split spars - pit in stomach

K

Keese

Location
upstate New York, near the Canadian border
Thought I would run this by to ease my conscience. Working alone, taking down 10 live black locust, all ~24" dbh or so, 90 footers mostly, upstate NY so ~25 degrees today, 15 - 20 mph wind gusts. I use a 2 ton come-a-long and pre-tension all my removals. Hundreds have gone perfectly. Got a new 3 ton puller with 5/16" cable because these guys were leaning ~5, 10, 15 degrees, side and back and combo leans, into the house and service wires so I wanted to make sure I had enough pull. I had a hole just big enough to drop them all into - so it was priced accordingly.

CLEAN open face notches, precise tapered hinges, wing cuts, bore cuts, wedges if indicated. Some were felled in whole and some were taken with two cuts due to space restrictions.

So, on two upper sections, ~12" diameter, the trunk split directly behind the hinge and both up and down the trunk 2 or 3 feet. One peeled down the front and the other just showed a big ugly split. No defects were noted in the stems.

My thoughts are that I pulled too much on the tag line because my hinge was too big. I left the hinges nice and healthy, 15% maybe 20% because of the lean and wind and would NOT have felt comfortable with any less of a hinge. I checked the hinges after and they looked good. I wanted to rely on the new 3 ton puller to finish the job and I didn't want the hinge to fail before I could get to the ground and crank the puller.

Has anyone seen splits like this and does anyone agree with me pulling too much? If so, what would you have done without compromising your hinge? Besides taking them in pieces.

Thanks - I read this forum a lot and you guys are amazing. I would appreciate your thoughts.

Keese
 
In the winter I've found that wood is more brittle and likely to fracture. It sounds like you did pull too hard. You didn't say so but I hope things came down all right with no injury or damage.

There is another felling technique that you should consider. I'm sure others will add their favorite name. Plunge cut is one name. Strap cut another.

Set things up like normal. The first tension is just to take the stretch out of the pullover line. Then make your face cut. Tension again to take up slack and add just a bit of pre-tension.

Make your backcut but you need to leave a strap of wood on the outside, opposite of the face. You need to make a plunge cut with the tip and work the cut towards the strap and also towards the hinge. Now you've removed all of the holding wood except for the hinge and strap. Walk WAY around and tension the pullover line just a bit.

Go back and cut the strap. Some people cut directly through the strap at the same plane as the back cut. Others will cut from the inside out. Another way is to cut the strap just a little below the back cut, making a mismatch cut.

For a better description and MUCH more information, check out Tim Ard's site:

http://www.forestapps.com/

Go to "Tim's Tips"

His eBook is a real bargain. You can pay a little bit more and be able to print things off the CD. Well worth the couple of extra dollars.
 
Tom,

Thanks. No damage and no injuries except confidence. I do use the strap of wood, I call it a trigger. I do exactly as you do when I am on the ground and walking back and forth is not a hastle. But when I'm up in the bucket 55' and I have already gone down once to set the tension you look for short cuts so I will cut my trigger with a little extra pre-tension already set. But these two pieces were too small for the trigger by the time I did my bore cut (3" notch, 2" on the tapered end of the hinge, 3" plus bar and chain) well maybe I could have left a trigger but I didn't want to make another trip up so I had to cut right through the back. But the trigger won't make a difference if I pulled too hard - will it?

I have gotten good about the tension where the piece doesn't go popping off the stem like a shot and it usually just sits there until I get to the ground and crank it over nice and easy. If it does go while I'm up there it is always nice and clean - looks like I planned it.

You are right about the brittle wood. And I am aware of compression wood and tension wood and that these locust have tension wood more than compression in response to the unbalanced stem loading. Plus the fact that I was cutting side combo leans involving both tension and normal wood fibers. But isn't that tension wood only a concern in my hinge and back cut? Do you think it would cause a split like that? I suppose if it is brittle, which tension wood is and in the winter, that it may. I wish I knew.

Thanks for your input Tom.

Keese.
 
Sounds like you're thinking about what's going on. Good...

Frozen wood reacts much different than thawed wood. I remember doing elm takedowns in Minneapolis in the winter. In the morning I'd expect to get hinges and rips but the wood popped. Then in the afternoon I'd adjust my cutting, expecting pops and the wood would stay in place. That gave me a few butt-puckers.

We have to add our experiences together since it's rare that we can practice under repeatable circumstances. It's not like welding, music and carpentry. The Oops Factor is pretty high too. Having a good mentor helps. Taking advantage of the collected knowledge of the TB gang can be part of a mentoring too.

Glad to see you here!
 
Keese,

Are you saying that you install a tagline in the top of the tree, pre-tension it, and then go back up in the bucket to pop the top out? Or are we talking about ground felling?

If you are talking about topping the trees, and you have to do it alone, then I would suggest a few other ideas. First, do what Tom says and setup the hinge first. Then, make your back cut a few inches below the hinge creating a step-cut or cross-cut. Then go down on the ground and crank the top off. This way you can use a normal sized hinge (3/4"-1.5") and not have that split happening. Also, if the tree is leaning opposite the cut, you won't need anu extra hinge. The tensioned line will keep it in place.

Am I off base here? Were you not talking about cutting the tops out? /forum/images/graemlins/confused.gif
 
Sounds like a combination of too much tension and too thick of a hinge. Very easy to do especially with a back lean. Man that's got to get scary all by your self. It's well worth the $ for a second man, even if all they do is stand by to call 911.
 
Mark,

It is both tops and ground cuts - depends on the lean and how much room I felt I had. I like your thoughts on the cut below the hinge. I have not done that and will practice in non-critical situations (like those come along every day). To be clear - do you mean I can make my bore cuts and leave my trigger all 2-3" below the apex of the notch whether it is open face, traditional or humbolt?

I do work alone and my personal life pretty much dictates that - 3 horses, 3 dogs, 3 cats, 1 wife. I run a one man show - one bucket, one crane, one chipper, one skid steer. But I get on site at 8:30ish and I'm done by 2 and I can take days to do bids, run errands and equipment maintenance. I have used interns and they are a nightmare. They swear they can do something and it's not even close. Anyway - that's a whole new thread.

I'll try Marks suggestion and see how I like it. Sounds a little funny of course because I have had so much success with traditional methods. I take everything into account - wind, terrain slope, species, etc. It sounds funny that I work alone when I am safety conscience but sometimes I think it it safer. Everything gets done my way and I don't have to wonder if he checked this or did that.

Guys around here don't even wear helmets, no eye protection either. Don't even know what kevlar is. I have full ppe, bungee harness in bucket and try to stay current.

Keese
 
Keese,

Just Nortn of you here... I think the guys might be on to something with reference to the hinge-pull ratio. I like the general application of a hinge 5-10% thick (% of diameter) and about 80% width (% of diameter). I am also REALLY shy about pre-tensioning pull lines. I got REALLY lucky with a 36" diameter Silver Maple barberchairing up 6' leaving 4" of my hinge behind. Butt pucker....understatement. I might switch from your come-along winch to a double sheave mechanical advantage setup. These are easier to set up for faster or slower pulls. More MA = slower pull.
 
Stumper recomends long narrow hinge for best flexxing from years as a bowsman artisan.

Soren Eriksson on an old Stihl tape recomended center punching face so as to use/flex only the outer, younger, more flexible fibers.

On a back leaner i bring hinge back further, to decrease the backlean as calcualted from Center of Gravity to hinge angle, givng more weight pulling the tarrget direction, and less degree of movement needed to place Center of Gravity forward of hinge.

Any dutch/shelf made by crossing bottom cut across top cut (face) immediately on mvoement of spar closes, and the more force of tree weight towards target/ wedge push/ line pull you place into system, the more that force is reflected back against you in response (pushing away from target generally). Also, the face not closing, places all the control at the back (hinge where you can adjsut with saw)) for normal felling; not much control in loaded forces in clsed face, where saw can't get to it to adjust.

But genetics and cold weather is hard to beat the brittleness of.
 
Mangoes,

Glad to meet you eh. I love Canada. Spent many of nights up there in my hay day. Thanks for the input. I'll consider the sheaves - already have all the parts I believe. I was on site today cleaning up and I inspected my stumps and butt ends closely. I found more hairline cracks indicating potential splits or maybe they were splits and just pressed back together. Regardless, this job has shaken my confidence in my technique. Not completely, I have removed many many trees this way with 99.9% accuracy in all kinds of situations. So I am inclined to blame it on species (can't remember the last black locust I removed this way) and temperature AND the first day with the new 3 ton puller.

I am changing my pre-tension routine to just enough tension to take the slack out and keep the tree from falling backwards in case I make an error up/down there and to keep the hinge in the proper percentage (even when I taper the hinge).

The owner is a lifetime logger and he removed 35 of the trees (all smaller) himself before he called me. I respect him for knowing his limits. Missing in the woods is one thing. It's funny though because I can't imagine a tree that I can't take down safely - by my perspective. I'm sure those of you not working alone gauge my limits much differently.

Keese
 
I wasn't fully reading the post. You wrote Black Locust....there might be something to be said for the species. I was once told that lumber mills don't like B L cause it gets the 'shakes'. My interpretation... splits.
 
Black locust splits real easy, hence it was used for split rail fences(also because it was rot resistant), I have cut down alot of BL in the past, it escaped into a prarie, and it would split alot of the times, especially the times I did work with it during the winter.
 
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