When hiding in a tree den or under a rocky crevice, the porcupine is safe from attack. The porcupine also defends itself by climbing trees and positioning itself so that its quills are facing the fisher. This seldom works because the fisher is a terrific tree climber. It has specially designed claws and feet that make it an expert in tree climbing. It can climb down a tree with its face pointing downward and attack the porcupine from above.
Porcupines can damage trees in the forest because they eat and strip the bark.
The fisher has been introduced into some forests to control the porcupine population. Research has shown this approach to controlling porcupines works quite well.