Top movement during topping

[pantheraba]

We've probably all seen the video where the climber plays rag doll when the top pops.

I just found this video, they titled it "Stem Wobble". It looks like a reasonable amount of movement to me. Could it have been made even "softer" or less? maybe by changing the type/size of face cut made? (you can't see what type he used, I am just raising the question).

Would a Humboldt type cut let the top slip off more than push back against the spar?

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[brendonv]

If you continue to cut through the hinge while its going over you will get less and less wobble. When the hinge is in tact it's wanting to push the tree the opposite way of the fall.

Thats what I've heard at least.

 

[MasterBlaster]

I always put a snipe in unless I want the top to jump out a bit. The stem wobble in the video was because he used a wedge. If he woulda just cut it off it woulda ploped over with minimum trunk movement. The thicker the hinge the greater the catapult effect.

 

[okietreedude]

arbormaster says to leaave some limbs on the bottom below the cut and it will help reduce the sway.

 

[MasterBlaster]

That's called "dampening" and it doesn't really reduce the sway so much as it absorbs the energy.

 

[Frans]

arbormaster says to leaave some limbs on the bottom below the cut and it will help reduce the sway.

Actually, the idea is to leave branches staggered up the entire length of the stem.
Not alot, just a few here and there evenly spaced and hopefully growing in different directions.
My experience MB, has shown me that it really does reduce the bounce effect (by reducing the 'push' of the top coming off).

 

[MasterBlaster]

I just can't see how that's possible. The limbs have no effect on the top. The limbs affect only the spar, dampining the shock thereby "reducing the bounce effect."

 

[Tom_Scheller]

The top only has so much energy to push the spar. The more limbs you leave, the more mass the spar has, the more energy it takes to set it in motion, and the less it will move.

TS

 

[MasterBlaster]

We'll agree to disagree.

 

[Tom_Scheller]

I was gitt'n error messages trying to post, hence the double.

TS

 

[MasterBlaster]

Not a problem, bro.

 

[RIVERRAT]

The top only has so much energy to push the spar. The more limbs you leave, the more mass the spar has, the more energy it takes to set it in motion, and the less it will move.

TS

I am not understanding this at all. Mass in motion equals energy. The more mass the more energy. After it gets moving any way.

What you describe would only make sense if the limbs left attached some how changed the direction of energy at the hinge.

I will try rap my mind around this for a bit

 

[wiley_p]

Butch you are right is saying that cutting up more wood the piece tips over with less sway on the pole. Having limbs left on the tree adds weight, and reduces any force imparted by the top pushing off. Adding a snipe helps, as you said unless you need some horizontal distance to clear a target. Go top a a central leader tree with most of the brush still on below you observe movement. Do the exact same procedure on a clean spar with a top, you will have more movement.

 

[stehansen]

I thought you were supposed to cut a wide face cut so that the face wouldn't close until after the trunk was done pushing on the top and was on it's way back. And have a small hinge.

 

[Tom_Scheller]

The limbs make the spar heavier. So it is harder to push.

Just think about trying to push a water barrel. Empty it's easy. Full it's hard. No difference with a tree limbs vs no limbs.

How you cut the top changes the energy that the top can exert on the spar, but the top only has x amount of potential energy to start with. By tinkering with the notch and hinge you can change how much of the spar's potential energy is converted into "spar wobble."

TS

 

[RIVERRAT]

OK,we are talking about leaving limbs "BELOW" the top.
Now this I can understand

 

[RIVERRAT]

Stehansen, that is correct

 

[arborworks1]

Less hinge wood has always seemed to reduce the catapult.

 

[brendonv]

What's a "snipe"?

 

[MasterBlaster]

<jsu>

 

[brendonv]

Not what I was thinking.

I was once told to make the cuts in the pic below, on a tree such as a hickory. They are very shallow on each side under the hinge, maybe 1 inch deep. I thought it was so the top broke off easier? Or was I just wasting time/doing something stupid?

 

[MasterBlaster]

Yep, that's what it looks like.

I have no idea what the cut you're talking about does.

 

[RIVERRAT]

No you weren't being stupid. They are called relief cuts. That is what I was explaining. With out relizing we where talking about a snipe cut.

 

[sotc]

brendan, your little cuts are to stop the hinge wood from peeling a strip of wood down to your flip line.
as far as the video goes it looked like the top stayed on a good long time and went very smooth. could have been just a long skinny pole

 

[lumberjack]

+1 To Willie's definition. They keep the bark left intact by the hinge from peeling down into your lanyard, called wing cuts typically.