# Hollow Tree



## Rydaddy (Jan 29, 2007)

Do any of you have any real-world experience cutting down trees that have a hollow section right where you need to make your felling cuts? I realize that without being right there in front of it you can't make all of the necessary judgement calls... But, if you can give me some input as how best to notch and then back-cut this sucker that would be great. If it helps, if the tree wasn't hollow it would most likely drop exactly as it should. But this hollow issue has me second guessing the process. I do have the ability to get a tractor and a very "expensive" rope tied off to it to help with the direction of fall. It is about 30" in diam. My assumption is that I there is no gauruntee that I am going to have any holding wood where I need it.

Thanks!!!


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## winchman (Jan 29, 2007)

*rydaddy,*

if i understand you correctly, the tree in question can fall where it already is leaning - you just need advice on how deep and how to go about making the face cut etc.
i have plenty of experience (several years) of cutting down hollowed out and rotten trees, sometimes pulling them slightly different directions than what they want to go on their own. also arbor-master trained (level I).
cutting a hollow tree is not much different than cutting a solid tree, as long as the hollow is on the inside of the tree. sounds intuitive, but if the tree is rotting from the outside, more caution must be taken, because the hinge you create by cutting the face, then back-cutting, or plunging, depends on the outside of the tree, not the inside. someone illuminated this concept for me by explaining the hinge as a door hinge. if you hang a door with the hinge in the middle, it will sway back and forth. you hang a door with a hinge on the top and bottom, it has much more control and is much stronger.
after the hinge idea is understood, the first rule is no more than 1/3 the diameter of the tree for the depth of the facecut. put some tension on the pull-line (with you away from the tree in case a hanger goes loose), then back-cut until you are pretty sure a little more tension would pull the tree down. 
hopefully some of this is helpful - i have more suggestions but want to make sure i am near what you need to know before i post more.


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## Rydaddy (Jan 29, 2007)

*Cool.*

Thanks! That was basically my plan. Just a little concerned about how the "hollow" factor was going to influence the cut.


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## adkranger (Jan 29, 2007)

I would concur w/Winchman's assessment, from afar. I've felled many hollow trees as well. As long as you assess the tree's structure well, where you CAN fall it and leave a little phatter hinge wood(appropriate to size of hollow/punk wood) you can fall 'em just fine. Don't take too much hinge wood too fast, git 'er close then whittle a little till you think she'll go.

Also, I'd leave the tractor in the shed and use a high tag line. Using great lateral force against the butt puts too much lateral strain on hinge wood, could lead to hinge failure and tree falls where it wants. If you've got the rope and can get it up on the stem, use it, its safer IMHO. Good luck and be safe out there.

Oops, just re-read your post. You're planning to use the tractor as an anchor? That's ok, just pull slow and even tension, then let the rope's elasticity do the work. Sorry.


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## booboo (Jan 29, 2007)

I've had very good experiences using a slightly different wedging technique on hollow trees and also on trees with decay. Assuming a solid cylinder with no major structural defects where the notch and back-cut are going to be and also a fairly small area of good wood compared to the hollow/decayed area, maybe a 25% to 75% ratio of good wood to hollow/decay. I'll make the notch the same as normal, except that I want to actually have the center of the notch a little bit into to hollow area. If that means making the notch a bit deeper than normal, then OK. I don't want to not know how much good wood is between the center of the notch and the hollow area, that's the reason for cutting into to hollow a bit.

I'll start the back-cut normally, but then back it up with 2 wedges. 1 goes on each side of the back cut, in the column of good wood on the outside of the cut, instead of wedges in the center like normal. I don't load the wedges as much as normal but instead will alternate between tickling a little holding wood off, a couple taps on the wedges, tickle, tap etc... until it goes. There will end up being a thicker hinge than normal. Works well with trees being pulled by rope too.

Structural defects or cavities change the equation, but the basic idea still works. 

I'm lousy with graphics, so there's no point trying to draw a picture.


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## Rydaddy (Jan 29, 2007)

*Sound Advice*

Thanks for all the advise guys... as always very appreciated!


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## minderaser66 (Jan 29, 2007)

unless its got some crazy lean to it just notch it like you normally would and leave more of a hinge. if you cant pull it over by hand , tie it to your truck/car/quad/snowmobile and yank it over. lol


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## smokechase II (Jan 30, 2007)

*hollow trees safety*

Good advice from above;

I think you might want to:
1) Make sure you have plumb bobbed the lean exactly and fall it with the lean.
2) Exercise caution on not pinching the bar.
3) See if you can move slightly up and down on the stem for your felling cuts, this to get to more solid wood.

There are a lot of caveats on how much rot is present and where it is at and if there are gaps, (cat faces) in the rot that extend to the exterior.

Best advice from a group like us we'll be to post a few photos.


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## TheTreeSpyder (Jan 30, 2007)

In the imagery of cutting a healthy tree; think of the center spans between the outside regions as neither compressed nor stretched/tensioned; but rather a leveraged distance between compression and tension.

Evaluate the wood in face and hinge for stiff push on compression function and elastic on tension function. Also need solid push pieces in rear if wedging. Then, see as these guys say; the hollow tree with good outer diameter is about the same as felling solid tree, because you don't use the center mostly anyway, it is just leveraged distance spanning between tension and compression.

There was a study that if you take 50% of the core out and not violate the outer diameter 50%; the strength loss was only 6%. The outer diameter rules as the most leveraged opposing positions possible in the shape of the tree stump/face/hinge. If stuff is decayed and you lose firm push/compression where it is needed on outer diameter(nearest lean), then there is a change/possible problem; if dead/dry/froze etc. and loss of elasticity in tension (opposite lean) fibers in outer diameter, then there is a possible problem. But can have dead/froze/dry but solid enough for push, but not elastic enough for tension/pull fibers; rotted weakens the solid function response, not necessarily dead etc.


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