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Bigfoot snapped a 24" diameter Oak Trunk

Drewbot

Philosopher
Drewbot
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Sep 13, 2007
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Physics experts unite and debunk this.

White oak tree, 24" at the base, 60' tall, a Bigfooter said that
a 700 pound Bigfoot running along a branch toward the tree trunk, 45' up the tree, at 20mph, could break the tree trunk at 2' from the ground.

Said something about moment of inertia. Claimed he was a physics professor and that he did the diagram.

I claimed that the tree is a stationary object and would not be at all damaged by the force of the impact.

I showed examples of cars destroyed by 8" diameter trees, and the Footers said that the collision didn't happen 45' up in the tree.

I would show quotes, but I think it is against the rules of the Bigfoot forum where this took place.

Would the above scenario in any way, break the tree trunk at 2' above the ground?
 
The modern shape-shifting kind, or the Native American Sasquatch kind? ;)

A cone shape held rigid at teh big end, and pushed at the small end, wouldn't it break somewhere where the leverage exceeds the strength, not necessarily at the bottom. I suspect the roots will come out of the ground first. But:

The trunk alone would weigh 3500 pounds. Add on the momentum of the branches twigs leaves. And would be quite flexible up 45'. Add the air resistance to getting the upper footage of the tree flexing over far enough to break the base and welll ummm... no. And I suspect Biggie would get launched back the way he came from, also at 20 mph. Anybody got a Big gauge skeet gun handy?

On the other hand it is as ineluctable as "how many angels can dance on the head of a pin?", both being mythical creatures.
 
casebro said:
....

A cone shape held rigid at the big end, and pushed at the small end, wouldn't it break somewhere where the leverage exceeds the strength, not necessarily at the bottom.
Click to expand...

The leverage against the trunk increases arithmetically with the length, but the area sets the strength, and that increases at Pi R squared. I'd guess the trunk will break some where around 14.7 feet up. ;) But only if 700# @ 20 mph has enough energy.

We need a mechanical engineer to guesstimate this, as a final answer.
 
The trunks of lightening struck trees explode, probably from steam caused by the heat of all that electricity.

Any pics of that broken tree?
 
Drewbot said:
Physics experts unite and debunk this.

White oak tree, 24" at the base, 60' tall, a Bigfooter said that
a 700 pound Bigfoot running along a branch toward the tree trunk, 45' up the tree, at 20mph, could break the tree trunk at 2' from the ground.
Click to expand...

Nope. In energy terms, if you crash into the top of a tree you start putting energy into bending the tree. A charging Bigfoot has a decent amount of kinetic energy (here 25 kJ) but he's not the Incredible Hulk.

To displace the tree to a distance x you need to do work W = 1/2 k x^2 to overcome the tree's pushing back at you, with

k = (3*E*π r^4)/(2*L^3)

where r is the trunk radius, L is the length of the beam (here 45'), E is the elastic modulus of oak wood. I get k = 125000 newtons per meter. So if the entire kinetic energy of the charging bigfoot could be coupled into the tree's bending moment, Bigfoot could displace the tree top by about 50cm.

If you've ever been in a tree, you know that a 45' tree can bend by a whole lot more than 50cm before it snaps. A whole lot.

Your Bigfooter has been watching too many Marvel Comics movies.
 
Disclaimer: Bigfoot is dumb, and I am in no way arguing that an imaginary creature broke any tree, anywhere, at any point in history.

That said, as an ISA certified arborist, I have to say that trees break where they have weak spots. Point being, a given tree can snap very easily if there is an internal "flaw."

A broken tree in the forest (no matter where it failed) means less than nothing about anything.
 
Wait a minute, where in the holy hell did this footer claim to have seen a broken Quercus alba? I though 'squatches were (allegedly) indigenous to the PNW. White oaks are eastern trees.
 
ben m said:
If you've ever been in a tree, you know that a 45' tree can bend by a whole lot more than 50cm before it snaps. A whole lot.
Click to expand...

And (not that I understood that witchcraft with all of the numbers) this ^^^.
 
The bigfoot's energy wouldn't have been focused on a single point, so the weight would have been spread out over the tree trunk, reducing the amount of force on any one point.

Unless the Bigfoot was like my cousins and had a pointed head with the density of granite. In that case the tree wouldn't have had a chance.
 
Mr. Purple said:
Wait a minute, where in the holy hell did this footer claim to have seen a broken Quercus alba? I though 'squatches were (allegedly) indigenous to the PNW. White oaks are eastern trees.
Click to expand...
The claim is from Oklahoma.

Bigfoot is seen pretty much everywhere in America and Canada. He's bad. He's nationwide.
 
45' up a 60' Quercus Alba the 700 lb bigfoot can get up to 20mph running along a branch at that high up the tree. What the ****
 
Bigfoot climbs trees and knocks them down, bodychecking a tree trunk, just because he can. I understand now.
 
Mr. Purple said:
Wait a minute, where in the holy hell did this footer claim to have seen a broken Quercus alba? I though 'squatches were (allegedly) indigenous to the PNW. White oaks are eastern trees.
Click to expand...

To be fair, he actually saw the Bigfoot break the tree. And the tree was healthy by all appearances.
 
Can you ask him for me why he thinks the Bigfoot bodychecks trees? Does it lick the sap? Is it part of a mating display? I really honestly desperately need to know this information.
 
Knocking down trees as a territorial display to intimidate intruders/rivals
 
Drewbot said:
Would the above scenario in any way, break the tree trunk at 2' above the ground?
Click to expand...
Nope. 700 pounds at 20 miles per hour would be less force than a good strong wind and the weight of the oak's own branches. So for sure the impact theory is out.

But you asked, "in any way". So there is a possible scenario. If you get high enough in a tree to bend the top past a certain point where the weight of the tree adds to your weight, then it is possible to more slowly bend the top over to a point the trunk snaps. Pretty rare that low though. Generally you'd expect to see it snap much higher up.

I don't have numbers for you though. Just anecdotal evidence at a much smaller scale. My brothers and me used to actually try and snap trees as a game when we were young. Just climb up high enough and get an oscillation action going (bored kids living in a woods will make up all sorts of games) We managed to snap a couple, but not very many, and nothing larger than about 8 inches diameter. Only saw one break that low. If I remember correctly though, it was an oak and maybe 6 inch diameter tops. Shocked us though when it broke so low. Partly why we stopped that game.

I also once cut a tree, which fell into another tree top, bending it over to the ground. Then the tree I cut rolled off, freeing the other tree. It snapped up and back at me with such force, the trunk snapped on the rebound. This caused the second tree to fall directly at me. Damn near killed me. Missed by inches. That second tree that snapped was a good 2 feet diameter where it broke. Was a western cedar.
 
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