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Biology & Damage

Porcupines are herbivores eating many plants, consuming the inner tree bark, twigs, and leaves with preferences for ponderosa pine, aspen, willow and cottonwood. However, practically all species of trees in their range are eaten. Porcupine damage to cottonwood trees along Montana's streams and rivers has at times been serious. In addition, porcupines produce significant damage to fruits, vegetables, corn, alfalfa and small grains. Damage to forest plantings, ornamental plants and orchards can be significant when a porkie gets started on them. Extensive girdling of trees in a given area often occurs when porcupines congregate around good winter denning sites.

Porcupines have a strong attraction to salt from sweat left on tool handles, canoe paddles, gloves, pack straps, horse harness, etc. The resins in plywood also have a great appeal for porcupines and they have been known to destroy siding on cabins, sheds, containers and signs. Car tires and even hoses have been attractive to porcupines supposedly for the mineral content.

Most porcupine damage occurs in winter when woody plants become the staple of the diet. Porcupines damage plants by girdling, basal gnawing, or branch clipping which often reduces tree