fun with math (trig)

[JohnRoberts]

I have a roughly 100' tall tree in my back yard that was killed by lightning sometime in the last couple years. I am seriously tempted to take my chainsaw to it, but it is only about 15' from my property line and within striking distance of a nearby neighbor's (store) building.

I have had a few bad experiences with trying to get trees to fall where I want them to. They generally go where their center of mass pulls them. Some experienced woodsmen can walk trees around in almost any direction, but dead trees are a wild card as they can have unpredictable interior structures (and I am not a skilled tree cutter).

A few years ago I cut down an ugly dead tree in my neighbor's (now RIP) yard. He used to own and operate a logging company and refused to be within 50 yards of where I was cutting... he has seen how dead trees can misbehave when cut. I got that puppy down without too much drama but it was rotten and supported 3 different kinds of ants eating it from the inside.  An old pecan tree that fell in my yard last spring was likewise weakened by black carpenter ants.

But back to my lightning tree, no visible ants, but piles of bark falling off the very dead tree, probably boiled off by the lightning strike.  I tried to use trig  (tan theta) from the angle of the trunk's tilt to predict the center of mass and direction of fall. The tree doesn't have any major heavy limbs down low so trunk should dominate the tree's mass. Eyeballing the angle of the tilt with a level placed up against the trunk, I did some quick math last night and the center of mass computes to be 10' or more away from the trunk. That seems extremely unlikely for a still standing dead tree so I inspected it again this morning. 

Indeed the lower 20' of the trunk veers off at a 10-15' (degree) angle, but above about 20' it leans in the opposite direction moving the center mass back over the trunk, if not past it in the other direction.  I feel a little better now that it is unlikely to trash my neighbor's store when it falls, or gets dropped... He has his own 100' tall cottonwood in poor shape right next to his building to worry about. My similar aged cottonwood fell during Hurricane Katrina , luckily away from my house.  8)

The trig formula is tanget theta= opposite/adjacent. In my case the adjacent represents height of the tree, and opposite the distance from the trunk (roughly). So even taking the average height of the tree as 50', tan theta would be several feet away. But this ASSumes the tree trunk is a straight line, it isn't.

Geotropism encourages plants to grow up in opposition to gravity... Perhaps that tree got bent by Hurricane Katrina almost 15 years ago and then compensated growing straight up again? I lost about a half dozen trees from Katrina, a few in that part of my yard.  After it comes down, and it will come down one way or the other, I can inspect the tree rings to see if they grew fatter on one side opposite the lean to compensate, starting about 15 years ago. 

I attached a picture of that back section of my yard immediately after Katrina with two nearby trees on the ground. The now dead lightning tree is the almost straight tree on the left... you can see it leaning  a little to the left but some 15 years of new upper growth jogged back in the other direction.

JR

 

[scott2000]

First thought that came to my mind was a comealong or something..... But I'm not a tree guy..... Have gotten lucky in the past with ropes and pulling while cutting..... but It was scary.... and too chaotic for comfort imo....

 

[JohnRoberts]

First thought that came to my mind was a comealong or something..... But I'm not a tree guy..... Have gotten lucky in the past with ropes and pulling while cutting..... but It was scary.... and too chaotic for comfort imo....

I thought about that and for a roughly 100' tall tree the attachment point would have to be set pretty high up or the tree could still fall in the wrong direction.

I am feeling lucky after eyeballing it for center of mass to guess direction, but I can wait for it to fall. It won't stand forever. If it falls by itself it won't obviously be my fault.  And there are two smaller trees between it and the store building that might take some of the weight, if it falls the wrong way.
===
I attached a picture of the old pecan tree that fell in my yard during a storm last year. Even though already down, some of the large branches were sticking up high enough to involve power pole lines running parallel to the street if not controlled. I anchored them with ropes before cutting and it helped somewhat. I was pretty lucky with that tree missing my phone line on one side, and power lines on both sides, falling conveniently in the middle. It bumped my house power feed wire (visible in the picture) on the way down but didn't drop it.  8) 

When Katrina dropped my big Cottonwood, it took out my power pole and transformer with it.   

JR

PS: In hindsight trigonometry didn't really help, but it still was interesting.

 

[scott2000]

wow....I never knew they were that big.......

 

[boji]

I got to that part of youtube some night ago that had a compilation of all the tree fells gone wrong.  It certainly doesn't look like an exact science, not without being able to estimate density with (I imagine) some ultrasonic or x-ray device. 

Course, all the pro's had safety lines around the sections they were cutting, but even then, it required coordination of the guy on the tree and the one adjusting tension on the rope to get it to control-fall in the desired direction.  It all looks dangerous to me.

 

[PRR]

A hundred feet? Near property?? Don't be crazy.

I had an 80' Pine by my driveway starting to pull out by the roots after a windstorm. It had nowhere to fall, densely surrounded by 50'-70' Spruce. I've lodged trees in other trees and it gets insanely dangerous. And those Spruce had been a liability: every year one fell across the drive or on the power line.

I started back away from property and felled about 23 large Spruce, to make a place to fell the large Pine. I have learned not to trust my judgement of lean and CG, trees fall in unexpected directions. I roped-up. Ladder to get a harness 20 feet above the cut. 3:1 tackle to a 1-ton comealong. Snug-up and take the front wedge out. Honk the rigging: 4,000-5,000 pounds force against a tree will counter significant lean. Take the back-cut. Many fell right on the rigging (went where I suggested) but quite a few went astray.

Even with rigging and practice, I did not want to touch the larger Pine. It looked like it would fall safe, but it could go very wrong, into the power line or smack the garage. I called Billy, a very experienced arborist. Experience is the key. It often took most of a day for me to rig-up and drop a Spruce. He put four wedges in back-cut and steered that big Pine right where he wanted it. He agreed it sometimes goes very wrong.

 

[PRR]

> I can wait for it to fall.

In most states, treefall is covered by the loser's Homeowner Insurance. If the neighbor has not put you On Notice that your tree looks dangerous, you can just let it fall and his insurance will pick-up (after deductible). If he does put you On Notice, you should mitigate. Your homeowner's insurance may agree to pay for an insured  arborist rather than wait for a claim on his building.

This is in-line with very old common law. (He enjoyed the shade for decades, he can take the lumps.) Some states have quite different laws. You really should let your insurance agent see the situation and advise you. Yes you might do the deed with $1 of gasoline and a beer, or you might crush a building and go to court. Insurance agents are experienced with finding the path of least friction.

 

[dmp]

Trees usually fall in the direction they are leaning. And a 100' tree will fall 100'    ;D
No trig needed.

Seriously though, we've had some trees brought down in difficult areas and they do them with bucket trucks.  We had an old pine with blister rust taken down and they brought in a 80' bucket truck.

People with a lot of skill can make trees fall away from the direction they are leaning by cutting a hinge and pounding in wedges to push it in the direction you want. I doubt any pro would do that anymore since the savings over a bucket truck isn't worth the risk of it going wrong.

 

[JohnRoberts]

> I can wait for it to fall.

In most states, treefall is covered by the loser's Homeowner Insurance. If the neighbor has not put you On Notice that your tree looks dangerous, you can just let it fall and his insurance will pick-up (after deductible). If he does put you On Notice, you should mitigate. Your homeowner's insurance may agree to pay for an insured  arborist rather than wait for a claim on his building.

This is in-line with very old common law. (He enjoyed the shade for decades, he can take the lumps.) Some states have quite different laws. You really should let your insurance agent see the situation and advise you. Yes you might do the deed with $1 of gasoline and a beer, or you might crush a building and go to court. Insurance agents are experienced with finding the path of least friction.

Speaking of big pines...  I have ten big-uns on my property that dwarf the power lines they tower above.

That is an interesting angle to approach the insurance company... I have been hoping to get the power company interested, they routinely take out trees that expose their lines to risk. If my pines don't qualify I don't know what does, but no luck yet. They took down a tree from my property (with my permission) about 15-20 years ago, in the same general area but a hardwood tree on the corner, not one of those pines.

Those pines survived the full force of Hurricane Katrina and only dropped off a few weak branches. That same storm took a half dozen trees from my property and left some other trees permanently leaning, in different directions because the eye came right over me, so wind changed direction before and after the eye passed.  I think those pines have some natural protection in one direction from the line of them in a row. In the other direction I am near the bottom of the hill, but I repeat this didn't help a number of my trees that went down.

The big, old pecan tree that fell last year had the trunk weakened by carpenter ants, and was unusually heavy with a bumper crop of unripe pecans. It wasn't much of a storm, probably the weight of pecans and wet leaves. I wish that tree had waited until the end of the season to fall... thousands of good looking pecans that never ripened. My pecan trees still standing don't have that kind of production.

In the picture you can see one old pine leaning, and I have little question about what direction it will fall.  8) I could probably steer it with a line to miss my house but it could reach across my front yard and even into traffic on the road out front. I need to get professionals to top these biguns.

The pines are closer to my red neck neighbor's house than mine, and he would probably sue me in a mSec. (He accused me of voting for Hillary because that is the worst insult he can imagine.  : ).

Before Hurricane Katrina local logging companies would advertise in the shopper newspapers that they harvest pines off private property for free, and I have a few truckloads of pine here easy, but those days are long gone.  They have the big dog equipment that can top the trees and take them down relatively safely, but the closeness to power lines is a wild card that would likely lead to higher prices from commercial guys, and probably hiring a power company rep to oversee the work.

I need to get the power company interested, they have a preferred tree services  (Asplundh). But I need to get a highly placed power company guy who owes me a favor. I have one friendly kid I used to play basketball with who has been climbing the utility lines maintenance ranks for several years now but still working outdoors on poles. He did fall off one and break his back a year ago, but still working outside.  If I cold call Asplundh I can hear cash register bells ringing in the background. I need to get the power company to want to help.

I could hire some local tree monkey to cut the trees (they're crazy enough). I saw one guy take down a neighbors similar sized dead pine that was hit by lightning a decade ago... he didn't kill himself doing it but I was uncomfortable just watching him, climb up the dead tree and take it down in sections while still sitting up on it.  The professionals have bucket trucks and other serious machines. My stand of ten is borderline enough wood, more than a days work, but I know it wouldn't be free... They probably need a day just to move the heavy equipment. There are probably another ten old pines on the end of my other neighbors property we could clear at the same time to help offset the overhead.

If this becomes a pay me now or pay me later situation, I don't know that sooner will be much cheaper than later. It would be more certain and the right thing to do.  :-[

JR

 

[JohnRoberts]

Trees usually fall in the direction they are leaning. And a 100' tree will fall 100'    ;D
No trig needed.

as often in the brewery the answer doesn't agree with the question.

Seriously though, we've had some trees brought down in difficult areas and they do them with bucket trucks.  We had an old pine with blister rust taken down and they brought in a 80' bucket truck.

I've seen some serious logging operations and they use machines that will clamp around the tree trunk down near the base, hold it and lift it up onto a truck (obviously very heavy machines). They also use cranes when topping tall ones. These machines are too big and heavy for my yard and would barely fit in my side street. 

People with a lot of skill can make trees fall away from the direction they are leaning by cutting a hinge and pounding in wedges to push it in the direction you want. I doubt any pro would do that anymore since the savings over a bucket truck isn't worth the risk of it going wrong.

I didn't realize it was that easy.  8) 

JR

 

[dmp]

The difficult part of that method (I've been told, never tried it myself) is the hinge can break and the tree will go the wrong way before you can get the wedge in. So you need to get the wedge in before cutting over to the hinge. So you need to plunge cut into the tree.

 

[PRR]

Asplundh  won't talk to mere people, they only contract big jobs like utilities.

Yes, wedging a tree is easy in drawings. Altho a 100' tree will need more than mere wedges; there are hydraulic jacks for big/heavy trees.

Yes, the "hinge" DOES break wrong. I got lazy on one small tree, had it roped to the west on one rope, started the back-cut of the hinge, it broke to the north and hung on my utility line. I got lazy because it was no bigger than my leg and I didn't apply tons of pull. Not only do you need a strong suggestion, I started double-roping in a Vee to discourage side-fall.

_MY_ Pines mostly do not give trouble. Not like the Spruce which try to root in thin soil and blow over by the roots. This Pine was the exception because it was right on the driveway and decades of oil and UPS trucks had compacted the roots, and the driveway fill is not very cohesive. We had a near-hurricane, wet and windy, and there were huge cracks in the driveway. The tree was going to blow down, but didn't get to it before that storm faded. But it had a good start on the next storm. So I wanted it out. It looked like it would go away from power and drive, but I have seen tree roots lift on one side, and then it rocks-back and falls the opposite way.

I have an injured Spruce by my garage, rot set in. But these weeds grow in clumps, I have three not even 5 feet apart, all leaning different ways. Not sure what I want to do there. Right now it would just damage a corner of the garage. But they grow a foot a year. In another decade it will total the garage, which could be the answer.

 

[JohnRoberts]

Asplundh  won't talk to mere people, they only contract big jobs like utilities.

They answered the phone when I called their local office sometime last year, but I don't recall being encouraged or getting a call back. I know they work for the power company, a lot.

I have cut down a decent number of trees over the decades and only the minority fell exactly where I wanted them to.

Oddly the dead tree that scared my neighbor (who operated a logging company when younger) came down without drama, but I was alert and on guard for funny business.

Yes, if we don't pay attention those trees keep getting bigger.  I planted about a half dozen fruit trees over the last two years but will be dead before they become problems for anybody.

JR

Yes, wedging a tree is easy in drawings. Altho a 100' tree will need more than mere wedges; there are hydraulic jacks for big/heavy trees.

Yes, the "hinge" DOES break wrong. I got lazy on one small tree, had it roped to the west on one rope, started the back-cut of the hinge, it broke to the north and hung on my utility line. I got lazy because it was no bigger than my leg and I didn't apply tons of pull. Not only do you need a strong suggestion, I started double-roping in a Vee to discourage side-fall.

_MY_ Pines mostly do not give trouble. Not like the Spruce which try to root in thin soil and blow over by the roots. This Pine was the exception because it was right on the driveway and decades of oil and UPS trucks had compacted the roots, and the driveway fill is not very cohesive. We had a near-hurricane, wet and windy, and there were huge cracks in the driveway. The tree was going to blow down, but didn't get to it before that storm faded. But it had a good start on the next storm. So I wanted it out. It looked like it would go away from power and drive, but I have seen tree roots lift on one side, and then it rocks-back and falls the opposite way.

I have an injured Spruce by my garage, rot set in. But these weeds grow in clumps, I have three not even 5 feet apart, all leaning different ways. Not sure what I want to do there. Right now it would just damage a corner of the garage. But they grow a foot a year. In another decade it will total the garage, which could be the answer.

 

[JohnRoberts]

I may have stumbled upon a useful connection. A guy working on his new/old dump truck parked in the empty corner lot next to my property says that he trims trees and has an 80' bucket truck. When I asked him about working around power lines he said he also worked as a line man.

Between me and my neighbor, we have a few truckloads of pine, and enough other onesy-twosey tree work to justify his time and effort. I need to point out my 20+ year old car.... to keep his prices low.

Judging by the condition of his new/old dump truck*** he may be hungry, but he is driving a nice late model pickup truck himself so may be smart enough to not kill himself in my yard.

JR

*** I actually went over to tell him that after he worked on it the other day and drove away, his dump truck tail lights were still on all night.... He figured that out from the dead battery, but has issues with the dump truck's brakes. I observed from driving without a fan belt the other day (another story), that fully functional brakes can be useful in traffic.  8)