How are the toothpicks like plant roots?
Remember the cracks made by the roots? When winter comes water will penetrate those cracks just like it did the road surface. The water will freeze, widening the cracks and breaking the rock. Spring’s thaw will carry particles away. Gusty winds hit the rock’s surface, picking up tiny particles. These particles blow about, not unlike a sandblaster, wearing down even more of the surface.
