Strength of dead ash

[dmonn]

I'm in the heart of EAB country. I'm a homeowner with 2 acres of forest, where about half to 2/3 of the trees are dead ash. I'm removing some of the more unsightly dead trees, and leaving most to decay on their own. To take down dead ash, I've been very reluctant to climb them. Most have been dead for 2 - 4 years. Good reason to not climb them, right?

To prevent damage to surrounding healthy trees, I have been breaking off the canopy branches to make the trees "skinny", so I can drop the trees into narrower spaces. I also have deliberately hung some of them against other trees so they drop piece by piece near vertically. I have also rigged removal trees to nearby trees to lower them gently and direct them away from healthy trees as they come down.

What I've found has really surprised me. Except for some smaller canopy branches, the larger branches seem to be really strong. I've pulled on 4-5" branches 10 feet from their union with the main trunk at 90 degrees to the union with 500 - 1500 pounds of static force before they'd break. They'd be bent like crazy before they'd break. That was my first "wow" about them.

The second "wow" was when I'd be pulling on a larger canopy branch, and the trunk would break just above the ground. I'm talking about 10 - 12 inch diameter at the break. That was really a big surprise to me. A 4 - 5 inch branch would bend nearly double from a perpendicular pull and not break, but the 12 inch trunk on the same tree would break from a force only 30 degrees from vertical.

Is that "weaker near the ground" something that's common for EAB-killed ash, where the large branches higher up are still very strong?

 

[ATH]

Ash get very brittle. Yes, breaking at the ground is not uncommon. I won't even think of climbing one if the bark has started coming off.

Ash Breakage: the Hazard Continues

Ash breakage is making a walk in the woods no walk in the park!

bygl.osu.edu

 

[Anawan]

‘I also have deliberately hung some of them against other trees so they drop piece by piece near vertically.’

I like that idea. And skinning them up with a throwline. I like anything that keeps you from climbing these trees. Mid trunk failure is what I see with the trees that have been dead 2 plus years. Extremely hazardous to climb.

 

[ATH]

Yeah it's funny...
The either snap off about 15 ft up or right into ground level. I've hardly seen any in the woods that are snapped at below 10 ft unless it is right at the ground

 

[dmonn]

‘I also have deliberately hung some of them against other trees so they drop piece by piece near vertically.’

I like that idea. And skinning them up with a throwline. I like anything that keeps you from climbing these trees. Mid trunk failure is what I see with the trees that have been dead 2 plus years. Extremely hazardous to climb.

Not pulling with the throw line. Pulling with 1/2 inch bull rope to handle the hundreds of pounds of force it takes. I use either major mechanical advantage (at least 10:1) with static pull or 2:1 or up to 4:1 with all the dynamic force my lawn tractor can generate. It's amazing how strong the branches can be. Even a little 2 inch branch pulling from 5 feet away from the trunk takes some oomph!

 

[chipper1]

Be careful as they can break off in the middle when dumping them into other trees and come back at you. Another thing I've seen is when you are falling them and the top or larger branches break and tip back towards the stump and you become the target. As with falling other trees in the woods you can also have dead branches get thrown right back at the base of the tree by live branches that load up in the canopy.
Be careful, many have been hurt/killed by dead ash.

 

[dmonn]

Thanks for the reminder. I usually wind up rigging a tag line to pull the tree over after cutting to a proper hinge thickness, and always use a redirect on the ground so I'm not pulling the tree straight toward me. Totally correct about how unpredictable those trees are. I flip up my earmuffs as I'm getting close to listen for anything that doesn't sound right. If I hear any cracking, I let go of the saw and run like hell. When I know I'm far enough away, I then look back to see what happened. I've cut enough of these guys to have seen how unpredictable the flying dead branches can be.

 

[CjM]

Curious why you're removing these trees over such a large area. Are they over trails or structures? Out in the forest I'd go with what the Park Service calls "benign neglect."

I've rapped off a lot of crane pics removing ash last year or two, worried about being high on stems, even just sitting still waiting for the ball to return. Sounds like you have a good handle on this though, especially with a redirected pull line. Do you know how to set up your hing and leave a trigger? I prefer that to running like hell.

On a similar note, anyone have any research on climbing treated ash? I bailed from one earlier this year that was treated in the last two years but still had lots of necrosis.

 

[dmonn]

The trees I'm cutting are mostly slight leaners that would damage healthy trees on their way down. I practice benign neglect on the rest.

I think I'm OK at setting up a trigger release, especially for significant leaners (bore cut). What I try to be aware of while I'm cutting is the unanticipated behavior of the tree. Hidden rot primarily, and in a spot I thought would be good hinge wood.