Are you pounding wedges, using ropes, or both? And what are you pulling with... the noticeable advantage to gutting the hinge requires a lot of pulling force. 3 guys on a rope isn't going to cut it
brilliant!!! it could be that the empty space allows even more flexibility in the posts... probably insignificant, but fun to think about...
Davidwyby, glad you discovered the monotonic teacher voice nerd videos. I really appreciate when a guy like that makes the effort and has good quality. I watched his whole series some years ago
On the stress neutral axis - its a dividing line, not a region. So it's actually a mistake to call a central (e.g. 1/3) region neutral. Whatever you cut out is either tension or compression and in his assumptions case linearly distributed per his earlier diagrams. Depending on the amount of side lean locates the axis line. And cutting central wood out adds that previously located-there load/stress to the remaining wood.
Some observations from his videos are that in compression you have headroom safety method from the crushed fibers still having compressive strength due to geometry. On the other hand if you start breaking tensioned fibers when right at the tensile limit you immediately overload the remaining tension fibers which in turn fail leading to a cascading catastrophic failure - "losing the hinge". And the tension fibers are what restrains the tree from swatting the targets under the side lean. Guess what wedges contribute? tension. Pulling contributes compression. A possibly useful insight.
He goofed a bit on kick back by citing only impact with another tree as the cause. The basic cause is that during the fell you're taking the CofG of the tree/spar from above the stump and shoving it sideways to laying-on-the-ground position - and giving it enough such shove to develop sideways kinetic energy to boot! Where does that shove come through? The hinge. edit - hockey stick or broom handle vertical on your ice rink - tilt it a bit and watch the base (with no restraining hinge) scoot out sideways!
His next video IIRC explains the crush/tensile failure during fell and is the basis for my earlier comment about diminishing returns by swapping out central hinge load bearing for fatter hinge posts - the fatter the posts the more strain per degree (directly!) of trunk fell and the more fiber failure.
It is an idea to back up a possible tension post failure with retaining the central hinge - statistics and freak failures
Daniel have you ever taken a tree to the point of experience, a failing tension post? What factor of safety do you figure you operate at? x1.5, x3 x 5 or? I'm guessing substantial if you've never popped a post in tension.
Have you ever been able to get him to interact?
no, I don't think I have even left any comments
You could be his disciple, or maybe his twin... "tree nerds"Davidwyby, glad you discovered the monotonic teacher voice nerd videos. I really appreciate when a guy like that makes the effort and has good quality. I watched his whole series some years ago
Daniel have you ever taken a tree to the point of experience, a failing tension post? What factor of safety do you figure you operate at? x1.5, x3 x 5 or? I'm guessing substantial if you've never popped a post in tension.
Hale is not perfect (by a lot in some areas) but this is one case where I'd give him a pass on the details. His basic point is valid in a practical sense, though technically incorrect as you point out. The practical point is that it's not a 1:1 trade-off. The little bit of side-holding ability you get per square inch of hinge in the middle (near-balanced area between tension and compression sides of the hinge) is far less than you get out of a square inch of hinge near the corner of tension.
I don't think so. If I have, it was backed up with a retainer line. I know I have heard hinges pop before. That's how you know you would have lost the tree without the retainer line, which is a great way to learn how much you can trust a hinge in that given scenario. I AM pretty sure I would have remembered if any of those times were using a center plunge.
The risks I AM willing to take are inversely proportionate to the value of the objects at risk. I was 50-50 (or less) on the dead oak in the above video. You can't really tell from the video just how heavy that tree was leaning. I would never have made the cut without a guy line if there was valuable property at risk. I was actually surprised that it held.
Here's a video on pulling trees with ropes from Terry Hale where he analyzes the difference between pulling with dynamic vs static line, giving the example of pulling with 3/8" line from the hardware store. I don't know anyone that would use such a light light line, and then he proceeds to calculate the speed at which the rope would recoil if it snapped... that's a ridiculous exercise in geek calculations with no real world value. He's at 7 minutes and still talking about ropes before he mentions anything else. And then it's how to tie a rope to the anchor tree. He never mentions how to set the rope in the tree, the importance of height, pretensioning the line to check for movement, how to rig a 3:1 rope come along without pullies, the use of vehicles, knots etc...
