extension Expert Replied December 15, 2023, 4:59 PM EST

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