Tree Heights & Force of Fall
Trees represent large amounts of potential energy standing above the ground. When trees fall, the force with which they hit the ground surface is proportional to their height to the fifth power.
The link address is: http://warnell.forestry.uga.edu/service/library/index.php3?docID=407&docHistory%5B%5D=2&docHistory%5B%5D=413
