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What causes a tree to barber chair

Discussion in 'Arborist 101' started by strtspdlx, Jul 24, 2015.

  1. acer-kid

    acer-kid Argumentative prick

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    A good trick is to make your trigger cut BELOW the bore. Far less chance of booking a flight for your husky.
     
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  2. Skeans

    Skeans Addicted to ArboristSite

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    Once in a blue you can get away with swinging a heavy leaner as well. Don't recommend it that often or that it's the safest thing to do either.[​IMG]


    Sent from my iPhone using Tapatalk
     
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  3. strtspdlx

    strtspdlx ArboristSite Guru

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    Well I bought this saw cheap. I'm not saying if it takes flight I won't be worried. I will about my safety and others. But if it sacrifices the saw and saves My life so be it. I'm just trying to learn before I make mistakes. When I was a few years younger I didn't care I would've just let the chips fly. I have too many responsibilities for that mentality now. And we're looking to buy some
    Land with about an acres worth of trees I have to clear for our horse and luckily for me they're mostly all leaning in some way shape of form. If I can get back to the property before closing I'll shoot some
    Pictures.


    Regards-Carlo
     
  4. Gologit

    Gologit Completely retired...life is good.

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    There's been some pretty good advice in this thread but I'll add just a little to it.
    A barber chair doesn't always go straight back. Sure, the majority of the time they'll split straight up the tree but they can also split out, slab out and come at you from an angle.
    When that happens the slab itself will almost always break off and come down...usually right where you'd be standing if you weren't smart enough to get the hell out of the way. It happens in the blink of an eye.



    Somebody here said that when a tree starts to 'chair that you can continue to power through the cut and maybe catch it before it gets bad. I wouldn't do that. Maybe on certain types of wood...and especially on smaller trees...it might work. Nothing I've ever cut would let you get away with that. In bigger trees with a long bar buried the action of the slab can push your bar back toward you. Again, it happens real quick.
    If you see any sign that the tree is going to chair just pull your saw and bail. You're not cutting high quality logs where trying to save one might make you some money. Even if you were it's not worth the gamble.
     
  5. TheJollyLogger

    TheJollyLogger Addicted to ArboristSite

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    Gotta jump in. At its simplest, a barber chair occurs when the gravitational force on the tension wood overwhelms the integrity of the trunk, or the cellular bond between the wood under tension and the wood under compression. The split runs up the tree until the forces equal out. At that point, whatever gravitational forces are being exerted on the crown are in complete control, and inertia takes over. At that point, conventional escape paths are no longer always safe, and quite frankly chairs often happen so explosively the concept of escape is a moot point anyway. Ya done screwed up, youre gonna take your licks. As Bob said, a mindset that the tree will only chair directly behind is false, and keep in mind very often at the end of the chair it rolls off the stob, which could be 20-30' up.
     
  6. ILikesEmGreen

    ILikesEmGreen Another crazy Poulan Fan

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    Not my post, but def enjoyed reading. Learned a lot from people with way more experience than I. It's usually cheaper that way in the long run too. Thanks guys!

    Sent from my E6782 using Tapatalk
     
  7. Gypo Logger

    Gypo Logger Timber Baron

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    I don't know why some trees chair. image.jpg
     
  8. ILikesEmGreen

    ILikesEmGreen Another crazy Poulan Fan

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    Havent the foggiest idea as to why that one did. Looks like high quality production work to me. *facepalm* hopefully that wasn't the last pic that guy ever had taken.

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  9. Gypo Logger

    Gypo Logger Timber Baron

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    Since we are talking about a very dangerous situation, I should clarify what's going on in the above pic.
    The tree was windtrown and limb bound in another tree of the same size.
    The butt was shattered already when I found it. There was nil to no chance of a formal undercut, so I severed it as best I could, then choked it off with the skidder, then completed the cut and winched it off the other tree at 90 degrees.
    If you pull the tree straight back there is always the chance that you will uproot the other tree straight towards yourself.
     
  10. ILikesEmGreen

    ILikesEmGreen Another crazy Poulan Fan

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    Ahh, that'll definitely do it. Makes much more sense than some guy trying to fell it with a single cut. More explanation on a situation like that changes everything. Lol

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  11. strtspdlx

    strtspdlx ArboristSite Guru

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    I'm glad I asked this question now. I think I'll be a bit more cautious when falling anything questionable now. If anyone has anything to add please speak up. The more I can learn the safer I'll be (hopefully).


    Regards-Carlo
     
  12. Nemus Talea

    Nemus Talea ArboristSite Operative

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    Mismatched cuts in the face can cause chairs, especially if coupled with prone species (ie. boxelder), heavy head lean, side lean, structural weakness (crack or rot), weight, wind, etc. As tree falls, the kerfs of the mismatch close and its as if there is no face removed at all.
    Borecutting works great but is best instructed in person. If you know someone qualified in its use pursue learning it, but otherwise, use previously mentioned T and triangle methods for the leaners. One of the Tube vids ya saw may have been me knocking over a goofy basswood. Not having to chase the hinge on backcut, especially on a hazard tree or bad ground is a big plus.
    Review your basics. Barberchairs should be very, very rare and not a mystery if one does occur.
     
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  13. strtspdlx

    strtspdlx ArboristSite Guru

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    Nemus
    You mention if I know of someone who knows how to bore cut correctly to have them instruct me. Why do you say that? I thought bore cuts where just notch 10%. Bore cut leaving about 1" to 1-1/2" hinge and come out to trigger and leave trigger hold if you want to use wedges. If not just release tree? Or is there a lot more to it then just that?


    Regards-Carlo
     
  14. Carburetorless

    Carburetorless ArboristSite Guru

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    Bore cuts are used on leaners to prevent barber chairing due to the tree falling before the back cut is finished.

    With the bore cut you can do a proper back cut, then release the holding wood, so the tree begins falling with a proper hinge instead of with a half finished back cut.

    I've tried using a bore cut to allow for wedges to be placed, but the tree can still set down if you take too much holding wood out before you place your wedges.
     
  15. Nemus Talea

    Nemus Talea ArboristSite Operative

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    Many variables from tree to tree and different situations. Someone looking over your shoulder can point them out better than clowns like me on the internet.
    RPM and angle at start of bore, placement of cut as dictated by ground / hazards, and body position should ideally be observed. Boring should not be used if placement results in a crack running into hinge or latch area. Bore should stop and felling plan reevaluated if large amount of rot or big cavity encountered. (large and big are relative of course) These situations can result in crushed bars, chairs or compressed stump failure. Latch shouldnt be placed in burled, knotted or compromised wood. Sapwood of some species is quite weak and must be left thicker than other trees,.. sometimes not trusted at all. Depending on anticipated tension at latch, dont place above profound buttress root as it could tear right to the ground before you're ready and root can get you. Bark, no matter how thick, should not be considered latch thickness. Bark should be removed at placement areas with axe if preloading with wedges.
    Triangle cut that gologit posted is good choice in weak and brittle stuff.
    1 - 1.5" hinge would be a bit thin at 30"+ DBH for many species. Some may be being removed if yer cutting during its fall though. Be careful of beginner manual ratios for face angle, depth, backcut height and hinge ratios. Use them as you learn but be mindful of their effects. A little rot changes hinge thickness. On cottonwood, for example, I prefer deeper face, and higher backcut than if i was taking a hickory,.. most of the time. Most manuals dont fully explore effects, good and bad, of techniques.
    If you are new or relearning methods, as I had to do many years ago, keep your brain in gear and think about the physics involved in getting that tree on the ground safely.
    Practice borecut on felled trees to get "feel" for it. Boring is actually very useful releasing stress when cutting log length.
    Got pics of stumps? A scrench, saw, cigarette lighter or pop can next to it will help for scale.
    What size saw are you working with? Bar lenth? Sharp?
    This chairing mystery must be figured out before ya get killed. Are your face cuts meeting perfectly? A kerf cut beyond intersection in face could be the culprit.
     
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  16. strtspdlx

    strtspdlx ArboristSite Guru

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    Nemus

    ALOT of info in that post. Makes me feel very ignorant to think it's so simple. This weekend I should be out in the woods weather permitting and I'll try to get a few shots of what I'm dealing with. Most of the trees I cut I had my 385xp with 24b&c the chain on the saw however had seen some metal at some point and I could never get it sharpened the way I wanted. I would call it sharp though as after I fell and bucked one tree is have to touch it up before felling anything again. Right now I sold that saw like a moron and got myself a 455 rancher. Looking for a 372xp at the moment though.
    As for my face cuts. As far as I can tell they meet very well. Nothing in the intersection point and I always had a nice straight line so I could use the felling lines on the saw.
    When you say a kerf cut beyond the intersection. Does that mean if I where to go beyond the root of the hinge and cut further back without opening the hinge more? If so I may have done that but at the most it would've been height of the chain deep. As I always tried to keep the intersection point as debri free and sharp as possible.


    Regards-Carlo
     
  17. Nemus Talea

    Nemus Talea ArboristSite Operative

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    The concept is simple, but as with all tree work, consequences for some details not addressed are dangerous.
    372 would be excellent for the job. Depending on species, 455 may be a little slow/weak with bar fully buried. Small bites like whats possible with T method would be smart way to go on the leaners.
     
  18. SteveSr

    SteveSr Addicted to ArboristSite

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    Carlo,

    I am a USFS and S212 trained volunteer sawyer. I do trail construction and maintenance. Here is what I have been taught and slightly modified to increase my safety when falling trees. This is especially useful in situations with trees with high lean, weight, or ice storm damage.

    1. Use an open face notch. An open face notch is 90 degrees or greater. An open face notch CANNOT close and cause the trunk to shatter before the trunk is on the ground.

    2. The notch depth should be 20-25% of the trunk diameter. Cleanup any "dutchman" (cut mismatch) that was formed while cutting the notch.

    3. The hinge width should be about 10% of the trunk diameter.

    4. Construct the hinge by bore cutting behind the CENTER of the notch. A swamper observer is useful to make sure that the bore cut is level with the notch. You can TAKE YOUR TIME doing this as the tree is still supported by the hinge and the remainder of the trunk. Unlike a conventional back cut the tree goes nowhere... yet.

    5. Once the hinge width is properly set I will cut the holding wood from the inside (hinge) straight back. Eventually there will be enough room to insert wedges on each side of the cut to prevent any sit-back.

    6. Cut most of the trunk but leave about an inch of what is called "holding wood". Withdraw the saw from the cut and re-position wedges as necessary.

    7. Now cut the holding wood from the outside. If the tree has any weight or lean it should start falling. If not start hammering wedges.

    The beauty of this method is that the hinge is COMPLETELY constructed first so that even if the holding wood pulls out before you have a chance to cut it, the trunk itself should NOT split and the tree will just fall in its intended direction.

    This method works great for trees that are smaller diameter than the length of your bar. If the bar is almost long enough you can slab both sides of the trunk to fix this. For trees much bigger than your bar length you have to use techniques that were shown in a previous post in this thread. The main idea is to ALWAYS construct the notch and hinge FIRST!

    Stay safe out there... Know when to walk away!

    Steve
     
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  19. HuskStihl

    HuskStihl Chairin'em for the sound

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    Nice poast. I will add to be careful with hinge thickness while setting up with a bore cut in a good leaner (especially in a chair-y species). If u'r hinge is too thick, you can still chair the tree right up the back side of the hinge. If you have to wedge over a tree with a good lean, you have way too much hinge, and the wedging will further increase the chance of chairing. I probably would not leave 3" of holding wood in a 30" aspen, but would have no problem leaving that much in a yellow pine.
     
  20. SteveSr

    SteveSr Addicted to ArboristSite

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    I believe that you meant to say 3" HINGE in 30" aspen.

    I should have noted that these are GENERAL GUIDELINES and as you have pointed out hinge thickness can vary with species, tree size, and trunk condition.
     

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