Thanks, Joe. That is my hope and was my motivation for making the videos. My fear is that a lot of those novices are inappropriately confident and don't feel the need to research something that they see as a simple action.

Thanks, Bobby. I've urged a couple of the more mainstream arborist sites to go ahead and produce a series of educational videos specifically to orient ground crews on safety, hardware, etc. It would be a big undertaking and no takers yet. I feel it would be a really useful series. One company has put some videos together, but more is needed.

Thanks for that!

Mark, Years ago, my wife and I made a hike to Lake Quinault and cherished the experience. I can absolutely appreciate your choice. Nice!

You have my permission to watch it several times. lol.

Shouldn't the notch be cut deeper than the tree's vertical CG? Seems to me that is the only way for the tree to not pinch the back cut without wedges, winching, etc.

You don't have control over (and usually don't know) where the c.g is. You pick a direction to fell the tree in and make the hinge perpendicular to it. It's best to keep that hinge towards the side you want to fell it in. If you cut it too deep, you may have guessed wrong on where the c.g. is. The extra width for the back cut gives you better options to use wedges.

Thanks Steve.

the victorious yamani eo

Thanks G. Sometimes it's nice to get confirmation of why your practices are good.

Much appreciated Max.

Thank you, John!

Thanks Andrew!

Thanks Alex. For almost two months, KZfaq was hiding comments from me. I finally discovered that last weekend and began responding to them. Yours "required" the lengthiest response I have yet attempted. I was a few lines shy of sending it when it suddenly converted into a tiny electromagnetic puff of heat. Needless to say, I was quietly, but highly, pissed off. It gave me an aversion to trying again until tonight. If this attempt also disappears into the ether, you will hear the explosion and have no idea what that was. In answer to your question, I am practically certain there is no such formula. However, a mathematically true, but physically flawed, formula can be worked out. First, we have to define some variables. Let Ht be the height of the tree in feet. Let Kw be the width of the kerf for your back cut. (Assume 3/8") Let Ww be the width of your wedge measured in inches, right at the point where it enters the wood of the trunk. Let Ma be the moment arm, measured from that same point, perpendicularly to the effective center of the hinge you have cut. Let Tm be what you want to find, the feet of movement at the top of the tree. Given those variables, the theoretical formula would be: Tm = Ht x ((Ww - Kw)/Ma) As an example, say you have a 70 foot tall pine tree (Ht = 70) Say the distance from where you wedge enters the trunk to your hinge is 7" (Ma = 7) Say your wedge is 1" thick at the end, but you have only driven it in to where it is 3/4" thick. (Ww = 3/4). Remember that 3/8" of that is "wasted" just replacing the wood you removed making your kerf. Applying the formula, we get: Tm = 70' x ((3/4 - 3/8)/7) or Tm = 10' x 3/8 = 3'-9" Unfortunately, this ignores some physical issues. The most important one is that wood is not inelastic. Prior to your cutting and wedging, the weight of the tree was supported by the entire area of the cross section. Due to your vicious attack, that weight is now supported only by the hinge and your wedge. Given that you are needing to wedge it, the pressure that the wedge is exerting on the wood is quite a bit higher then the pressure on the hinge wood. As a result, the wood at the hinge compresses somewhat and the lift is reduced. The movement at the top might be reduced by half. You can, however, improve the situation by driving additional wedges. With three wedges, the stress on the wood at each will be reduced to about a third of what the one was feeling and you will get closer to your theoretical lift. The compressibility of the wood will vary significantly with species, density, moisture content, and any rot.

thank you very much for your answer it is a great help. when felling in tight situations I like to roughly work out all possibilities by measuring the tree size and I always wondered if it was possible to to figure out how much lift I would have to produce on a back leaning tree to tip the balance.

Alex Beedie Ah! So it was not just idle curiosity. ; )

You warm my heart, as your are my target audience. I hope you have a fireplace as dead standing ash is a great firewood. If forest grown, it splits really well. Not a bad guess, but I'm a civil engineer and computer programmer. I do love to teach. I hope all the removals go well for you!

Certainly! Also, feel free to copy any of the content you want. Bless you for your efforts to help other people.

Keith, You pretty much nailed it with "there's probably no such thing as a perfectly balanced tree". If the tree is well balanced, cutting 1/3 of the way through is likely to make it lean a bit to that side. After all, in theory, the full width of the trunk is under compression from the weight of the tree and you just removed the support on that side. With a well-balanced tree, a wedge is typically not needed. Even with a lot of experience, what looks like a well-balanced tree can trick you. I'd say the 1/3 is a reasonable ballpark number; certainly not something requiring precision. Considering how frequently cuts don't cooperate on where to join, the 1/3 should be viewed as little more than a target. If you cut the depth to 1/2 the diameter, you're probably doing a lot of extra cutting. Additionally, unless you're dealing with a large tree, you may be running out of space for your wedges in the back cut. If you cut to less than 1/4, your hinge length is starting to get short and you will have reduced resistance to the tree falling sideways. If you know you have to deal with a back leaner, you may want to use a shallower notch. That way, you will have a large couple (distance) between your wedge and your hinge. That will act as leverage and reduce both the stress (tension) on the hinge and stress (compression) that has to be overcome when driving your wedge in. Bottom line, all things being equal, 1/3 is a good target, but not something to get stressed over.

Your forgetting that the quality of wood can vary and if there is sn unknown rotten core, cutting a half diameter notch would be a disaster. A 1/3 notch ensures a likely good hinge

You are correct. If a cutter misjudges the tree, it could settle and squeeze tight on the chain/bar. Similarly, the tree could begin to fall before the feller is ready to do the back cut.

Thanks David. Relative to side lean, Yes, a wider hinge is safer. If lean or back lean are significant factors, it gets more complicated as removing a large notch weakens the tree's ability to resist those leans. Shallow notches are needed for leaners, as covered in "Leaners".

@@terryhale9006 very interesting; and great info. -- thanks for the instruction !!!! Have to check out that video also.

Yeah. Sorry 'bout that. I won't compete with a stream again. Also, it turned out that my camera was set to Autofocus. Works fine for still photography, but adds a bunch of noise if you're taking video.

Definitely agree. I had no idea the microphone would pick up the noise so well. Won't do that again. Unfortunately, it was only one of several sound issues I've had to work on on the videos.