Short bar techniques.

[sawinredneck]

I've been thinking about this again and again, but the Coo's bay still bugs me to death!
Here's my problem, on a leaner, you bore to remove the heartwood to prevent a barberchair and trip the strap. On the Coo's bay, you still have a large chunk of the heartwood left, lots of wood to cut through.
Maybe I'm being more of an idiot than normal, but how is this cut eliminating enough pressure off the heartwood to prevent a barberchair? I bring this up because I've been thinking of gutting the hinge with a Coo's bay, just leaving a strap with a short bar on some larger tree's.

 

[woodworkingboy]

I would venture that with less wood still attached (side cuts), you have eliminated much of the resistance that causes the splitting and separation as the tree falls. The smaller center allows a section of wood considerably weakened compared to with the larger area still attached. Greater bendability or breakability without the larger consequences due to more wood having to yield.

Take a 2x2 for example, and whittle it down to just a small section of wood left in the middle, and compare breaking it with one with much more wood left. The amount of splitting and damage along the vertical axis increases with the larger volume of wood and resistance still left. The weight compounds the physics of the break, greater forces both vertical and horizontal as the tree goes through it's trajectory.

 

[sotc]

It's just Coos Bay

 

[gf beranek]

I was skeptical about the Coos Bay when I first heard it described to me. After much ado and eventually trying it out I found it works wonderfully.

Because it doesn't follow conventional wisdom leaves most people in wonder. And that is natural.

 

[Bermy]

Also you are severing the cambium on the sides...eliminating that fibre hold, am I right?

 

[SouthSoundTree]

I thought that the Coos Bay cut allowed the final felling back cut to be cut very fast, so less time of the tension/ compression/ internal stress changes to occur. Sorta like cutting fast can beat some barberchairs, whereas cutting a little bit at a time can allow it to happen.

Alternatively for heavy leaners, from what I recall from Gerry's pages, the back cut being cut into a triangle with the wide side of the triangle at the hinge, and a point of the triangle opposite the lay, allows the felling cut to progress much faster. Its been about 7 years since I read it though, and I was a green sawyer at the time.

What say you, Gerry?

 

[sawinredneck]

OK, is it the heartwood or the cambium that causes barberchair? I've always understood it to be the cambium, but am willing to learn.

 

[SouthSoundTree]

Wasn't there some thorough thread about the causes of BCs?

I don't know what really causes them, just some of the situations (heavy leaners, wind gusts, too forceful with a pull rope) where they occur, and some of the techniques to lessen the likelihood.

What other contributing factors are there? Too thick of a hinge?

I am very willing to learn the technicalities of it.

 

[sotc]

http://gypoclimber.com/showthread.p...-felling-cut-vs.-Burnham-s&highlight=coos+bay
http://gypoclimber.com/showthread.php?9510-That-Coos-Bay-felling-cut-again!&highlight=coos+bay

 

[stig]

OK, is it the heartwood or the cambium that causes barberchair? I've always understood it to be the cambium, but am willing to learn.

Like Bermy said, the heartwood is brittle, breaks easily, the sapwood is much more fibrous and flexible.

( Well, she didn't say it like that, but I bet that is what she meant)

So the Coos Bay works by a combination of allowing a fast backcut and laeving only the brittle heartwood to be cut.

 

[HolmenTree]

Yes I think that is what Bermy meant. The barber chair split has to start somewhere and its going to start at either outside corner of the backcut at the sapwood.
Also from experience too thick hinges in a straight grained spruce for example, can easily take off into a barberchair.

Willard.

 

[gf beranek]

The overall bad thing about using conventional face cuts in a head leaner is you are undermining the lean when sawing a face. And it just puts more tension and pressure on the wood left holding the tree. And in itself increases the chance of Barber Chair. Unless you bore the back cut a shallow face in a heavy head leaner is a sure recipe for disaster.

Ironically a deeper face can actually help minimize the chance of barber chair even in spite that it puts more tension on the remaining wood that needs to be cut. Well that is if you can get a deeper face in in such a tree. And barring defects in the stump.

And all of that is the root of the problem with conventional methods on head leaners.

How the Coos bay circumvents the problem is, well, for one it doesn't undermine the lean. And two, the remaining tension wood is just a strap instead of the whole back of the tree.

But no matter the method we choose to take on a heavy head leaner we still have to be prepared to run for our lives and in many cases not stick around to save the saw. If wood pulls in the stump the saw is usually going with it.

I don't know if that helps explain it any better. The bottom line always remains, have a good way out.



W

 

[Bermy]

Like Bermy said, the heartwood is brittle, breaks easily, the sapwood is much more fibrous and flexible.

( Well, she didn't say it like that, but I bet that is what she meant)

So the Coos Bay works by a combination of allowing a fast backcut and laeving only the brittle heartwood to be cut.

Thanks Stig...transglobal brainwave translation, awesome...!

 

[stig]

It's a special gift I have.
I once identified a bird for Terri while being halfway across the world from her

 

[Jed]

O.k. Jer I might have had a brainwave while reading this thread. I won't say "trans-continental," but then, inbreds will take what we can get. Here it is: why mess with the Coos Bay at all when we could just ream-out all the compression wood--like when you buck a big log whose top is in compression. (Especially I who have quite a difficult time lining up two cuts of any kind. I'll confess that when I've had to deal with dirty head-leaners, the idea of getting the two "side" cuts in the Coos Bay to line up well enough in order to be able to zip the remaining wood well, has proved too daunting of a prospect for me to even want to deal with. Granted, I could have made diagonals to get two pie-cuts out like the Husquvarna manual tells you to do, but I didn't think of that.

Neither one'll give ya any directional control at all right? But, of course, no one who is having to deal with that dirty of a leaner is gonna get a hair of directional control without risking a possible slab-out anyway right?

 

[woodworkingboy]

Jed, I think you just need to see trees as trees, not whether they are dirty in that context or not. It might help your powers of analysis and technique.

 

[SkwerI]

If I may interject here-
Jed, the Coos Bay is for use when there is too much head lean tension to make your standard undercut/ jump cut. You can do the entire cut without ever lifting your saw out of the cut. Start by reaching over the tree (or limb) with the saw and making the far side cut first. Then roll the saw toward you and make the near side cut. Then level the saw out and finish it off cutting like hell until it pops. It's all about being able to cut the wood fast enough to outpace the barber chair.

 

[bill22]

It also goes without saying that you should use the biggest saw available[power wise,not bar wise] to get it cut fast enough.

 

[gf beranek]

I want to live to see the days we get laser saws. Sever and run!

 

[bill22]

That would be awesome.

 

[canadiantreeman]

If you're talkin light sabers Imma all over it! May the force be with you.

 

[sierratree]

ok.............i was reading the initial post about using a short bar, then kind of morphed to the heavy head leaner topic. which is good, in itself........but getting back to a thought i have about utilizing a short bar, if i may:

short bars are fine, but if there is a heightened risk type tree; snag, heavy, etc., we really should be thinking about minimizing our exposure time at the stump. so if at all possible, use the best saw for the job so you can get in and get the hell out.

thanks for letting me diverge back, abit........

 

[gf beranek]

On the steep ground you got to have a bar that can reach through the tree. If not you put yourself in far more risky scenarios.

 

[Burnham]

No kidding...or force yourself to work on a springboard on the downhill side, which amounts to the same thing, I reckon.

 

[Al Smith]

Hmm all this time I thought you guys had one leg shorter than the other to negotiate the slopes .