Back Leaners - Part 1

A look at the forces involved, and required, to pull a back leaning tree back to vertical and why things often don't go well.

[@tatdexter2334]

I found you while searching for info to remove a black cherry that had fallen on my house - mission safely accomplished, thanks! Secondly, I''m a mechanical engineer and appreciate the logic and calculations that go into your explanations. This has convinced me to call in a pro to remove a second, larger, severe back leaner. I was tempted to give it a try until I watched your entire series and realized it was beyond my capabilities.

[@terryhale9006]

Tat, Thanks for the report! Always nice to hear from an appreciative engineer.

[@stroys7061]

Hands down this guy does the best instructional videos.

[@jsbounds27]

If we taught our kids in school today with examples like this we would have many more paying attention!

[@fatcapital88]

Terry this content is amazing thank you so much for doing these videos. This is by far the best explanation I've seen anywhere!

[@terryhale9006]

Thanks!

[@lashlarue7924]

This has got to be the absolute best tree-feeling content on all of KZbin. Buckin' Billy and TreeSon are great for hands-on, but this goes deeper into the engineering of it all. Folks, I think the main reason you hire a pro to handle a backleaner around a structure has to do with three words: "Licensed, bonded, and insured". Even though we may not be completely incompetent, the decision to tackle certain trees around one's own house would be akin to performing your own brain surgery - only the foolhardy would ever attempt it. Terry thank you so much for sharing your considerable expertise with us, thank you from the bottom of my heart.

[@RockhillfarmYT]

Your videos are fantastic I have watched most of them more than once

[@domainxh]

Great video, it's really nice to apply physics to a real world problem. This will make a good physics problem for high school students! Thanks for sharing and taking the time to work out the math!

[@terryhale9006]

You're certainly welcome. I can almost picture students frowning in concentration.

[@PhilJonesIII]

I had a back-leaner on a 45-degree slope that was threatening my neighbour's house. The house-insurance had a very specific exclusion for this type of situation. If it falls on someone else's property then it's your pocket. I watched the guys working. It took several hours. They cut it down piecemeal and their swinging-free on ropes while waving those saws around drained my confidence by the minute. I couldn't decide if this was a pair of amateurs that were oblivious to danger or supreme professionals that just made it look easy. Still, I was glad when the job was done. I'm so glad I watched this video after I employed them. My nerves would have cracked minutes into their work. 16th century, stone farmhouses with slate-tile roofs are no less vulnerable to ancient oaks falling out of the sky.

[@terryhale9006]

Sorry you had to deal with that expense. Sounds like a damaged house would have been a lot worse.

[@PhilJonesIII]

@@terryhale9006 I didn't mind paying. You guys are worth the job well done. Hitting that house would have seen me with a one-way ticket to a distant land where no-one knows me.

[@oq17]

Hi Terry - I really enjoy your videos . I’m a mechanical engineer and I appreciate how you have laid your your free body diagrams, assumptions and explanations . Thank you

[@terryhale9006]

Thanks RJ. Nice to hear from a fellow engineer.

[@wryipx]

lol. LOVE the physics! Yes, pulling by hand or truck can verge on stupidity, especially due to lack of coordinated control. Wedging changes this "significantly" but does not remove the stupidity. ... planking, barber chair, hinge failure, LOVE this series ! Great work !

[@terryhale9006]

Thanks Wry!

[@charlesjarmanii]

I love the math you are using in these videos. Thanks it was very helpful in understanding how the forces are being applied.

[@terryhale9006]

Thanks Charles.

[@mikejames9931]

Thanks Terry I got a Leaning pine tree to cut down in the next few weeks.Great video and Thanks for the Help!

[@terryhale9006]

Thanks, Mike. I hope you get a cool, overcast day with little wind.

[@destravlr]

Love your title. Wish I'd have seen this before I botched the job of felling a large ash in the back yard. Was lucky I wasn't killed. The stake anchoring the rope "holding" the tree shot out of the ground as the tree suddenly fell. The conclusion was replacing our common fence, removing the tree in their yard, and replacing the two plastic flamingoes that were crushed.

[@terryhale9006]

Seemed accurate.

[@edwinkubena9944]

Opened my eyes on cutting trees! Tanks!

[@felipeecheverri4225]

Awesome job Terry! I just geeked out like crazy!

[@treemankyle]

some great videos Terry its nice to listen to the more scientific side for a change

[@terryhale9006]

Thanks Kyle. Stay safe!

[@Scott64a]

thanks, Terry. even without the trigonometry involved in calculating the forces involved in cutting severe back leaners, this video prevented me from trying to fell a twin trunked white oak. it was back leaning, and i wasn't going to attempt it once i watched your video. i have decided to leave the tree. :)

[@terryhale9006]

If the video helped you make a good choice, I'm glad. (Plus, I am partial to white Oaks.)

[@reevox]

Thank you for the math! I am a Biology graduate and am currently helping out a woodworker gathering some lumber for summer projects. I now grasp the reality of the forces needed to bring down a leaning tree where you want it (No, I was not holding the rope at the time)! Refreshing to see the math I learned so long ago working FOR me!

[@terryhale9006]

Made me laugh about the rope holding.

[@stevenbrown5210]

You got a degree in biology so you could gather wood 🪵?!?

[@ranger9248]

Very much specific information about the forces. Thank You!

[@terryhale9006]

Thanks Alf.

[@keithcarlson6038]

Very interesting seeing this all worked out! Reminds me of Statics class many years ago. Now, on the practical side, it would be great if someone could recommend a simplified rough calculation to help determine how much pull you might need if you really wanted to pull a leaner back the other way. Something just involving the estimated height of the tree, trunk dia at breast height (I believe that's a common measurement), and lean angle. And since it's a rough calculation, recommend a factor of safety for the pull force. So that out in the woods, you could quickly estimate how much force, multiply by the FS, then decide whether you think you have the right equipment to try that approach.

[@terryhale9006]

The beauty of being out in the woods, though, is that you should seldom have need to make a tree fall opposite to its heartfelt desire.

[@scatbacker]

don't forget Temp, and barometric pressure in that calculation...plus x-ray the tree for any insect damage or rot and bad growth rings and add that in....:)

[@steveeaton9126]

I love how your figures underscore how we don't appreciate the forces at work. That should refresh our healthy hesitation in every tree falling situation!

[@terryhale9006]

Thanks Steve. I'm trying to look out for those who bought a chain saw with "How hard can it be?" on their mind.

[@jimfiorentino7741]

Terry.. Love the math. Thanks. Wasn't hard figuring that you were an engineer. Only an engineer would weigh and record the position of pieces of the tree to get the center of gravity position. Not to mention such a dry sense of humor. I wonder why back leaners have such a propensity for growing near houses. Wish that I'd paid attention in geometry class enough to calculate these things. Thanks Terry. Love the series.

[@terryhale9006]

+Jim Fiorentino Thanks much Jim! Wouldn't have done the weighing and c.g. calcs, but I really tried to find some decent numbers on the internet and was surprised that they weren't available.

[@penfoldooo2160]

+Jim Fiorentino Plants grow in the direction that will allow them to capture the most light. If a tree is on the edge of a clearing, it will have canopy blocking light on the forest side and nothing blocking the light on the clearing side. It will thus grow/lean into the clearing to get more light. Humans then come along and build their homes in clearings. A tree growing in the middle of a thick forest will almost always grow straight. That's why plantation trees are planted with such close spacing - if you block the light to the sides, the tree has no option but to grow straight up if it wants sunlight.

[@dpeterbannister]

Great video Terry. Thanks for the post.

[@alexbeedie6940]

I love the fact you know the friction resistance of grass

[@terryhale9006]

In my regular job, I'm an expert on roadside design. I occasionally get consulted on cases where cars go off the road and the distance they travel is affected by numerous factors, including the friction on the pavement and the friction on grass.

[@alexbeedie6940]

I wondered where you got your physical engineering knowledge from. it's great to see the mathematics evolved I think it help make my estimations more accurate.

[@RKarabeckian]

You're cool. Keep up the good work and thanks buddy.

[@henryrollins9177]

Thank you very much! really helpful videos ... cheers from Patagonia!

[@terryhale9006]

Thanks Salame. I know it won't happen, but it would be nice to see your forests. Your forest climates are similar to our mixed forest climates here in upstate New York, but I'm sure the species are very different. Cheers!

[@ChemBioTeach]

I have a landscaping business and I also teach high school bio and chemistry. However, I love physics and I really appreciate and love thw math you include in your videos. Great videos! Very very informative!

[@terryhale9006]

Thanks Teach! Keep up the hard work!

[@AxcelGamer97]

Man I wish I had you as a teacher in high school then.

[@abrogard]

You are a beauty, Terry. Wonderful. :)

[@obfuscated3090]

Wonderful explanation of the forces involved. I often secure a snatch block to another tree then run my winch cable through that so my truck is well away from the furthest the target tree can reach. Of course no common winch can spool quickly enough to guide a tree most of the way to ground but driving can do nicely if there is room. If it seems wise I'll use another cable anchored to a different tree to help control the fall. I never "snatch" a cable on trees or vehicles because that's foolish and dangerous. (Quite a few off-roaders lose windshields to such dumbassery.)

[@terryhale9006]

Yes, but they make great KZbin videos!

[@toddjacks8288]

Awesome video brother

[@OmahaLasse]

I love the maths approach! Exactly my cup of tea!

[@JustonianInstitute]

This is fantastic.

[@terryhale9006]

Uh...Thanks Juston.

[@mikebroek5543]

Awesome presentation! This would be a great statics example for engineering students, good stuff. To take it even a step further, someone could apply a stress concentration factor when calculating the bending resistance of the hinge. The square cuts, like the ones made by chainsaws, induce crack propagation by a sizable factor in most cases.

[@terryhale9006]

Thanks much, Mike! To further complicate matters, crack propagation gets really complicated by the highly anisotropic nature of the material.

[@Gr8tBlueHeron]

This video was insanely helpful, thank you! As much as I hated trigonometry in school I'm glad someone paid attention!

[@terryhale9006]

Thanks, Big Bird. If you say it was helpful, I'll hope your project(s) went well.

[@Gr8tBlueHeron]

@@terryhale9006 it did! Took down a few leaners, two of which were made complicated by rot. But thanks to this video we employed the truck ropes and angles in such a way that they all worked perfectly! Now, making the cuts on the other hand... Folks in the videos make it look so easy, but getting the cuts just right definitely takes practice! One of them took way more wedging and hammering than it probably should have...

[@terryhale9006]

@@Gr8tBlueHeron Excellent! Just passed 70 and discovered my balance is fading. I'm starting to have trouble getting my cuts properly oriented. Getting old sucks.

[@Gr8tBlueHeron]

@@terryhale9006 oh no! Well, at least you got the skills to pass on and can instruct an enthusiastic youngster in proper technique! And I sure appreciate your willingness to share your knowledge with us random strangers!

[@nataliedeyton6829]

You know my favorite way of taking down back leaning trees ? Rope in top and T250 bobcat pulling it down 🤣 I really do like the in-depth video tho

[@terryhale9006]

If ya got it, flaunt it!

[@stephenliverman815]

really enjoy your teaching

[@terryhale9006]

Thanks Stephen.

[@231flash]

I knew I should have paid more attention in math class.

[@terryhale9006]

I wish all math, chemistry, and physics classes were taught using pretty much nothing but practical problems.

[@kleffner123456]

This guy could be BS and would have no idea.Sounds convincing.

[@bryanfife2706]

@@kleffner123456 just spend some time around tree cutting & you'd have clues

[@444gtb]

Thank you for sharing. Very interesting.

[@terryhale9006]

Thanks, grb.

[@marka9292]

Very informative video. Thank you.

[@terryhale9006]

Wow! You're quick. Thanks for the nice feedback.

[@marka9292]

I was watching it as you uploaded it. ;) joking.

[@_DMAC]

6:00 I LOVE the physics being explained! So much better to learn the why behind the how.

[@terryhale9006]

Thanks again, D!

[@lamoinessnow4708]

Very good video.

[@ottard]

Hi Terry! What's your take on using a bottle jack to push a tree over? I have a 8800 lbs (4 metric ton). If the moment needed to tip the tree is 5400lbft (from the example in the video), I would need a 18cm moment arm at 4 tonnes. If my chinese jack is able to produce the stated 4 tonnes, that is. Is it safe to exert this amount of upward force (of cource using a top plate to spread load) to the trunk?

[@terryhale9006]

I've never done it myself, but it is fairly common European practice with large trees. A key detail is to use a fairly thick steel plate above, and often below, the jack to distribute its force over a larger area to avoid punching into the wood. The usual process is to cut the notch, then cut a pocket into the side of the tree opposite from where you want it to fall, insert the jack and plate(s), then pump the jack, followed by finishing the rest of the back cut.and additional jacking as needed.

[@ottard]

​@@terryhale9006 Great! I'll give it a try then, once I get my hands on a piece of thick plate. I want to fell some spruce trees, in an area that I cant reach with my 2WD tractor with winch.

[@jcstevegigs]

Great video! Thanks

[@terryhale9006]

Thanks Steve!

[@jtjones73]

These are great videos, thank you. I did have to laugh though at 7:10, "so what does the tree experience from that tension?" Not a damn thing except maybe a laugh as it sends the guy flying through the air when it falls.

[@terryhale9006]

Thanks Jeremy. I occasionally like to credit personality and thought to other life forms.

[@elricofarmer1561]

Good stuff, very enlightening!

[@terryhale9006]

Thanks, Eric!

[@liviuholca6136]

Sir, your knowledge goes well beyond the one of a professional tree feller. I doubt you make a living cutting trees.

[@terryhale9006]

Caught me. I started cutting trees and removing stumps when I was 8, but chose Civil Engineering and computer programming over Forestry.

[@scatoutdebutter]

What kind of and language(s) computer programming, sir?

[@scatoutdebutter]

Let me guess which languages.... Assembler, Fortran, and maybe C. am i close?

[@scatoutdebutter]

... and possibly BASIC or RPG depending how long ago he took up computer programming!

[@terryhale9006]

I started using APL in 1970, then Fortran, BASIC, Visual Basic, VBA (in Access, lots of those), and a couple of JavaScript apps. Now, I'm mostly using ApEx and PL/SQL. All are exercises in patience.

[@scatoutdebutter]

Mr. Hale, do I understand correctly in the example that what needs to be overcome for the tree to fall forward (back lean + hinge) is 216# horizontal force ? ... and that the rear wheel drive pickup in grass can exert 650# horizontal force on the tree ==> *therefore* in this situation the pickup IS able to pull the tree over with 434# horizontal force to spare, right? ... AND in the 2nd example with the 24" DBH Ash, the 4WD on asphalt can easily handle the 1400# horizontal force to pull it over ----- Am I understanding the math and physics correctly? Thank you!

[@terryhale9006]

Correct.

[@shopnwoods9901]

Great video. Doesn't that book mean a 2x12 on edge? As used for a floor joist or rafter? Not bending flat ways

[@terryhale9006]

It provides properties for each direction.

[@shopnwoods9901]

@@terryhale9006 OK. That would be a great book to have.

[@terryhale9006]

@@shopnwoods9901 Mine is pretty old, but I doubt the numbers have changed. You could probably get a decent secondhand book on Amazon for a fairly low price.

[@shopnwoods9901]

@@terryhale9006 I'll take a look around. Thanks

[@mrannunaki6852]

I love the mathematics applied here.. Do most arborists calculate their job to the perfection of this?

[@terryhale9006]

I'd say they never do. With the uncertainties involved, it is just easier to take a guess at what's needed and provide much more than what is needed. Bad things happen when the guess is way off and only what was assumed sufficient was provided. Non-professionals often don't have the experience to make either judgment and then have events that may end up on KZbin in an unflattering context.

[@murphy4trees]

Terry I like this video more every time I watch it... I do think you significantly underestimated the weight of the tree... A medium tree like that weighs a lot more than one ton.. maybe 3-5 tons or more... Take a LOT MORE than one or two big guys to pull a backleaner like that over. Would also be interested in how the numbers play out with the height of the pull line. I like to go VERY HIGH with my pull lines.... top of the tree

[@terryhale9006]

+Daniel Murphy Thanks Dan. Must be the face in the window. I agree on the tree weight. Just wanted to work with a nice round number. You are right to get high with your pull lines. However, unless you can get farther away at the same time, most of the extra height will just be wasted as vertical pull. If you can fasten your pull line twice as high and be twice as far away, you will be pulling at the same angle and exerting twice the overturning moment. Viewed another way, if you have twice the height and distance, you will only have to exert half the force to generate the same overturning moment.

[@TheMadMagician87]

You have a number of 4.219 cubic inches for the section modulus, how was that number derived? I'm assuming it's something to do with the hinge dimensions of 11.5" x 1.5" x (something). Is something a 'height' dimension taken from somewhere in the notch?

[@terryhale9006]

You are more or less headed in the correct direction. The formula is Section Modulus (S) = b times (h squared) / 6 , where b is the 11.5", and h is the 1.5". This gives 11.5 x 2.25 / 6 = 4.3125. The Timber Construction Handbook may be making deductions for the rounded-off corners of most real-world 2x4 lumber to arrive at the slightly lower 4.219. Trying to describe the derivation of b x h x h/6 is pretty tough without being able to use a diagram. Given that difficulty, I'll only give it one shot. Imagine a board 1.5 inches thick that is being bent to the point it will rupture. Ignoring the anisotropic behavior of wood and its non-linear stress-strain curve, we can assume that, at the moment of rupture, one surface is at the maximum tensile stress while the other is at the maximum compressive stress. Further assume that those maximum strengths are equal and that the stress varies linearly between the two surfaces. (We're already well away from reality. but you sometimes have to make simplifying assumptions to be able to do reasonable calculations.) That would mean that the stress would be zero at the neutral axis (dead middle) of the board thickness. On either side of the neutral axis, the stress would increase linearly from zero to the maximum. Each of these stressed areas would extend out from zero at the neutral axis to half of the thickness of the board, or h/2, where the stress would be the maximum. Let's call that maximum stress Fy for the stress at yield of the board. Looking at one of these stressed areas, it is in the form of a triangle where one side is h/2 and the other is Fy. The formula for the area of a triangle is 1/2 the length of one side time the length of the other side, giving an area of Fy x h /4. On average, this area of stress (tension or compression, depending on which side of the neutral axis) will be acting at 2/3 of the distance between the apex of the triangle and the outside surface of the board. The stress will be acting at 2/3 x h/2 or h/3. The moment that each stressed area will be providing to resist the bending of the boars will be the moment arm (h/3) times the sum of the stress (Fy x h/4). Multiplying, that gives us Fy x h x h /12. However, there are TWO stressed areas, one in tension and one in compression. Adding the two moment contributions, we have Fy x h x h /6. So far we have only been considering the section of the board. Toe capture its real moment resistance, we have to also consider the board's width, b, which is equal to 11.5" in our example. When we multiple that in, we get Fy x b x h x h/ 6. That is the classic solution for the maximum moment capacity of a rectangular solid. It consists of two parts, the maximum stress of the material, Fy, and the Section Mdoulus, b times (h squared) / 6. Engineering text books have accumulated the derived section moduli for many different sizes and shapes of possible beam cross sections. While most engineering graduates have gone through some of the basic derivations, I'm pretty sure most who are in practice simply use the manuals and have probably not done a derivation since college. If you like frustration, you can try to draw out the diagrams to make the above derivation make sense.

[@TheMadMagician87]

@@terryhale9006 Thanks for that, all makes sense given the assumptions/simplifications of the model. As you say, reality is a whole different beast, but a simple model is always a nice tool for helping one wrap their head around the magnitude of scalar or vector quantities that they are going to be doing battle with. Really appreciate the amount of time you have taken to provide that answer, and to have answered so promptly!

[@terryhale9006]

@@TheMadMagician87 Thanks and welcome, MM.

[@TheMadMagician87]

@@terryhale9006 For anyone else that's interested, Terry has another excellent video that looks at the details of the hinge: kzbin.info/www/bejne/nKHEfKKieryrfZY

[@5herwood]

I need to cut some big ash on a steep hill. It is hard to have a good escape rt. in many cases. Any advice?

[@terryhale9006]

Footing on a hillside can be really treacherous, especially with lots of fallen leaves on the ground. You didn't mention whether there were any constraints on the direction you could fell the tree. In a wooded area on a slope, most branches will grow towards light, which means up and away from the slope. If that direction works, an escape route along contour is best. Whatever direction you are felling the tree in, if the escape route is tricky, you want to be away from the tree when it begins to fall. A good way to do this is to get a rope up into your tree and run it to the base of another tree which is in the general direction you want the tree to go. Fasten a pulley to the base of this second tree and run your rope through it. Then run your rope back towards the tree you are cutting, but off to the side to your safe retreat area. Cut your notch and part of your back cut. Stop and give a pull on your rope. Do a bit more cutting, then try to pull it down again. Eventually, you will reach a point where the hinge is strong enough to keep the tree from falling, but not strong enough to resist your pull. At that time, you will be in your safe place and the tree will fall. Make sure not to leave the rope in tension when making your cuts.

[@5herwood]

Thanks.

[@LadDox_]

When do you plan to upload the video on the cure for cancer??? Good lord you are a genius

[@johnnywishbone932]

So what you are saying is my buddy is not strong enough even if he has wings, beer and skips leg day at the gym?

[@naturefamily]

Awesome, very informative. Thanks !

[@naturefamily]

I think you're looking at the 2 x 12 wrong. In a structural book it it the edge (12") direction that is specified which is WAY more than the flat (plank) direction.

[@terryhale9006]

Nat, You are correct that there are big differences in a beam's capacity, depending on whether it is being bent about the weak or strong axis. With a felling hinge, we are bending about the weak axis, The formula for Section Modulus is (BxHxH) / 6. For weak axis bending of a nominal 2x12, B=11.25" and H=1.5". Running the numbers, the weak axis section modulus is 4.219 cubic inches. If we are interested in bending about the strong axis, we would reverse the B and H measurements and get a Section Modulus of 31.64 cubic inches. This shows that our assumed hinge has 7.5 times the capacity to resist side lean that it has to resist falling.

[@GeirGJohnsendto]

What's the best climbing Spurs?

[@terryhale9006]

I won't claim to have enough experience to be able to give a good answer. For the part that goes through the bark, the actual spur, you want a length that is appropriate for the trees you will be climbing. For most trees with average bark thickness, you want a normal length spur. There are some trees that have very thick bark, two or more inches thick. If you will be climbing those, you want long spurs to get deep into or through the bark. Since bark is a lot weaker than wood, you don't want a short spur that is just an inch into some weak, platy bark. For what fastens around your calf, you want something that is easy to put on. Mine are older and not easy to put on. Some sets are designed to be light weight, but are more expensive because of that. As you are usually standing on top of that weight, I have not considered it an issue. My simple advice would be to make sure the bit is the right length for what you need and then get a design that looks like it will be easy to put on.

[@johnbruce5107]

There was 3 fellas looking at it, were they tree fellas?

[@dereksmith4791]

Thanks a ton for these videos man, gotta say that your display of from-the-inventory gear (beautiful, beautiful gear, drool ;P ) has me wondering if you're not an owner of some retail operation? It's only interesting because I don't see company-names and would think you'd want the good-will from this channel aimed at something *if* you've got wares to sell (I'd be more likely to buy from you, have learned a ton watching your felling series!) At any rate I like the phrase "underestimating what's required to take the tree down & overestimating one's strength" however I've actually found an oddity am in-the-middle of fighting-down a large leaner in-yard and have got 2 ropes with 2 people, dogged the heck out of it (plunges from all sides and a ~40% depth notching, wedges etc) and the thing won't come down we're going to use a truck today (got dark on us last night, wasn't expecting it to give a tenth this much resistance it's a Live Oak though..)

[@igneous061]

love the sence of humor :D

[@terryhale9006]

: )

[@patrickallen4120]

Good video!

[@terryhale9006]

Thanks, Tim!

[@scatoutdebutter]

Mr. Hale, I believe you included an extra digit on your "Net Weight" in the slide around @ 12:40 .... you have 14139#, but I think you meant 1413# Not trying to be a wise guy, but I wanted you to know someone was paying some attention to the math!

[@terryhale9006]

Good catch! Darn typos.

[@brentdarrin1109]

My father was a nuclear Physics instructor and I don’t think he would’ve made such a simple problem as complex I’m not at all saying that it cannot be a complex problem but it doesn’t have to be. it is simple, If your homeowner taking down a large tree that’s leaning towards something valuable just know your place stay in your lane hire someone don’t want to listen to good advice I’ll have fun paying the contractors to fix your house or the ER visit look I didn’t have to use any math

[@DIESELMAN8V92]

very well explained

[@timberray9572]

If you have a two wheel drive truck you should tie the rope to the front and pull in reverse, this will lift the front of the truck and actually put more weight on the back tires, giving you more traction.

[@terryhale9006]

+Ray Duerksen Correct.

[@_sunsor]

+Terry Hale Are you sure this is correct? I do not see how weight would be transferred to the rear axle in the front-pulling case. The weight "lost" by the front axle would be picked up by the tension in the rope, not the rear axle.

[@terryhale9006]

The rear wheels do the pulling. They are limited in how much force they can apply horizontally by how much force is applied to them vertically. Therefore, as one factor, not having the rope's pull lifting on the back end will mean they can be more effective. As the second factor, the rear tires have no idea what is holding up the front end. However, they can tell WHERE the front end is being held up. Looking at extremes, if the front tires were directly under the truck's center of gravity, those front tires would be taking all of the load and the rear tires would have no load on them. At the other extreme, if the front tires were attached way ahead of the truck by some long, lightweight frame (think drag racer) nearly all of the weight of the truck would be on the back tires and the force they could apply would be maximized. When you pull with the front of the truck, the rope's force is being applied several feet ahead of the front tires, so some of the truck's weight gets transferred to the back tires. Considering that the engine is a significant part of the weight, the amount of weight transferred to the back is not trivial.

[@_sunsor]

In my haste I assumed that the tension force was applied at the front axle. A simple moment balance confirms what has been said when the tension force is not applied exactly at the front axle. Thanks for your time!

[@terryhale9006]

You're certainly welcome. An understandable oversight.

[@Mrcheckitout100]

Rainman with a chainsaw. Nice work!

[@TS-xj5mt]

Brilliant

[@Jdake801]

I’m not sure why the puller seems angry? I’m 6’3” and if I was only 200lbs I would be smiling like an idiot. Thanks for the info!!

[@abrogard]

someone show this to bucking billy ray or treeson and ask them what they use for a 'ready reckoner' on what's required to down a specific leaner...

[@iditarod4081]

Bravo!

[@davidkarstensen9677]

I aced Trig and Calc, but I mustve forgot.

[@terryhale9006]

Probably that nasty "Use it or lose" thing. I remember that I took two years of French, but that's about all I remember from the experience.

[@7.62fullmetal9]

would not the friction of the grass depend on whether it is clover or Kikuya and wet or dry, also if it has been fertilised recently this could swell the cellular structure of each blade thus increasing the amount of friction?, of course I am only an ametuer.

[@terryhale9006]

Questions that have plagued Accident Reconstructionists for decades.

[@7.62fullmetal9]

I will keep working on it Terry, but seriously that was some fine maths my friend. Excellent vid. Chhers

[@terryhale9006]

Skip the math; enjoy the cutting.

[@justcorylee]

what about chain falls to a good anchor

[@terryhale9006]

Cory, I have no experience with chain falls. I don't see a good reason why they couldn't be used for this work. Just want to keep them out of the dirt, Terry

[@dunnkruger8825]

Thanks

[@ronaldwilkins6056]

"Out in the forest you can change a back leaner to a leaner simply by changing the direction you want it to fall." Lol...I wish that also applied to my neighbor's pine trees that are within striking distance of her house.

[@bobbeaver983]

two pulleys, three ropes, two come alongs, hold my beer..... sign this.....

[@terryhale9006]

Please. It's a six-man operation. Three to operate the three directions and three men to hold their six beers.

[@mobilechief]

Use a backhoe properly and no issue if you have the room.

[@josebenitez3732]

Hey Terry, You should have mentioned how the tree would become a trebuchet and launch the puller into orbit.😆😆😆 NEVER wrap load lines around anything you don't wish to lose (hands, arms, legs or waist)! I'm always amazed watching KZbin videos of people wrapping fishing lines, ropes, etc. DON'T DO IT!!!

[@terryhale9006]

I considered that one example of "an interesting trip". ; )

[@jmecillakennedy7102]

Nice calculations no Id like to see you personally cut it down math man.

[@terryhale9006]

kzbin.info/www/bejne/iou9d42Oiah3mrs is the closest I can get you on that.

[@mattcomchoc2957]

+Terry Hale in your ash example where you figured out the CG, you don't mention how tall the tree was in total, just that the CG was 30' up.

[@terryhale9006]

+Matt Comchoc I still have that notebook someplace. I'll see if I can find it.

[@kodfkdleepd2876]

But where's the calculus? Maybe a few differential equations would be nice! ;)

[@myster.ejones1306]

Man vs Tree tug of war. Hahahahahaha! 😂

[@jamesjahoda1613]

A grinder on a boom. Wouldn't it be nice if it were that simple!

[@terryhale9006]

+James Jahoda They actually do have those! I've seen videos of them munching into a conifer and then chasing the trunk all the way to the ground. It seemed like it took about 20 seconds to destroy a 70 foot pine tree. It left one big scattered mess, however.

[@jamesjahoda1613]

Thanks for the reply. I have a friend with a grinder on a skid steer. Hard to imagine it on a boom. I sent your Back leaners -part 1 to a young cousin in college. I think he will be beside himself with joy with the math. Nice going.

[@terryhale9006]

"Young...in college". That makes you old like me.

[@jamesjahoda1613]

Heck yeah. Still getting it done. Good luck with everything. Thanks for the great work. I imagine you spent a lot of time working on this. It's so dry, informative and hilarious. You are appreciated. I'm scanning youtube for safety refreshers. I'll be cutting up a fallen tree on my friends farm tomorrow.

[@jamesjahoda1613]

P.S. College cousin says COOL!

[@seanpcurran2011]

45 tears ago I was trying to figure out just why the hell I was taking trig. The professor looked exactly like Albert Einstein which made it fun and interesting at times, but if someone had told me "...and you will get killed trying to do a half assed job of felling a tree in your back yard." Yeah, listen up good. Did I save notes... O.o ?

[@scatbacker]

Ok, now treework is rocket science...sshhh....don't tell everyone.

[@hans-jurgenwiegand7465]

You sure opened my eyes! I’ve been very lucky, & didn’t even know it. The worst thing a person can ever do, is get in a situation, that you don’t know how dangerous it is! That’s killed many a person, in all occupations. I just realized I might be better off selling my chainsaw!😳😱😥

[@terryhale9006]

I've been lucky, too!

[@HectorRodriguez-fl5dm]

No trees were harmed in the making of this video.

[@terryhale9006]

It's tough to get my wife to condone a tree murder.

[@levilinton2928]

I almost fell asleep lol

[@terryhale9006]

And it wasn't even past midnight. I'm crushed!

[@JanThorCrow]

They have yet to make a chainsaw that is or was designed to be used with one hand. 2 hands on that saw.

[@terryhale9006]

Trying to. I also need to spend more time getting into good positions to facilitate the use of two hands.

[@JanThorCrow]

Practice moving around & positioning while leaving the saw on the ground. With your attention to detail, (over time), it will become easier and more intuitive.

[@terryhale9006]

Sounds reasonable. I'll give it a few climbs.

[@janfilipczyk2994]

Titulky mají být přeloženy do češtiny, pokud jsou určeny pro Čecha /nebo Slováka/, nebo by bylo vhodné i přeložení do slovenštiny, protože tento jazyk by byl pro Čechy také srozumitelný. Ta angličtina kvůli nutnému stupni znalosti toho jazyka, není srozumitelná, odhadují pro 95 procent, možná ještě více posluchačů, takže pro mně zůstůává záhadou, proč tohle video ještě nikdo nepřeložil do češtiny nebo slovenštiny.

[@frankburns8871]

I think the trees that decide to be back leaners due to the fact that they're near a house or other valuable structure, probably consider themselves "front leaners." It's totally kingdomist to ascribe "back" to their leaning leanings.

[@terryhale9006]

Point well taken. I will try to be more sensitive in the future.

[@frankburns8871]

Well alright then. Just remember to check your animal privilege...and keep up the excellent videos; they're entertaining and educational, and may even save a life or two.

[@terryhale9006]

That is my hope.

[@426superbee4]

left out one a safety net he heee

[@terryhale9006]

The older I get, the more that sounds like a good idea.

[@426superbee4]

he hee i know a limb came back on and fell out of the tree. It was fun tho The grass was thick. wanted to do it again

[@seenonyoutube7856]

This is kinda interesting if you're into physics and engineering. However, I think an experienced tree remover is going to cut those trees down without adding so much as 1 + 1. You can't beat experience and the proper equipment for getting the job done.

[@terryhale9006]

True. The series is intended for those who do not have a lot of experience and would like a detailed explanation of what they may have problems with when approaching what may be a risky situation.

[@monkeysgonna5306]

Why of course I became a logger because Im good at math

[@terryhale9006]

Another in a long line of great mathematicians who decided they'd rather do something fun with their lives.

[@kleffner123456]

Einstein lumberjack.

[@terryhale9006]

Alas! I fall well short on both.

[@dsnicker9719]

Screw it. Hire a trimmer (with liability insurance)!!

[@stephengmeiner3264]

I feel dumb!

[@terryhale9006]

Engineering stuff. If you're not an engineer, a fair bit of that SHOULD be unfamiliar.

[@shaneroper477]

Good grief! Didn't know you had to be the equivalent of an astro physics major to pull down trees lol! My moto...go big or stay home. In other words, get a dam strong rope if your pulling over a dam big back leaner. And, of course, use your judgement.

[@terryhale9006]

Almost always an effective strategy. The video is intended to be a "heads up" for homeowners who might be tempted to use a lesser rope and to rely on some less-than-overwhelming means of pulling on the tree.

[@rodfather8425]

I have a landscaping business in central New York and we like to do trees. Been doin it for years we climb and lower trees and pull leaners also. If we can’t use the machines or pickup to yank a big one, we use 45* angle and drive a pin into the ground, useing as a minimum about 2/3 the height of the tree for the distance from stump. Attach a pulley to the pin and then use the pickups. I been doin this a long time but terry is still the man. Love your vids terry

[@arneboveng3756]

Gotta laugh just a bit with all the trigonometry and tech terms like moment and other physical principals, yet no talk of specifications for the rope. He has elected to use a dynamic climbing rope, not a static rigging rope. Watch it stretch when he pulls. Now you need to add in duration into your formulas. Dynamic rope will be very much less effective for this purpose.

[@terryhale9006]

Covered in a different video, Pulling Trees Down with Rope.

[@arneboveng3756]

@@terryhale9006 Yeah, I saw that after I posted. Thanks. Question though, why would you have a dynamic rope involved in any example, tied to a tree, unless it was being used in a climbing (not ascending) situation where falls were to be expected?

[@mxfern12]

Moving the house would be easier than solving the math equations,🙉😫