Yesterday we (the Oregon Department of Transportation) had to close a bunch of highways because of fallen trees. The wind and the ice combined with saturated soil made it a bad combination. Anyway, that reminded me of this deep philosophical question.
For the Gee Whiz file: At ODOT we have landscape crews who scour the roadsides looking for hazard trees, trees that could pose a threat to motorists traveling the highways. They identify the potential hazards and clear them out of the way. I love that name, hazard tree. Sounds like Ents on a rampage!