I'm trying to determine line pull on a back leaning tree being felled against the lay.
I have the weight of the tree, the distance it leans back from center and the angle and height of the rope where it is attached to the tree.
What I want to determine is, how much force the rope must endure pulling the tree vertical?
The tree is cut with a hinge.
Anyone have an equation for this?
(https://forestryforum.com/images/04_01_03/math%20question.JPG)
Without calculating the resistance of the hinge. etc etc etc...
F=force (Ftlbs)
W=weight of tree
theta=acute angle of the tree
Y=height rope is tied to the tree
H=height of the tree
F=W*sin(theta)*(Y/H)
as is not proved!
How about overall length of tree, swish area and circumference area in case of trouble (wedge prematurely breaks loose) ;)
From other threads I respect your thouroughness and regard for safety--just thought I would poke a little fun :D :D Dan
Thanks FBC, I'll have to try and get someone to check that out, I've been out of school a long time and I think this is one of those exercises that I said I would never have a use for. :-/
Dan,
Quotewedge prematurely breaks loose
That wouldn't happen, I don't use wooden wedges. :D
Did quite a few similar calculations in my prior life for river crossings with telephone cable or river crossing wire. Some as long as half mile. Can't remember the formula I used but do know it is a lot easier to plug in the lead or length of your rope rather than the angle. You would also need to know the strength of your stem so you won't break it.
In reality I would go with your judgement and if in doubt use a steel cable that you think is the right size.
Larry;
The general rule is you use the best bull rope you can buy for big trees and try and see if you can lift them before you commit.
I don't often get into any real big stuff and when I do it usually gets pieced down.
Cable is pretty much out of the question these days with the new synthetic bull ropes that are available.
Here's an example ... Samson (http://www.samsonrope.com/home/industrial/rigging-12strand-amsteel-blue.cfm?ProdNum=154)
For monsters you might use a large steel cable with large winching forces to back it up but from what I understand you need rigging in the tree just to pull up the rigging.
We are talking 1 1/2"steel cable.
Most guys will tell you to use gut instinct but it wouldn't hurt to do a rough estimate just to confirm your thoughts.
Pulling from center of balance might not be a big deal but large back leaners could test your equipment.
Kevin mabie you could post the numbers and someone could figure it out. That formula is greek to me, but I would like to see the results also.
The tree is 90' tall
It weighs 10,000lbs.
It leans back 10' from center at the top
The rope is secured at 60'
The rope is 150' long and set at a 50o angle
The tree is cut and wedged and just needs to be pulled over on the hinge.
What is the force required to pull the tree to center of balance?
Kevin,
I've been out of school a looong time myself. Home schooling my children so I've had to, :P :P :P, to refresh myself on trig calculus and physics, plus my oldest is in college and has always liked to ask abstract questions. ;)
The function can be put into a spreadsheet as is. As I'm sure you know, it's not very complete i.e. wood density, tree taper, crown diameter/height/taper and weight, rope angle, hinge volume etc. etc. I don't fell trees so there may be other variables I'm not considering. ?
I'll work it out a little more tonight and post back.
Hey Kevin, would the experts of GOL need to pull it? Maybe your one of those guys. ;) Why the need to pull...it doesn't seem like your style ;) Leaving a tree notched for days while you figure forces doesn't seem consistant either. :o Please don't take this as an attack, have read alot of your inputs and threads and have alot of respect for you. :) Just curious. DAN
Hi Kevin,
Can you estimate where the centre of gravity would be on the tree? I think knowing the centre of gravity is important because then you can use force diagrams.
Guessing that the centre of gravity is at 45' up the tree I calculated 1220 ft\lbs of force is needed on your 150' line.
Here's a pic of how I got this. I'm not 100% sure this is the right way to do it but the numbers make sense. I wouldn't park your truck behind the tree if your using 1220 lb rated line though! :)
(https://forestryforum.com/images/04_01_03/treeforce.jpg)
Hope this helps,
Ian
Ian
That looks pretty good. Do the line forces drop to zero when the tree is standing straight up? Didn't try to work out your numbers with the previous formulas. I suspect the forces on the line go up pretty fast if in fact the tree is 11' off center at the top, rather than 10'.
OOPS! I hope kevin hasn't tried to cut that tree yet! :-[ ;)
Beenthere prompted me to check my thinking again...
I tried running the numbers with the rope at 20 feet and the force doesn't get high enough...
I'll get back to you guys when I've got it...
Ian
Well I screwed up too, inverterted H/Y should have been,
F=W*sin(theta)*(H/Y)
Kevin,
I know that TCIA and ISA in recent years have been promoting bull rope usage. And due to a lack of experience in application down play wire rope. Further make claims that 1 1/2' wire rope is needed. This simply put is not true.
I operated a tree business for 20+ years and use used 150' of 3/8" wire rope. Greatly benefited me, especialy for situations like your above proposed diagram. Climbing with this cable is not that difficult. I would not trust many of the bull ropes which were much heavier to pack into the tree. I have had the misfotune of seeing bull ropes fail. But not once in 20 + years ever had my wire rope fail.
The cost of the wire rope would have been excessive, except that I found a tow truck supplier that had them made up with hook ends for 1/3 the cost of bulk wire.
I have only been doing this a short time, so take the advice with $0.01 because I do not have enough experience to even think about doing the tree you are.
I use a winch (or my truck) most of the time to pull trees over once the hinge is cut. I do it mostly so I am not near the tree once it starts to head over.
A 2" hinge in oak 36" wide will easily stall a 2,000 pound winch on a straight standing tree. Think of it as trying to break (18) 2x4s lined up straight across.
To pull this tree over, you have to break the hinge/wood fibers (since the grain follows the tree) and pull that tree over to you, at this point there is no real holding fiber and the winch is doing all the work.
imo, If your truck is not heavy enough and the wire strong enough the tree will fall the way you do not want to.
I would only try this with a winch and line rated 1.0-1.5 the weight of the tree. Things to consider, a winch this big will heat up fast and drain the batteries fast. You will only get once shot at pulling this over unless it is a hydraulic winch because most electric winches can only pull about 1-2 min. max at their top load rating.
If this tree starts going the other way, you should have a second line on something heavy and immoveable to give you (or the winch) time to recover. Ideally, I would pull a foot at a time on the winch, then have the second vehicle tension its line.
Things to consider:
Fiber rope loses something like 30% of its strength at the knot or loop in a winch situation.
I have tested (nylon) rope to see when and where it breaks. From what I have done, it stretches a lot, then breaks at the knot or loop closest to the load.
Rope (and somewhat cable) loses its strength rating the longer it is and the greater the angle. A flat pull puts less stress on the rope than a 45 degree pull. Think of it like a log, compression and tension.
Most winches and their mounts are calculated at a straight pull. The greater the angle (especially the mount) the weaker they are.
A winch on its first layer of wire is probably capable of snapping the wire it came with from the OEM.
If you do not anchor the truck to another tree, it better weigh at least as much as the tree because once you have the winch going, it will lift up the pulling end.
Using my little 2k/6k winch I have buried my tires in the ground (I have four wheel hydraulic brake locks) and compressed my suspension a good three-four inches before the tree gave way.
I think a 26K truck with a pintle hook would be the ideal dead weight vehicle to anchor the second line because empty it weighes probably 12k.
I would make sure where I put that winch line (I use 3/8 chain - you should probably use a 1/2 inch logging chain) the tree would not crack in 1/2 at the stress and have the top pop over.
My experience has been rope and cable gets buried in a tree and cuts through it. A chain usually stays right on the top and does not go deeper than one inch into the wood and removes easily.
I've been trying to make a calc for this since Jeff asked me to take a look at it yesterday. The math was beyond me so I started E-mailing our resident physics professor Mitch 8).
He sent me another formula to use and I tried till almost midnight last night, I was worried. I E'd Mitch again last night and asked him to work the problem, he did that and sent me more info for working on the calc, it was here when I just walked in.
Here's the quick answer, if the center of gravity is halfway up the tree the force required is 1090 lbs, worst case is the CG is 3/4 way up and it becomes 1640 lbs. This is assuming the tree is cut through and freely pivoting....which it isn't, so account for that.
I'll work on it more tonight and put up what i've got after...food ;D
Thanks Mitch 8) 8) 8). (we need a hat's off smiley)
Dont forget wind.
If it were me,I like the 1/2" cable idea, when I worked for the tree service we only used ropes, weve done a fiew similar to that with 1" bull rope, hooked to a tree truck or backhoe and the most important thing, goooood insurance.
Since Ive been working for the state park service Ive been doing things a little differently, now I would use the cable.
Kevin whats around the tree, that you have to pull it over backwards??
Wes
Wind? Oh great, another abstract variable!
CG hmm. OK! I'd just overkill to be on the safe side but I do enjoy the math.
Stephen;
The large cable was used and might still be out west on the large trees.
The information I passed on is a direct quote from Gerald Beranek who wrote the Fundamentals Of General Tree Work.
Gerald worked the big sticks on the West Coast for many years.
No disrespect meant here but I don't know of a single arborist who uses wire rope for pulling trees today with the high quality ropes that are available.
The tree in question is being pulled over by another qualified person in the U.S and is situated near power lines .
The estimate that he and another arborist came up with (separately) is in the 1200# range.
Don is attempting to make a calculator that takes some of the guess work out of it, the final responsibility is in the hands of the guy doing the tree work.
Because of all the variables involved it can only be used as a guide.
Dan:
QuoteLeaving a tree notched for days while you figure forces doesn't seem consistant either.
Who said that?
:D
Mitch fixed my attempts and quickly put up a working version, take a looky here.
http://shagbarkfarms.com/LmbCalc/linepullclc_DonPF.html
Also go to his website and click on the Log/Lmb Calculators at the top of the page here:
http://shagbarkfarms.com
He has a nice site I'm sure many of you will enjoy looking around in.
That looks really good Don.
I'll let you know what the critics think. ;D
Hells bells and cockle shells,
Fall the DanG thing sideways :D
Tie it like you have shown in the pictures, anchoring to something imovable-------you don't need a winch.
Make your notch 90 degrees from the lean and hold a corner when you backcut.
Even so, wouldn't hurt to follow Wes's advice and have goooooood insurance ;D
Yo Bro;
Thanks for the advice.
Even though a force of 1200 pounds is a decent pull a 5:1ma can reduce it to a little over 200 pounds so it looks like you might be right again, you might not need a winch.
Well now, Mitch found my problem from last night, in javascript angles need to be converted from degrees to radians. 8) 8)
https://forestryforum.com/members/donp/linepullclc.htm
He figured the inputs to use as this,
Center of gravity 45'
weight 10000 pounds
tree angle 83.6 degrees
height of rope 60'
angle of tree to rope 50 degrees
I've just been having fun substituting 90.0001 degrees for the tree angle. Shoot I can hold that puppy up no problem :D
Don't forget the hinge wood Kevin ;).
Don;
How do you determine where center of gravity is on a tree?
Is it half the tree length?
QuoteThe tree is cut with a hinge.
Come on Kev, your not going to make me get into the definition of "IS". :D :D :D
Oh sorry;
I thought you were on another reply.
What I meant there is the tree is cut with a hinge meaning it's ready to be pulled so how much force will it take?
Don P,
Looks good. That was fun.
My heads going to spin for a while after reading this thread :o Never did like math especially algebra. That 's why I've got a history major ;D I'd use a big steel cable and wooden wedges and not worry about it ;) :D :D :D ;D ;D
That was fun, in a tortured hair pulling kinda way :D. I tried a calc based on your formula first FBC, but discarded it when my results weren't looking good. I did try inverting the h/y, as well as sin/cos and about a dozen other things. It was the degree/ radian thing tho :-/.
Since your homeschooling...pull up my version of the calc. right click and pull up the dialog box, and left click "view source" when the dialog box pops up. The calc program will appear. The javascript is in the top portion, I tried to make it easy to read. You guys should be able to tinker and play around with math formulas.
I graduated HS by .25 points, math stumped me, Algebra /Trig might have as well been chinese, I took it 3 times, truth is I think Miz Crook just gave me the quarter point so she wouldn,t have to look at me again...talk about slow children :D.
Center of gravity of the tree is where you could pick it up balanced. You'll have to hook the tree to a crane and slide the choker around till it balances, then measure from the butt up. ;D
Seriously, it should be about halfway up, but look out for a heavy crown, better to err high. Run the problem a few times moving only the CG around and you'll get a feel for how it affects the pull.
I play around with the variables in the calcs till I can visualize whats going on, that's their beauty to me. It does the math fast so you can model a problem several ways real quick, and get a feel for whats going on. Move the ropes, tip the tree, resize a beam, whatever...you can start to "see" whats happening.
...I just made a little flash. The thunder all belongs to Mitch ;).
I will beclear off base, I am sure. Number one, I like Bro. Nobles suggestion, if there is nothing in the way. It sounds as though a snatch block setup would be in order, even if you had to use a large vehicle.
But the thought I had, that would work very well, would be a crane. Some out here have used the cost of a crane in their bid and gotten the job. The cranes run somewhere around $700 to $800 an hour, minimum of an hour. I have used a small crane on a few jobs and it has wokred very well. You just need to be able to get the boom to the site of the tree. I have seen where the whole tree has been lifted over a house from a back yard.
Thats how you would take down a capital Christmas Tree. :)
http://www.mfra.org/bigtree.shtml
QuoteStephen;
The large cable was used and might still be out west on the large trees.
Gerald worked the big sticks on the West Coast for many years.
No disrespect meant here but I don't know of a single arborist who uses wire rope for pulling trees today with the high quality ropes that are available.
.......the final responsibility is in the hands of the guy doing the tree work.
Kevin,
As you mentioned Jerry Beranek worked a lot of logging on the bigger wood which required use of 11/2" wire rope.
I also logged using the heavier wire in the 70's and 80's. You don't pack 11/2" wire rope. 3/8" wire rope is a different story, I kept my spooled on an old chevy wheel or coiled and tied with 9mm rope..
Since 'tree wrecking' is mostly performed due to targets in or near the fall or lay, ropes provide ease of use to perform the task in piecing down trees.
However, your scenario was dealing with 'falling' a leaning tree. This is where I always applied my logging skills and knowledge to using 3/8" wire rope with a working load of 15k compared to a bull ropes 1200 -1300 lb work load.
Use of wire rope is not always applicable thus the tree must be wrecked using ropes. Both methods kept me competitive and performed the job safely and with ease.
Many times I was able to 'wreck' trees taking them down in two to three cuts using the wire rope, opposed to numerous cuts using ropes would have required.
BTW, never bothered me that many other arborists companys, did not make use of or have the ability to perform the same..........as it was part of my competitive edge. A few eventually found out and caught on tho.
Wire rope usage is simply another tool with greater working load capacity. When falling this provided me an additional tool especially in circumstances where the increase to the ropes working load was being jeopardized.
Kevin, I have enjoyed this thread from your question. :)
BTW, Jerry's old pic of spurring up a Euc is on Bailey's 2004 catalog. How many young arborists do you suppose are going to take him to 'task' for wearing those spurs?
It is neat to see that Physics and practical experience both have a place on the Forestry Forum.
I confess that when I went to cut a huge white ash ~ 36 inches at the base and with 3 huge trunks growing out with one over my cow barn leaning at a severe angle I did not sum torques nor use a computer. I sawed it nearly off with about a 2-3" hinge and with a 120' x 3/4" steel cable about half way up the tree started pulling with a 350JD track loader (~14,000 lbs). Would not budge it. Had to put another cable higher up the tree and hook the old 730JD (~8,000 lbs) to finally tilt it back away from the cow barn!
Mitch
Thanks for putting that applet together Don, I was spending way too much time trying to figure it out!
Ian
I want to sincerely thank everyone involved in putting that calculator together.
It will surely serve to add an element of safety in estimating the force that is incurred when felling large trees.
I'm getting some positive feedback on it from others who are more familiar with these forces than me.
Thanks for putting in the time and the effort.
Kevin.
Here's another handy site for rigging calculations.
http://catalog.thecrosbygroup.com/body_calculators.htm
Stephen;
I have no doubt what so ever that you are very familiar with wire rope and know what you're doing.
I don't have any personal experience with it for the task we've been discussing.
Rope works well for me but you have to take good care of it.
On another note I was up the north highway today at a tower site, it was so cold I thought my teeth were going to pop.
On the way up I spotted a black spruce that looks like it was blown over on the root ball.
This tree is towering over the phone cable and it will be like working off a springboard, should be fun.
I hope it doesn't stand up when I take the top off it! ;D
OH MOTHER!!!!! :o ???
a?..look at tree
b/ guess how big and where it MIGHT go
c/ cut notch accordingly
d/ make back cut
e/cross fingers
f/ grin and say " i ment to do that" iffin it falls where ya want
g/ if it DOESNT fall where ya want and starts goin ascue..
h/ run like the dickens screamin TIMBER!!!!!!!!!!!!!!!!!!!
I have added the line pull calc to the drop down list to the left. Way ta go everybody!
QuoteRope works well for me but you have to take good care of it.
On another note I was up the north highway today at a tower site, it was so cold I thought my teeth were going to pop.
On the way up I spotted a black spruce that looks like it was blown over on the root ball.
This tree is towering over the phone cable and it will be like working off a springboard, should be fun.
I hope it doesn't stand up when I take the top off it! ;D
Kevin,
Know that feeling of coldness, takes the fun out of the work. Can also make thinking clearly difficult. Not a good combination when dealing with hazardous trees.
Black Spruce - aw challenges and more fun...............I have had them stand up before while reducing. Managed to stay on for the ride!!!!!! Kinda of reminded me of topping at 175'+ also big rides.
However, have known of a few to set up and break remaining roots on leeward side, then shift and come back down. Thus the need to always expect the unexpected.
Be certain to do a full root inspection before climbing. Is the soil moist six or more inches below surface (due to cold would figure it to be hard)? If possible excavate scaffold roots on leeward side and inspect for breakage. Also note of any root rot on exposed roots.
I know you probably are aware of these issues - just want to remind you to be careful as dealing with windthrown or root rot failed trees often requires additional prepatory structural measures be taken for climber safety.
QuoteHere's another handy site for rigging calculations.
http://catalog.thecrosbygroup.com/body_calculators.htm
Thanks for that, Kevin! My husband recently took a crane course for his work and has started being crane operator for some of the jobs. I am going to show this to him when I get a chance.
One of the reference books that I just had to have when I saw it years ago is that little Thomas J. Glover's 'Pocket reference'. My kids *and* husband *and* in-laws looked at me funny when I got it- but they keep coming around to ask me stuff- the stepson got a set of carabiniers for Christmas and they were rated in Newtons. So first he wanted to know what NT stood for and then he wanted to know what the conversion was to pounds. I surprised myself when I remembered the term 'newtons (it's been a while..)- but the little book helped him right out. lw
um fellers??....i was only kiddin :-/
I have not read all the posts hear but I KNOW how I would go about doing it around power lines. For a 10,000 lb tree I would use 2 separately rigged 5,000lb lines or bigger to it at 45degrees to each other and lay the tree between them. I would also tie a figure 8 of 3/8's chain around the hinge cut so there is NO way it can go anyplace but the place I want it if the hinge cut blows out. I have a way of cutting a upside down hinge that the winch is pulling closed not open by cutting the backcut well below the V-notch, not above it. I have done this stuff a lot back in my towing and recovery days and the word of the day for this stuff that "oops" is not an option is if you think you need 100 pounds of force you better use 400 pounds or more. You need enough force to control the live weight of the load to be sure to control it and not have it get away so 10K should be the number on a 10K tree. You also got to think about what your deadman will hold in just the same way, 4 to 1 safety margin or better is the trade rule of thumb for overhead work like this. I can tell you from experience it is no fun to get something moving then watch your deadman go flying and your friends running for there life! ::) Trees often make poor deadmen. ;)
Andy
Andy;
These are my thoughts on this one.
The industry standard for wll (working load limit) is 5:1.
Arborists generally use 10:1.
I would never use steel around power lines.
I would make the back cut (adding wedges) a little higher on the apex behind a good open face notch, a higher back cut than normal on a back leaner in order to draw some pulling fiber which will serve to strengthen the hinge and keep the tree on the stump.
I would tie high on good wood, rig back to 90o to a block on another sound tree that has a guy back to the base of another tree.
Using a 5:1ma (now pulling about 300lbs.) through a rope brake and an appropriate bull rope like amsteel this tree should be about as difficult as a walk in the park.
Something like this ...
(https://forestryforum.com/images/04_01_03/sample.JPG)
Kevin,
I like the Physics of your previous post. The torque would be maximized if the red horizontal rope were at 90 degrees to the falling tree. By pulling from another tree you do not have to worry about "lifting" a truck or tractor rear end and thus reducing the pulling force. For example in your first post if the angle between the rope and the ground is 40 degrees, then the lifting force on a vehicle would be 64% of the tension in the cable/rope. Of course the longer the cable the smaller the angle with the ground and the lower the lifting force.
Kevin, if you are near power lines you are absolutely right in using ropes over wire.
One concern I have however with your recent pic and comments is the use of a 'higher back cut'. The set up is good, but with a higher back cut you would need consistent forward pull.
Stopping, or resetting pull (before you reach center of gravity) may cause the spliting out of holding wood and the tree will swing to the side.
Andy, I would not use a lower back cut in the above scenario. Unless the lean tree would be limb locked with adjacent trees.
I think Kevin has got this one on the ground !
I would pretention the line to hold the tree, make the back cut always keeping slight tension on the line, add wedges, continue with cut and slight tension and the kerf should open up as I near the hinge.
I would always be in control with constant tension but only enough to pull the tree and being careful not to over pull and cause unecessary stress.
The hinge will do the rest.
The reason for the higher hinge is to eliminate the hinge from letting go before center of balance is reached.
More hinge = more force but better control.
With a short hinge there's a good chance it will break before the tree is vertical.
mitch,
The calculator can find the numbers you need quickly.
It's a real asset in helping to keep everything safe.
I'm sure many will benefit from it and a life or two might be saved in the process.
Thank you.
Kevin,
1- What if it snaps the hing in your cut and the but falls free from the stump to the ground and you get a huge shock on your rigging? Will it hold a shock load from a 10,000 pound tree? 300lb X10 = 3000 pound line is is what you are saying? I am saying a 10K tree can make a 10K shock load on your line in 6 inches or less of free movement and a 3K line is way WAY under what I would use!
2- What if it twists the hing left or right and comes at you like a medieval log trap what do you do? I don't ever want to count on the cut 100% when I got to have the thing land on the "X" the first time. I want a first plan and a backup so if plan "A" falls apart I have plan "B" and even "C" if it's gonna land on a power line! I have had that deer in the headlights look on my face a time or two and it is no fun. ::)
I have no problem working with steel near powerlines I just keep them away by seeing that it's not gonna come in contact with it, none of it, no way no how, linemen use it every day. What I am saying is I have been bit in the but by under estimating line loads and trusting that things have no rot or week spots. ;) It's best to over kill the over kill then use a times 4 margin on top of that than to fix a powerline if I lived long enough. If I have a 10K tree I will have 10K worth of line on it every time or go home because it can make a 10K pull on you in a hart beat, this lesson was learned in the school of permanent marks to my body! ;) I agree with all the math hear I just don't see the potential for huge shock loads addressed. 9 times out of 10 your rig works 100% like you think but what about that 10th time? I'm a what if guy now days not the what the heck guy I was when younger. Also I don't give a rip about saving this log till it's down, if I got to turn it to splinters to keep it off things so be it, it's firewood if need be.
This is what I was saying. It cant go noplace but between the deadmen! ;)
(https://forestryforum.com/images/04_01_03/cut1_a.jpg)
I like the low cut as I have had them blow out like the pic on the left under winch load pulling it back upright. But with a low cut and a figure 8 like that it cant go far. I may also put a winch on the center of the 8 to keep it sucked up as it comes up.
(https://forestryforum.com/images/04_01_03/cut2_a2.jpg)
(https://forestryforum.com/images/04_01_03/Tree%20Lean.JPG)
Please note that weight of canopy is not directly over stump. Thus when pulling a lean tree to center of stump or desired center of gravity, the weight of canopy equals less than 1/2 of the weight of tree.
A 2000 lb. vehicle can be pushed by a 200 lb. man, obviously not very fast but still possible. The 'belly' or slack in either a rope or wire rope when brought taut will exert 200 lb.s pull.
Additional pulling with a winch or vehichle with blocks will increase this pull. Because the tree is hinged it will not take a lot of force to swing it to C.O.G. of stump.
Kevin's illustration to bring the lean tree to C.O.G. will be very effective.
Andy;
You'll never convince me to make a back cut below the apex.
It doesn't follow the concepts of regular felling practices and can promote splitting and barber chairing.
How high do you rig the pull line, what size is it, and what are you using to pull the line with?
I rig as far up as I can get but with the bottom cut and lashed down good it will work fine as little as 10 or 15% up the trunk. Pulling a tree over and felling a tree are apples and oranges. I would never fell a tree with a low back cut but a tree I am winching/pulling upright I do. I started that after I had a 80 foot eucalyptus in a back yard in Phoenix that I needed to pull so it would fall away from a block fence and adjacent house with a pool between. The cut blew out like the drawing I made, the but end came to the side the line was on (toward the force) and the tree fell backward crushing the wall like a mellon. This snapped the canapé off and that landed in the other guys pool ::) and the but of the log poked a hole in the customers shed wall. I lost some money on that deal and some tonnage off my backside when the guy saw a tree in his pool! :-[ From then on it's belt, spenders and shorts for me! ;)
I'm not out to change your mind, I'm just telling what little I have learned about some of this stuff over my life. :-/ I know you are far more versed in logging than I am but I made a great living off peoples mishaps for many many years and even had one or two my self. :( I enjoy seeing them as long as no one was injured in them but feel like it's my duty to speak up when I see something I have had some hard knocks in like this. What you do with the info is your business, as I bet your all grown up by now. :) I spoke my Peace and I will shut back up now. ;)
Andy
I missed the "what size is it, and what are you using to pull the line with?" part there.
It would be most likely 9/16" IWRC cable and a kevlar covered endless sling at the tree as thats what I have around hear. I don't know what I would use as a deadman or to pull till I get to the job and see the layout. Could be a towtruck, chain comealongs, stacked snatchblocks on the down lines or a thousand other ways depending on what I see once I get there. I have a VHS of me and 8 other guys setting a loaded concrete mixer back on it's wheels with just manpower and a bunch of snatch blocks at a class I went to in Virginia. ;D
Andy
AdField,
I have been pondering your drawings.
In your example of the leaner what happened is the holding wood broke clean across the notch and then the weight of the tree took it the leaning way, and slides the bottom of the tree towards the winch because no holding wood is left. Because there was nothing left holding the tree except the line at the top? So, the tree slides across the stump, until the bottom hits the ground, and then the top seesaws back and forth and broke off and fell in a pool?
With the low cut, you first notch the tree a bit to make room for the saw, put on the chain in a figure 8 with the middle of the chain in the middle of the notch, then finish the notch, then the back cut.
I see the wisdom of sucking up the chain as the tree is pulled.
Because there is so much wood in front of the back cut, the bottom can not kick out, only pivot over the stump in the pull direction because of the deadman lines?
Do I have it right?
You have it. ;) But you missed the part where the but end of the log hit my customer's shed at the end of this sad show. :'( It was a 30" or so tree and looked to be good wood but the force folded 5" of holding wood into a Z shape like so much card board then riped it free of the stump. ::) The drawing is not just right so I will see if I can do it better so y'all can understand it better.
Andy
The wood in the blue box has nothing keeping it from splitting the grain open from the pulling force that can be placed on it when pulling a tree up from it's lean. Then you got a mess if you don't have a plan "B" in place ahead of time.
(https://forestryforum.com/images/04_01_03/cut4_a.jpg)
Andy;
Would you say that wire rope is rated for about 35,000lbs.?
28,000 lbs nominal strength X25% is a WLL of 7,000 pounds for 9/16 IWRC wire rope.
Andy
Andy; why rate it at 1/4 and not 1/5?
Andy,
On the tree you had problems with:
1. What species ?
2. How tall?
3. What was the degree of lean from center?
4. Was your cut- a highback cut with a face cut consisting of a
'conventional' with a 'snipe' as you have pictured above?
5. How high up the tree were you pulling?
6. What angle to the hold back?
7. Were using a vehicle for pulling?
8 Was your face cut as 'deep' as you have pictured?
If your previous pics indicate your problem tree.........I can see why it failed you.
The question I have is ...was is structurally sound or were there signs of deterioration?
My take on it was the line wasn't far enough up the tree and it gave in to a powerfull pull and yanked the bottom out from underneath itself.And I have to agree that the notches you've shown are a barber chair waiting to happen. Workmans Compensation Board would write a faller up for a stump like that around here.
QuoteIf your previous pics indicate your problem tree.........I can see why it failed you
Alrighty, assume, I know it'll be a strech ;D, that I know absolutely nothing. Assume this tree is leaning toward my house. Assume I have the cables or rope hooked up properly at the right heighth and they will hold and pull, as desired. Assume the wood contains no rot or weakness at the spot I'll be cutting. The limbs would be fairly blanced in the top of the tree so a lot of twist due to more limbs on one side than another, etc, would not be expected. How deep and wide would be the recommended cut for the V and why? Exactly where should the back cut be in relation to the V and why? Would, or should the placements of these cuts be the same if it weren't a problem tree as in one out in the open and standing straight that you were cutting for timber? Would this same cut apply to both a hardwood tree, and a softwood tree of similar dimensions? I apologize for still being somewhat confused..
1. What species ? eucalyptus
2. How tall? 80 foot
3. What was the degree of lean from center? 5 to 8 limb heavy on the side I want it to go to
4. Was your cut- a highback cut with a face cut consisting of a
'conventional' with a 'snipe' as you have pictured above? conventional
5. How high up the tree were you pulling? 50 foot
6. What angle to the hold back? Depends what line you count, 2 lines 60 foot out & 50 foot up. The line of force is something like 35 degrees I guess ???
7. Were using a vehicle for pulling? 2 lines off a towtruck, it's a very bad news to use a vehicle in place of a winch :P
8 Was your face cut as 'deep' as you have pictured? I go in about 1/3 of the trunk
Yes it was good wood as far as I could tell!!! We were removing it because it was pushing up the footer of the block fence. The tree guys would not touch it as it was very high risk spot so the tree guy gave the owner my number saying something like "he's got good insurance" and I did. I took a look, rolled the dice and made a bid that came up *raps! :-/ I have given all this info already in this post, didn't y'all read it all? I'm no logger but I have been felling trees all my life and I don't see how I could ever get to trust the wood in a standing tree 100% to keep it off a powerline or house! :-/ Are y'all telling me you never had a notch not do what you wanted or set out to do?
Paul, I did not leave the stump, I pulled it up! If I was in Canada it would be easy to take one more swipe after the tree was down. ;)
And I use a 4 to 1 as it's OSHA overhead standards hear in the US. On webbing, slings and such it's factored in the ratings labels. I don't know on rope as nun is OSHA approved for overhead "lifting" that I have found.
Andy
Ouch,I felt that swipe from here :D
I have seen stumps corrected after the fact and if it couldn't be helped the fallers make an X with the saw and document it.It's the world we live in.
(https://forestryforum.com/images/04_01_03/undercut_falling.jpg)
This diagram I copied from the BC Workers Compensation Board falling manual. The cuts should always be close to the same height and cleaned out.I only knew one faller that was killed by a Barberchair.My Dad knew a few more.
Falling and Bucking (http://www.worksafebc.com/publications/health_and_safety_information/by_topic/assets/pdf/fallers_buckers.pdf)
I've printed off the calculator face page to show my son- he hasn't been around- and I just looked at it and realized that, unlike the original poster, I *wouldn't* know the weight of a standing tree. So I went into the toolbox. Am I right that you'd have to calculate boardfeet and then convert that to weight? It seemed like the info was in there in that form.
Also, I thought I heard Jeff say he put the line pull calculator in the tool box. I'm not seeing it, but it wouldn't be the first time I've missed somthing right under my nose. If anyone can hep me out, I'd appreciate it- is it in there somewhere? lw
Tree weight will take a bit of estimating (without climbing the tree) but could be done using the log weight calculator (gives weight AND cu. ft. volume, and lbs/cu.ft.). Crown size/weight and estimating limb weights isn't easy, and changes for tree shapes. But if the volume in cu.ft. can be estimated from the ground, the weight of the tree can be estimated using the calculator on the left.
The weight from board foot calculations will not include the slab and sawdust piles, which can amount to quite a bit, so will not be a good way to go.
LW;
This is what I use ...
http://www.tenntree.com/images/weightchart.jpg
Andy;
Thanks for the OSHA info.
Here's what I found after digging around ...
http://www.safetysling.com/wr1.htm#chart1
This is from OSHA ...
Wire rope, except as provided in 1919.14(b), shall be tested by sample, a piece being tested to destruction, and the safe working load of running ropes, unless otherwise acceptable to the Administration on the basis of design, shall not exceed one-fifth of the breaking load of the sample tested.
In the case of running ropes used in gear with a safe working load exceeding 10 tons, the safe working load shall not exceed one-fourth of the breaking load of the sample tested.
QuoteAssume this tree is leaning toward my house. Assume I have the cables or rope hooked up properly at the right heighth and they will hold and pull, as desired. Assume the wood contains no rot or weakness at the spot I'll be cutting. The limbs would be fairly blanced in the top of the tree so a lot of twist due to more limbs on one side than another, etc, would not be expected.
1.
How deep and wide would be the recommended cut for the V and why? By 'V' I believe your implying to the face cut which is reffered to as a conventional cut. I do not use this cut but rather a Humboldt cut. Which is a slanted cut upwards on the stump and a straight cut to the corners of the slant.
On any tree leaning to the back of your desired lay, a small face cut with a deeper back cut is required. This will allow for the upper portion of the canopy to be pulled beyond the stumps center of gravity.
If you look at the post that Paul H. submitted it depicts a picture of a conventional cut and a slightly forward of center holding wood. This would be ok for a fairly straight stem, but not for a back leaning tree.
Face cut should not extend 1/3 the diameter of the stump.
2.
Exactly where should the back cut be in relation to the V and why? Back cut should be one to two inches above the face cut.
3.
Would, or should the placements of these cuts be the same if it weren't a problem tree as in one out in the open and standing straight that you were cutting for timber? Depending upon size of the trees you were falling. With a fairly straight up and down tree the face cut could be deeper as pictured in Paul's post. However if it is a small tree you may not have room for a wedge with a center or near center face cut.
4.
Would this same cut apply to both a hardwood tree, and a softwood tree of similar dimensions? Yes and No......There are other variables to consider when falling different species.
Fast growing hardwood trees have different shear levels and are proned to split or barber chair rapidly. (e.g. Locust, Silver Maple)
Also, different species are attacked by different organisms, some are more proned to heart rot, sap rot, root rot and subjected to severe weather, mechanical disturbances.
When falling a tree.....determination of wood soundness should be ascertained before falling.
Hopefully cleared up some of the confusion. But probably gave you more to think about :P
NOTE: .I have modified my post on page 3 you may want to look at it for more info.
QuoteThe tree guys would not touch it as it was very high risk spot so the tree guy gave the owner my number saying something like "he's got good insurance" and I did. I took a look, rolled the dice and made a bid that came up *raps! :-/
Wow :o "tree guys" without insurance !!!! Does not sound like any bona fide Tree business.
He's got insurance, he just wanted to get back to trimming palms and making fast money not tinkering with a spooky tree like this one. He also knew I had $5,000,000 liability as his company had a proof of my insurance and work-comp on file for when we worked state jobs together. In other words he knew if I messed up (like I did) his business would not get dragged into it, he's no fool, I was his plan B.
Andy
QuoteLW;
This is what I use ...
http://www.tenntree.com/images/weightchart.jpg
Kevin, Thanks for that! I printed it right off as well as saving it in favorites and images.
I know I never had that data in that form before. It's highly entertaining to picture the trees/logs together and 'feel' the difference in weight. I mean, when would a person really get to do that in all the variety? The most I've had together at one time is maple, oak, and pine- and not always green. Hand-splitting is nicer if it's dried a while, esp if you have the tendency to get the chunk wedged onto the axe and then have to turn it around and split it backwards. lw
QuoteLW;
This is what I use ...
http://www.tenntree.com/images/weightchart.jpg
Don't mean to be picky, but the first column of this useful table referred to here is "Weight per cu. ft." rather than the heading of "Weight per linear foot" as is shown. The remainder of the table is 'weight per linear foot' by 2" diameter classes. I noticed that the average green moisture contents are used so the numbers are more accurate in estimating the green weight. But it is still an estimate.
Cktate,
*ADDENDUM*
Just realized that I also may have left another important factor left unsaid.
The amount of holding would depicted in Paul's post is to little for elevating a lean tree of comparable size as pic'd in that post. 2" would be more realistic.