[College of ACES] [University of Illinois] [Illinois CES]

sidewalk vs. roots

fcforester@aol.com
Fri, 21 Nov 1997 23:02:36 -0600

If it is true that a tree cannot exert a force against another object, such as a piece of kite string that will gurdle a tree, then why can a root exert enough force to displace a
200-lb sidewalk?

My theory is this: it is not the root that exerts the force, but the freezing and thawing of the ground that displaces the sidewalk. However, this theory meets contention if you consider this phenomenon occurs in tropical regions where there obviously is no thawing and freezing process.

What do you think???