Grasses are adapted to constant grazing and are relieved that the young trees that threaten their existence are being polished off in the process. Many shrubs that would dearly love to grow taller than the grasses have developed dangerous thorns to protect themselves from the voracious beasts. Blackthorn is so vicious that its pointed protrusions persist on dead plants for years to impale rubber boots and even car tires, to say nothing of the hides and hooves of animals.
