As a general rule, elk seem to like trees. But during the rut, when a bull becomes supercharged with testosterone levels 1,000-times higher than in spring and early summer, small trees and even clumps of grass beware. Along with sparring and wallowing, a bull will advertise his macho side to potential cows by “horning,” or rubbing the bark off an unsuspecting young tree. Thought to be more a display of dominance than territorial marking, horning acts as a warning to other bulls to keep their distance. Horning small trees with an antler or stick can be an excellent way to attract call-shy bulls.
But bulls aren’t a tree’s only enemy. Cows and calves have been known to annihilate whole aspen stands. Peeling away the bark with their teeth in winter or nipping fresh shoots every spring, elk love a good stand of aspen. Some aspens only a foot tall can have 50-year-old root systems, thanks to constant pruning by elk.