Every day, on our morning walk, the dogs and I pass a terrible tree of thorns.
It is a fearsome tree. From its trunk far up into its branches, it is bursting with clusters of two- and three-inch long razor-sharp thorns. If you tried to shinny up the tree, you’d be punctured in a hundred places before you got up into the branches. It’s the ultimate form of protection against an unwanted tree invasion.
The thorn defense is formidable, but why does it exist? I always understood thorns, and other biological and botanical defense mechanisms, to develop through the process of evolution and natural selection. For some reason, trees with thorns must have been better suited to surviving than trees that weren’t bristling with dagger-like projections — but why? Were there once bears in our sleepy suburban neighborhood, or other large, thick-furred mammals who were a threat to the tree and could only be discouraged by such long, sharp thorns? And what kind of threat did they pose that required such menacing defenses? Were they eating something the tree produced, or stripping its bark?
The thorn tree gives no answers. It just stands there, silent and dreadful, posing its thorny questions with no obvious answers in the vicinity.