Thick hinge broke instead of bending

D

dmonn

Branched out member
Location
Port Washington Wisconsin
I work solo and cautiously.

I was working on a dead ash tree a couple of days ago (30 inch DBH?) and had a challenging branch to remove. The owner (my stepson) wants to leave a tall stem for the woodpeckers to beat on instead of beating on his house. Since it's a dead ash I don't want to climb above the main trunk. I've been putting pull lines high up and breaking off the upper parts of the limbs to get them short enough to drop what's left. There was a 30 foot branch leaning toward the house, and maybe 20 feet from the house. I tried breaking it off by pulling, but couldn't get it to break with a rope puller x 2:1 MA. I put about 2000 pounds of force on it and couldn't get it to go.

I decided to climb to the top of the main trunk and cut it about 5 feet above the union. I did a regular face cut (50+ degree angle) and a back cut that left about a 3 inch thick hinge. The cuts were perpendicular to the lean, and the pull line was still up high on the limb. I left the hinge thick to make sure it didn't come down while I was still in the tree, and to make sure it didn't fall in the direction of the lean (toward the house). I had butt tied the limb and put a rigging block near the union with the trunk.

I came down and started cranking on the rope puller, checking periodically to see if the back cut had started opening up. I heard some cracking, but no noticeable opening of the back cut. I finally heard a loud crack and the limb came down. My stepson did a video, and when I looked at it it seemed like the hinge just snapped suddenly. Because of all the tension on the pull line (probably more than 1000 pounds) the limb came down in the direction of pull and easily cleared the house.

Bottom line: The dead ash wood might be reasonably strong, but super brittle and unpredictable. The hinge that broke was about 3 x 8 inches. (the video is too big to send to me, so I'll have to do some messing around with it before I can post it somewhere. Maybe YouTube).
 
southsoundtree said:
Maybe people should rent you a lift for dead ash.

Ask them to get a few estimates if they bawk. They will be ready to rent, I think.
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I work for free, and only for family and very good friends. I like the challenge of working without "production" equipment. The result is that I'm super slow. I also get to pick my days based on the weather. Windy days I go kiteboarding, and calm days I play in the trees. It's nice being retired.
 
That's pretty much standard for any wood that's been dead for very long at all, you can try to hinge it to fall sideways but never do it if you and the homeowner aren't ok with it deciding to break off and fall straight down.
 
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Would you have been safer if you had taken some of the tension off of the piece? Seems like it to me, especially if you intended to get down from the tree before pulling it over.
 
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Sorry if I’m getting off topic, but if woodpeckers are beating up his house, that might be indicative of a much more serious problem. Consultation with a reputable exterminator might be in order.
 
Pulling on a large hinge like that could cause the limb to barber chair (same for a standing tree you want to pull over). This could potentially cause the limb to exit the knot you have tied in to the end of the rigging line depending on what you used. I would guess that if you look at the butt end of the limb, you'll see a separation of fiber going down the length of the limb starting at the notch...like you would see if you were splitting firewood.

edit: Dead ash is crazy unpredictable. Hard to tell what kind of internal wood you have until you make a notch and can see if there is any fungal breakdown. Other issue is just total root rot. Putting two tons of force on a large limb...might make it fail at the base of the tree. Many people have a "I don't climb dead ash no matter what" policy.
 
Jonny said:
Sorry if I’m getting off topic, but if woodpeckers are beating up his house, that might be indicative of a much more serious problem. Consultation with a reputable exterminator might be in order.
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They had done some damage to his deck, where there WERE some issues that he has addressed. Good point though. He's a critter lover and mostly wants to provide good wildlife habitat while eliminating hazards to his house.
 
Phil said:
Pulling on a large hinge like that could cause the limb to barber chair (same for a standing tree you want to pull over). This could potentially cause the limb to exit the knot you have tied in to the end of the rigging line depending on what you used. I would guess that if you look at the butt end of the limb, you'll see a separation of fiber going down the length of the limb starting at the notch...like you would see if you were splitting firewood.
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Thanks for the info. I will look for that the next time I am there.
 
Phil said:
...

edit: Dead ash is crazy unpredictable. Hard to tell what kind of internal wood you have until you make a notch and can see if there is any fungal breakdown. Other issue is just total root rot. Putting two tons of force on a large limb...might make it fail at the base of the tree. Many people have a "I don't climb dead ash no matter what" policy.
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This.

Yeah, there's other stuff to be learned here...but dead ash just doesn't behave how it should and it doesn't misbehave consistently. As soon as I started reading the OP and saw "dead ash" my mind said 'of course it didn't go like you'd expect'.
 
dmonn said:
They had done some damage to his deck, where there WERE some issues that he has addressed. Good point though. He's a critter lover and mostly wants to provide good wildlife habitat while eliminating hazards to his house.
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Just a heads up on woodpecker behavior… the males drum on wood to declare their territory. Anything that makes a loud resonant tone is good and the side of a house can make a great drum.
-AJ
 
I've seen woodpeckers opening up the tunnels that carpenter bees make. That leaves an unsightly gash in the wood that's a lot harder to fix than the round hole the bees make.
 
@dmonn one major thing hasn't really been discussed; the relationship between back cut, hinge, and pull.
So let's pretend it was a healthy Red Oak we were cutting. Hinge works by severing enough fibers for the stem to go over, while leaving enough for these fibers to have control of the fall to some degree.
The hinge left must allow for the tipping over of the center of mass (whether its a horizontal limb rigged to swing sidewayS, a piece lifted up, or an upright felled over). So if you cut too much, the hinge is sevea.amd gravity takes over the center of the mass.
The same happens if the back cut is stopped early and the remain hinge needs to be BROKEN to tip the piece. If one has to over come the remaining fibers by pulling WITHOUT cutting, you are going to blow your hinge out and gravity will be in control.
Let's use for example a back leaning tree, leaning 180*s to the lay. If the cutting g leaves excessive hinge so they can move from the cutting zone, and the pull has to break the hinge to pull the weight over center, it's probably not going to make it and teeter over out of the desired lay. If one were to "stay in the pocket" sort of speak, and cut a bit, pull a bit, cut a bit and pull a bit, until the center of mass has gone over center towards the desired spot, then the cutting can move and allow for a full on pull.
3 parts : back cut, remaining hinge, pull strength at the appropriate time
 
Similar to what you're saying @CutHighnLetFly I always cut those close to horizontal branches in trying to hinge so the face is facing slightly down so the hinge is still working with gravity so the branch is falling down and to the side with the cut. I also cut my hinge a little thinner on the bottom to help prevent the top from breaking off but allowing it to swing easily.
 
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