Is there a specific term of art used in the log cutting industry (or
in engineering or phyics) to describe what a tree does as it falls
over after being cut, or for that matter any body that is "tipping
over"?  To clarify, it seems like the base of the tree is in fact not
falling at all, and even may move upwards a little bit.  The top part
of the tree does come crashing to the ground, but I was wondering if
there are specific words perhaps only known in the industry to
describe what is happening.  Engineering folks may have a word for
this process as well, thanks!

Dear meatscape-ga;

Thank you for getting back to me so quickly. Since you are agreeable
with the information I posted in the comments section as an answer, I
am merely reposting the information here in order to officially close
your question:

The term you are looking for is a "toppling" tree. The term is used by
the United States Geological Survey in its glossary of terms:

"...toppling of trees..." 
USGS
http://biology.usgs.gov/s+t/SNT/noframe/zy198.htm

"TOPPLE: To totter and fall. To lean over as if about to fall."
DICTIONARY.COM
http://dictionary.reference.com/search?q=topple

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have any questions about my research please post a clarification
request prior to rating the answer. Otherwise, I welcome your rating
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in the near future. Thank you for bringing your question to us.


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Good comments and answer, this was my first answered question

In lumberjack jargon the act of cutting a tree down and dropping it to
the ground is called ?felling?.

How?s that?

Tutuzdad-ga

close, I'm more looking for the word to describe what happens to the
tree AS it is felled, or to describe any physical object that is
"tipping over".  A scientific/engineering/lumberjack word for "tipping
over" will do

I found no such terminology in OSHA?s logging terminology glossary

OSHA
http://www.osha.gov/SLTC/etools/logging/glossary/glossary.html

Or in the industry standard safety manual:

SAFETY STANDARDS FOR LOGGING OPERATIONS
http://www.lni.wa.gov/wisha/rules/loggingoperations/default.htm
http://www.lni.wa.gov/wisha/rules/loggingoperations/HTML/54-2.htm#WAC296-54-539

At the risk of sounding sarcastic (which is not my intent) it appears
that a falling tree is simply called a ?falling tree?.

From of common language approach the concept seems to be much simplier
than scientific terminology. Having said that, perhaps the term you
are looking for is a "toppling" tree. This term is used by the United
States Geological Survey in it's glossary of terms:

"...toppling of trees..." 
USGS
http://biology.usgs.gov/s+t/SNT/noframe/zy198.htm

"TOPPLE: To totter and fall. To lean over as if about to fall."
DICTIONARY.COM
http://dictionary.reference.com/search?q=topple

How's that?

Tutuzdad-ga

how about kickback?

check out the animation, halfway down the page.

www.osha.gov/SLTC/etools/logging/manual/felling/cuts/dangers/dangers.html

Toppling works, that is probably as close as I will get.

Hello,

   You say in your original question, "...it seems like the base of
the tree is in fact not falling at all, and even may move upwards a
little bit." Is this *really* what you're interested in uderstanding?
If so, then although there are words for the destabilising of standing
objects (felling, toppling, etc.), they don't necessarily help yuu to
undertstand your observation about the upwards motion of the
tree-trunk near the cut point.

   What happens is that a trunk isn't cut clean through to topple the
tree. It's cut almost through, but a bit is left intact, called for
obvious reasons the "hinge", to constrain the falling tree's motion.
When the hinge is thin enough there's no longer enough support to hold
the tree upright and it tips over, rotating about the hinge. As long
as the hinge still connects the stump with the toppling portion, it'll
impose a centripetal force to keep the falling trunk's motion in a
sweeping circular path about the hinge.

   The falling portion of the tree has its own mass center. In the act
of falling the hinge quickly disintegrates and snaps apart. The mass
center of the whole freely falling tree proceeds to fall along a path
determined by its instantaneous velocity at the moment the hinge
breaks. But it was also rotating at that moment, and the falling trunk
is then free to rotate about its mass center, which is naturally well
away from the hinge. The top of the tree is already rotating such that
it is swinging towards the ground, so the other end necessarily swings
upwards.

In lumberjack jargon, a tree that hangs on at the base and ultimatly
splits upward along the grain during falling in the manner you
described is called a "Barber chair". However, this nickname doesn't
actually describe the falling tree, only the end result (a partially
cut stump with an unsevered portion that slightly resembles the back
of a chair).

tutuzdad-ga