Gord
ArboristSite Operative
To call a .doc file non-standard/closed format isn't what i'd call computer savvy... 
Directional pull line for felling
- Thread starter Ekka
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arboromega
ArboristSite Operative
nice job with this post everybody.
What is premium angle to pull the line from for best rotation on the hinge?
As we look at the static properties, angles and forces; how do they change at movement/ rotation? Does their previous loaded inertia have any consequence on the changed position (brief/sharp, rotational force?).
i think that for sure the maximum hinge tension strength is set at first folding, as an equal and opposite type of response; begins to fail. If tree will fall of it's own weight without stalling or sawing at that point; hinge is maximum strength; and acceleration of force minimum. So, that any force, even brief, sharp force; scheduled at first folding, increases the hinge strength in response.
i think the over the top lacing, cradles the load more; increases the number of loaded points on the pulling axis, giving more stable, focused bringing forward. Not necessarily more power there(that point), but better use of it i think; like less wobble in tire, more smooth, directed force.
The line at the bend is pushing down, the hitch is pulling up. There are tons pushing down, but nothing else pulling up; at rotation, angle shift of spar this unique event might give some measure of advantage, where none was before. On a rotation, that up pull (from hitch) compounding the down pushes on other end.
These are some of the more elusive points i've had to consider in watching this for years and thinking there is use for the bent line in rigging and felling. In rigging the weight of the load becomes the source of pull on the restricting line, bent around the load; to give similar, observable forces (i think). Especially on slow rotating stuff, you are muscling through on the hinge. In between fall and stall; extending first folding of hinge. Where, it won't fall on it's own, but line pull doesn't let it stall, i think the effect of the lacing over the top/ around the load; is most noticeable as a force of it's own.
But, it has driven me 'ier!
Some old drawings.
As we look at the static properties, angles and forces; how do they change at movement/ rotation? Does their previous loaded inertia have any consequence on the changed position (brief/sharp, rotational force?).
i think that for sure the maximum hinge tension strength is set at first folding, as an equal and opposite type of response; begins to fail. If tree will fall of it's own weight without stalling or sawing at that point; hinge is maximum strength; and acceleration of force minimum. So, that any force, even brief, sharp force; scheduled at first folding, increases the hinge strength in response.
i think the over the top lacing, cradles the load more; increases the number of loaded points on the pulling axis, giving more stable, focused bringing forward. Not necessarily more power there(that point), but better use of it i think; like less wobble in tire, more smooth, directed force.
The line at the bend is pushing down, the hitch is pulling up. There are tons pushing down, but nothing else pulling up; at rotation, angle shift of spar this unique event might give some measure of advantage, where none was before. On a rotation, that up pull (from hitch) compounding the down pushes on other end.
These are some of the more elusive points i've had to consider in watching this for years and thinking there is use for the bent line in rigging and felling. In rigging the weight of the load becomes the source of pull on the restricting line, bent around the load; to give similar, observable forces (i think). Especially on slow rotating stuff, you are muscling through on the hinge. In between fall and stall; extending first folding of hinge. Where, it won't fall on it's own, but line pull doesn't let it stall, i think the effect of the lacing over the top/ around the load; is most noticeable as a force of it's own.
But, it has driven me
'ier!Some old drawings.
P_woozel
ArboristSite Guru
How about proper size up of the tree/stick, try using wedges (iknow its new territory for many of you) Become comfortable with your falling ability or in some cases learn the fundamentals. Most of the time a pull line is used it isnt truly needed. This discussion proves that. Learn how to judge a trees lean. :blob5:
:blob5:
A line can pull over longer range, a wedge gives 'dead lift' that can't be taken back by tree, like risk of tree responding back to rope pull. A wedge loses it's leverage the deeper you make the face i think; but with a line you can go deeper under CG, and still have leveraged help. Huge, Huge trees might take too much line, too high a shot, when wedge could simply tilt the balance with lots less gear! Different strategies.
i think we should give force to target direction (in good wood); to give more strength to hinge, than is forced by tree's own weight and angle; for better results. Raising the hinge strength to higher value, to prep it for the increased leverage on hinge with every degree of fall. Interuptions in face use whatever of that force; to load disconnected compression; instead of forcing more connected tension in hinge. The hinge tension doesn't carry as much load, as a face closes; so forcing more pressure here doesn't give more steering, control by saw or connected support. Taking the face, is meant to remove this resistance, and place all control at the rear tensioned hinge fibers, reachable by saw to control, by disconecting fibers. Forcing compression, puts power were the saw can't reach it, and also is already disconnected anyway.
The rope fiber too, is connected control, for more of the ride on hinge arc, the wedge only seconds of flexing on hinge. More insurance, over the distance with rope, and unubstructed face. Both allowing connected control over the longest distance.
i think we should give force to target direction (in good wood); to give more strength to hinge, than is forced by tree's own weight and angle; for better results. Raising the hinge strength to higher value, to prep it for the increased leverage on hinge with every degree of fall. Interuptions in face use whatever of that force; to load disconnected compression; instead of forcing more connected tension in hinge. The hinge tension doesn't carry as much load, as a face closes; so forcing more pressure here doesn't give more steering, control by saw or connected support. Taking the face, is meant to remove this resistance, and place all control at the rear tensioned hinge fibers, reachable by saw to control, by disconecting fibers. Forcing compression, puts power were the saw can't reach it, and also is already disconnected anyway.
The rope fiber too, is connected control, for more of the ride on hinge arc, the wedge only seconds of flexing on hinge. More insurance, over the distance with rope, and unubstructed face. Both allowing connected control over the longest distance.
P_woozel
ArboristSite Guru
Maybe I should say a pull line isnt always used properly, I see guys set a line when wedgeing will suffice, or see guys set a line as a matter of course in a tree that has obvious favor to the lay, then I watch the same guys not set a line when taking a 30' conifer top that has a difficult read, when they are a 100' up dropping into a 50' long by 20' dz. I am fanatic about pull lines, when they are needed. I wish I could do in town what I do in the woods.
i think wedge push and/or line pull can be used on a tree that favours a lean to target, to force a stronger hinge for softer landing. Once again in good wood, using the line not to direct the tree, but force the hinge stronger , then let the stronger hinge steer and lower the tree.
fpyontek
ArboristSite Operative
There are only two component vectors of force from a pull line which act upon the tree, a horizontal component (toward the direction of the applied force) and a vertical component (down the tree).
For an explanation go to: http://www.physicsclassroom.com/Class/vectors/U3L3b.html
To answer the original question from Ekka, the advantage of either method may depend upon the situation. A rope can suffer up to a 50% loss of breaking strength after tying a knot. See http://www.treevolution.co.uk/documents/Ropes.htm (scroll down to the paragraph under the heading "ROPE APPLICATION (Safe working loads and knot strength)". The advantage to method (B),(tying the knot near the base of the tree) is that the friction against the rope through the crotch and the additional friction of the rope around the larger diameter of the lower trunk is applied along a larger area and reduces the stress to the rope at the bend in the knot.
A disadvantage to method (B) could be that there may be no good crotch to go through. The rope could be lying over a limb, such as in a spruce tree, where the limb could break with relatively little force applied to the rope. In that case, method (A) would be better.
Getting back to the vertical component of the applied force (down the tree). At a 45 degree angle the horizontal and vertical components are equal (but tree guys who stand with the rope at a 45 degree angle while pulling a tree over won't last very long). As the vector of the pulling force moves further away from the tree (the guy pulling the rope moves back) the vertical component of of that force reduces quickly.
Assume you have a 100 ft tree and you place the rope 3/4 up or 75 ft. In order not to be hit by the tree you would need to stand at least 100 ft away. Say you stand back 25 ft additional for safety or 125 ft from the base of the tree. The angle of the rope is then arctan(75/125) or approximately 30 degrees. At that angle if two 250 pound guys pull on the rope (assume 500# force for simplicity), the horizontal component of the applied force is: cos(30)*500 = 433 pounds of force applied to the point 75 feet up the tree. Thats 75*433 = 32,475 ft lbs of torque applied to the base. The vertical component of the applied force is: sin(30)*500 = 250 pounds pushing the tree into the ground (a good size climber bear-hugging the tree)
I'm not trying to say dropping a tree is simple, it is DEFINITELY NOT! As you all know there are many factors to consider. I'm sure that there are homeowners or "nubies" to the tree business that read these posts. I would just like to point out to those readers that there is no one way to drop every tree. A wedge will not always work! If the tree is hollow you may not get to the back cut before the tree falls backward.
For an explanation go to: http://www.physicsclassroom.com/Class/vectors/U3L3b.html
To answer the original question from Ekka, the advantage of either method may depend upon the situation. A rope can suffer up to a 50% loss of breaking strength after tying a knot. See http://www.treevolution.co.uk/documents/Ropes.htm (scroll down to the paragraph under the heading "ROPE APPLICATION (Safe working loads and knot strength)". The advantage to method (B),(tying the knot near the base of the tree) is that the friction against the rope through the crotch and the additional friction of the rope around the larger diameter of the lower trunk is applied along a larger area and reduces the stress to the rope at the bend in the knot.
A disadvantage to method (B) could be that there may be no good crotch to go through. The rope could be lying over a limb, such as in a spruce tree, where the limb could break with relatively little force applied to the rope. In that case, method (A) would be better.
Getting back to the vertical component of the applied force (down the tree). At a 45 degree angle the horizontal and vertical components are equal (but tree guys who stand with the rope at a 45 degree angle while pulling a tree over won't last very long). As the vector of the pulling force moves further away from the tree (the guy pulling the rope moves back) the vertical component of of that force reduces quickly.
Assume you have a 100 ft tree and you place the rope 3/4 up or 75 ft. In order not to be hit by the tree you would need to stand at least 100 ft away. Say you stand back 25 ft additional for safety or 125 ft from the base of the tree. The angle of the rope is then arctan(75/125) or approximately 30 degrees. At that angle if two 250 pound guys pull on the rope (assume 500# force for simplicity), the horizontal component of the applied force is: cos(30)*500 = 433 pounds of force applied to the point 75 feet up the tree. Thats 75*433 = 32,475 ft lbs of torque applied to the base. The vertical component of the applied force is: sin(30)*500 = 250 pounds pushing the tree into the ground (a good size climber bear-hugging the tree)
I'm not trying to say dropping a tree is simple, it is DEFINITELY NOT! As you all know there are many factors to consider. I'm sure that there are homeowners or "nubies" to the tree business that read these posts. I would just like to point out to those readers that there is no one way to drop every tree. A wedge will not always work! If the tree is hollow you may not get to the back cut before the tree falls backward.
fpyontek ,
you explained in detail what I meant in my previous post. Best answer so far to my opinion. In order not to offend animal protectors, it would be wise to inform the climber bear to get out the tree before you start pulling the rope ....
you explained in detail what I meant in my previous post. Best answer so far to my opinion. In order not to offend animal protectors, it would be wise to inform the climber bear to get out the tree before you start pulling the rope ....
Yeah, that <i>was</i> good. I see it as basically a well-fleshed-out and proviso'd version of what I've been saying all along, except for the omission of the extra 500# (nominal) which would be added to the 250# downward force at the crotch/limb with the laced setup (for a plumb bole).
Addressing the knot strength: even if the bowline had a 50% reduction rating, the setup would tend toward full line strength again since the bowline itself would be essentially carrying only ½ the direct load, being wrapped around the tree/limb back onto the line. Right?
Glen
Addressing the knot strength: even if the bowline had a 50% reduction rating, the setup would tend toward full line strength again since the bowline itself would be essentially carrying only ½ the direct load, being wrapped around the tree/limb back onto the line. Right?
Glen
Nice Job Fpyontek (such an easy name to remember...);
The Mayhem Puzzle proved there would also be a force component pulling up from the hitch.
Also, more compression isn't always a bad thing; i use it as in Hinge Pocket Pressure Rig. Which is a rig with the bent line mechanics on a load, that is self tightening (to create the line pull) with more leverage the farther from hinge the bend in line is. Also, this rig adds the angle of the line purposefully compressing into the hinge, to hang on with less fiber in hinge, for hinge holding on, but turning easier with less fiber resistance.
i'm not sure the downward compression would be signifigant on a large tree, whose total weight was also pushing down. The downward compreesion into the stump, would depend on the angle of the spar i think. The hitch pulling up force would be a unique event though; i think. The static numbers and their inertias would alter at movement.
The Mayhem Puzzle proved there would also be a force component pulling up from the hitch.
Also, more compression isn't always a bad thing; i use it as in Hinge Pocket Pressure Rig. Which is a rig with the bent line mechanics on a load, that is self tightening (to create the line pull) with more leverage the farther from hinge the bend in line is. Also, this rig adds the angle of the line purposefully compressing into the hinge, to hang on with less fiber in hinge, for hinge holding on, but turning easier with less fiber resistance.
i'm not sure the downward compression would be signifigant on a large tree, whose total weight was also pushing down. The downward compreesion into the stump, would depend on the angle of the spar i think. The hitch pulling up force would be a unique event though; i think. The static numbers and their inertias would alter at movement.
Ken, I'm sure I'm "hearing" you say that the laced line with it's added downward pressure at its upper end would add to the downward pressure on the hinge/face, but I contend those control elements would not see one iota of it. It's entirely dispersed above them.
Sorry if that's not what you're saying; it can be somewhat difficult at times to be entirely sure. <tt>:</tt>)
Glen
Sorry if that's not what you're saying; it can be somewhat difficult at times to be entirely sure. <tt>:</tt>)
Glen
i was saying that more compression isn't necessarily bad. The downward force exists but is several hundered pounds in the midst of 5 tons (whatever); and also does have a countering pull up at the hitch (that is also unique in play of forces here).
i still think, there is something to the continued inertia of those pulls, as the spar shifts position. This makes the inertia of the pulls, not inline with the spar anymore, so therefore are leveraged; also acting in concert to spin. This i think could happen, briefly, sharply at first folding; which is the window of time to force the hinge more, to have more hinge strength maximized i think.
You have to consider torqued pulls on the spar (side to side) when choosing between the 2 methods.
i still think in a simple analysis, line to the same point; you can choose between the line pull or the line pull + bend in line wanting to come out; in choosing between the 2 methods. The force input is more arched on an arched action in the over the top lacing. i've used it felling at the standard angles. Also, rigging to side, pulling up, rigging thru highly leveraged horizontal plane, sometimes twisting hinge fibers sideways with it's power etc. for years. Of which i have been writing about different points of, starting at ISA board some ~7 years ago.
i still think, there is something to the continued inertia of those pulls, as the spar shifts position. This makes the inertia of the pulls, not inline with the spar anymore, so therefore are leveraged; also acting in concert to spin. This i think could happen, briefly, sharply at first folding; which is the window of time to force the hinge more, to have more hinge strength maximized i think.
You have to consider torqued pulls on the spar (side to side) when choosing between the 2 methods.
i still think in a simple analysis, line to the same point; you can choose between the line pull or the line pull + bend in line wanting to come out; in choosing between the 2 methods. The force input is more arched on an arched action in the over the top lacing. i've used it felling at the standard angles. Also, rigging to side, pulling up, rigging thru highly leveraged horizontal plane, sometimes twisting hinge fibers sideways with it's power etc. for years. Of which i have been writing about different points of, starting at ISA board some ~7 years ago.
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P_woozel
ArboristSite Guru
treespyder, all the crap you say gives me a headache, you are obviously intelligent but I would like to see you work in the feild cause I wonder if you really can show this crap you yak about. Have you ever said yes or no to a question? Push/pull compress that. 
