Question for Western Foresters

[Customweld]

I’ve got a question for you western foresters. 6-8 years ago Tussock Moths went through my area of SW Idaho pretty bad. When they infected the tree, it basically defoliated them. Fast forward to now,these trees(red fir) are still standing dead but the bark never slipped on them so they are rotten. I’ve cut a lot of firewood and logged in my early years but can’t figure out why the bark never slipped on these. Normally when the tree dies, the needles turn red and the tree dries out. These tree lost their needles and never regrew them but didn’t really dry out either.
What causes the moth killed trees to retain moisture and not shed their bark?

 

[N.ID7803]

I’ve got a question for you western foresters. 6-8 years ago Tussock Moths went through my area of SW Idaho pretty bad. When they infected the tree, it basically defoliated them. Fast forward to now,these trees(red fir) are still standing dead but the bark never slipped on them so they are rotten. I’ve cut a lot of firewood and logged in my early years but can’t figure out why the bark never slipped on these. Normally when the tree dies, the needles turn red and the tree dries out. These tree lost their needles and never regrew them but didn’t really dry out either.
What causes the moth killed trees to retain moisture and not shed their bark?

Maybe its more of a root rot issue(Armillaria) that killed it and the moths just finished it off. Root rot is pretty common in doug fir. Often times their is an underlying issue, and the moth or beetle takes advantage of the already weakened tree.

 

[Customweld]

Maybe its more of a root rot issue(Armillaria) that killed it and the moths just finished it off. Root rot is pretty common in doug fir. Often times their is an underlying issue, and the moth or beetle takes advantage of the already weakened tree.

Thanks for the response. I found a really nice fir on Saturday. It looked like it was probably one of the mass casualties of the moth infestation 6 or 8 years ago. I pulled the face cut and the wedge was fine, had a little bit of punk on the outside. It hit the ground and broke into a dozen pieces, the first 2 feet of the tree were solid, but rotten for the rest of the way. I cut 2 last summer that were the same exact way. It's weird that the bark never slipped.

 

[wapitibob]

Beetles cut off the food supply thru the cambium layer and leave voids and dust trails under the bark. I would guess that has a lot to do with it.

 

[Customweld]

Beetles cut off the food supply thru the cambium layer and leave voids and dust trails under the bark. I would guess that has a lot to do with it.

I bet you're right.

 

[wowzers]

I can weigh in more later but I would suspect it’s two fold. The tussock mouth weakened them and other issues finished them off. Is DF Beetle present where you are?

Are there galleries like the ones in this link?

What's Killing The Douglas Fir? - MSU Extension | Montana State University

www.montana.edu

 

[Customweld]

I can weigh in more later but I would suspect it’s two fold. The tussock mouth weakened them and other issues finished them off. Is DF Beetle present where you are?

DF beetles are present down here. I didn't see any of the beetle trails under the bark, but ants had definitely taken up residency. That Tussock moth outbreak did incredible damage down here. The Lava Fire in 2024 burnt over 100k acres, fueled by moth killed DF and white fir.

 

[RockAndSage]

Thanks for the response. I found a really nice fir on Saturday. It looked like it was probably one of the mass casualties of the moth infestation 6 or 8 years ago. I pulled the face cut and the wedge was fine, had a little bit of punk on the outside. It hit the ground and broke into a dozen pieces, the first 2 feet of the tree were solid, but rotten for the rest of the way. I cut 2 last summer that were the same exact way. It's weird that the bark never slipped.

Man, that sounds like it's starting to be some pretty dangerous stuff to fell - is that kind of breaking apart common with that afflicted timber?

 

[Customweld]

Man, that sounds like it's starting to be some pretty dangerous stuff to fell - is that kind of breaking apart common with that afflicted timber?

It probably is common with that type of mortality, I've just haven't encountered it. Like I said earlier, this was a huge kill off, so these trees are everywhere. I spend a lot of time up this area and have a pretty good idea on which trees were a part of it. As much as I hate to leave a good, standing snag, I think I'll look for different wood patches.