Pulling a tree: Do you agree?

[MasterBlaster]

Today I worked for a guy that believed to pull a tree over with a rope you tied the rope to another tree and then used your bodyweight to pull the rope down.

I thought that was WACK. :what:

I untied the rope and used my arms to pull, with my foot against the tree, instead.

He thought I was wrong, and I think HE was wrong.

What say ye TreeHousers?

 

[SkwerI]

Using the deflection method (like your buddy) will give you about twice the initial pull. Plus it's a good safety in case a headwind kicks up and tries to take the tree the opposite direction.

I'll let Kenny explain the angle of the dangle.

 

[NickfromWI]

I think most people pull the way you do. However, you get MORE pulling power when you pull down on an anchored line. That's called sweating the line. If there is enough tension on the line when it is anchored, you can almost double your pulling power.

The trade off is that you can only pull as far as you can deflect the rope. Your way, you can just keep walking back, or in tight quarters you can hand-over-hand the rope. His way, if the rope is 6' above the ground, you can only pull down 6'...then you have to start going sideways.

love
nick

 

[No_Bivy]

vectoring the rope....it works. I usually just pull though.

 

[Blinky]

I normally use a tightline. Set the rope, face the tree, tighten the rope (doesn't take much on live trees), put in the backcut. If it doesn't go, I walk around and pull the rope. With dead trees I leave a beefy hinge and pull the tightline with a 5:1.

If you use the deflection method, you can theoretically keep the tree under tension a little bit longer because the rope doesn't go slack until you run out of room to pull it down.

Either way, I only use the rope to start the tree falling... and it's my aiming guide when I cut the face.

 

[Cobleskill]

I have done it both ways. I also have come around the anchor tree and through a loop in the rope to increase the pull.

 

[No_Bivy]

GRCS for me....for sure every time.

 

[NeTree]

Using the deflection method (like your buddy) will give you about twice the initial pull. Plus it's a good safety in case a headwind kicks up and tries to take the tree the opposite direction.

+1

 

[MasterBlaster]

I'm not talking about headwinds. I'm saying I'm stronger pulling with my arms (AND bodyweight) than grabbing the line and bouncing up and down on it.

 

[Paul B]

I would say logistically you cant pull up (or down) with more force than your body weight as you would lift yourself off the ground, can you pull more semi laterally than you weigh? Not you in particular MB, I am just trying to understand the physics of it.
With a line tied to one tree (the pulled one) and to another tree (the anchor) wouldnt you be sharing the pulling force between those two points thereby reducing the pulling effectiveness vs standing and putting your weight into it?
Using your body weight and legs braced against a tree you should be able to pull at least more than twice your bodyweight.

Kenny? R U out there?

 

[MasterBlaster]

I can pull a tank if I can secure my foot against something.

 

[SkwerI]

If you're holding the loose end of a rope and pulling on it, you can get what, about 200 lbs pull? If you're super strong and have something to brace against, maybe 250?

OK, now let's pull the rope tight and tie it off to an anchor. Now when you hang on it, you're putting 200 lbs pull on each end of the rope. That's almost 400 lbs total pull (you lose a little bit with the angle you're placing in the rope). And you're not working very hard to do it, either.

Like I said, Kenny can explain the angle of the dangle if you don't understand the math.

 

[MasterBlaster]

Maybe that works for a pencil neck, but like I said I can pull a tank.

 

[SkwerI]

You'd be surprised if you ever got access to a scale that could measure pulling force and actually got yourself some hard numbers. The math is against you on this one, Butch.

 

[Paul B]

Skwerl, my math says two anchors, 200 lbs = 100 pounds (roughly) per anchor point? I could be out to lunch on it but heck, how else am I gonna learn?

 

[NeTree]

Brian's formula is about correct, or enough to illustrate his point.

Been awhile since Engineering in college, but...

Picture a line through a pulley, then straighten the line. The force is still amplified.

Yeah, you're not going to move it much, but really... once it gets over center, it's going down like a $2 hooker anyways. You don't often three or four feet of pull; half a foot will do.

Or picture this:

Take a line tied to a tree, and hang a 100 pound weight in the middle. It'll take 200 pounds (give or take) to pull the line (almost) straight.

 

[okietreedude]

i use my mini-skid unless its a small tree. if its a BIG tree, ill put a truck on it.

small stuff gets the 'butch' method.

 

[SkwerI]

Butch, you play guitar. Maybe this comparison might help.

Try disconnecting one end of a guitar string and pulling on it. How hard do you have to pull in order to break the string? How much effort does it take? A lot, huh?

Now try grabbing the next guitar string that is still connected on both ends and tensioned. Grab it in the middle and pull out on it. How much effort do you need to put on it before it breaks? It's damn easy to break it when it's still connected at both ends. Dang, you must be putting an awful lot of force on that string.

 

[sotc]

if it needs that much pull ill hook up a block purchase

 

[MasterBlaster]

Butch, you play guitar. Maybe this comparison might help.

Try disconnecting one end of a guitar string and pulling on it. How hard do you have to pull in order to break the string? How much effort does it take? A lot, huh?

Now try grabbing the next guitar string that is still connected on both ends and tensioned. Grab it in the middle and pull out on it. How much effort do you need to put on it before it breaks? It's damn easy to break it when it's still connected at both ends. Dang, you must be putting an awful lot of force on that string.

My whole thing is I'm saying I'm stronger with my foot secured, throwing my bodyweight into it, and using my massive guns to pull. Doing it the other way only allows bodyweight to do the pulling.

Capish? :what:

 

[SkwerI]

So you can't pull sideways on a rope? Why not? It has absolutely nothing to do with the method of pull, it has everything to do with the mathematical laws and leverage.

I'm afraid you're the one who doesn't understand, Butch. But your massive guns will muscle you through and you'll do just fine.

 

[MasterBlaster]

The whole thing is my foot being secured. Without that, I can't pull nothing - like hanging on a rope.

 

[Stumper]

Butch. YOU can pull harder with your legs braced BUT Your guy was absolutely right. It is a matter of leverages. As anchors appoach 180 degrees to the load application forces aproach infinity.----Of course you don't keep your straight line-- a very small ammount of force will deflect the line. The first couple of inches of draw on a strung bow are relatively easy.... a tight cable still sags under its own weight. As a practical matter a tightly strung line will give you approximatey a 5/1 application of total force.......2.5 times the pull on one end.

 

[lumberjack]

For generating sheer pull, I'm with the other guy. I could beat MB in (short) tug-o-war with two fingers by deflecting an otherwise horizonal line.

As to actual practice, it depends on the situation, just like everything else. All else fails I use the GRCS/Mini.

 

[Underwor]

Here are a couple of deals I used to show how force is magnified by securing both ends. Our math guru says that they are right.

http://165.234.175.12/photos/Skills Images/compound%20tension_pulling tree.gif

http://165.234.175.12/photos/Skills Images/ tension calcs.xls