I'm sure some of you saw this on Cryptomundo and maybe else where but I have to wonder if this is physically possible for a bipedal animal to do.



I tried to find, online and unsuccessfully, the forces necessary to break off the trunk of an aspen tree with a diameter, at the break point, of 3-8 inches at 13 to 15 feet.

I honestly don't want to hear more stories of seeing the same thing because I've heard plenty, I just want to try and understand the physics behind such a feat.

This sounds like a good challenge for ozman.

Challenge accepted, but will take me a few days. In the meantime, I am reminded of the red cockeated woodpecker of the Carolina coast (ummmm, HUH?)


During one of the hurricanes in the ninties, all the pine tree that these birds used for nesting broke off at a uniform height -- it just happened to be the height where the birds had hollowed out the trunks for nesting. In one season the birds went from "common" to "endangered", and all these pines trees were broken off at a uniform height....north-south roads were closed by the broken trunks.


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I await the Ozman's verdict....I am thinking this would give us a rough estimation of the physical power a sas is able to generate. If they are any sightings in the area, we could possibly be able to extrapolate strength to size, etc blah blah...sorry, thinking out loud again.....

I'll just sit quietly in the corner then.

Don't suppose a picture would help?

Well, BD, you're right about the derth of directly related info regarding "forces required to fracture and seperate" specific to aspen. Aspen is considered a low-strength hardwood.

http://en.wikipedia.org/wiki/Aspen

However, here is the perpindicular force necessary to "rupture" (break) a pine board after it is lumber:
90 ~ 100 lbs /sq in of cross sectional area. That's barring any pre-existing damage or knots at the stress point. (w/ stress applied to the greater dimension)

So a kiln dried pine 2x4 should withstand up to about 720 pounds of force. And that sounds about right to me, having moved safes and pianos and car engines...of course, the "span", i.e., the length of the board, makes a huge difference.

For a critter w/ an armspan of 8 feet or more and reputed to have upper body strength similar to a gorilla, it seems plausible that a three inch trunk could be broken without grunting. But it would require some gymnastics. The ape would have to have one hand or foot at the fracture point and the other farther up the trunk, nearly equivelent distance to armspan.

Source:

http://www.engineersedge.com/lumber.htm

For 5" X 5" and larger it is 100 ~ 110 (2,500 lbs of force)


Mitigating factors:

There are several moths that feed on aspen and one that feeds ONLY on aspen.

http://en.wikipedia.org/wiki/List_of_Lepid...feed_on_poplars


What I have been unable to determine is whether the larvae of any of these moth species climb to a uniform height of 13 to 15 feet in the aspens. If they do, and if the predators that feed on those larvae (woodpeckers, primarily) then bore into the trees at that height, then the required forces are reduced substantially (perhaps as much as 1/2).


Boils down to being only a little better than purely guessing.

Thanks Bud, physics definitely isn't my strong suit. I imagine a "green" tree would be harder to break clean than a dry board. Am I mistaken in that assumption? Although this report doesn't state if the breaks were clean, twisted or ragged breaks I always wonder if these types of claims are physically possible, it sounds like it very well might be.

No, actually, the dead, kiln dried stuff is stronger than living, growing wood. Aspen, being a member of the willow family, tends to bend easily and even with breaks in the heart wood that leave the bark more or less intact do not necessarily kill the tree. It is through the bark that all the nutrients and waste is transported, so the tree can continue to live even after the trunk is broken. The "juices" also act as a lubricant that allows some movement of the trunk within the bark to minimize damage to the bark if the trunk moves / is displaced up to some critical angle. But, if completely severed, the dead, dried heartwood is harder and stronger than the living wood.

Experiment:

Try breaking a freshly cut, 1" diameter branch over your knee. Now try breaking a dried branch from the same tree and same diameter over your knee (ouch!!)