Red squirrel, Tamiasciurus hudsonicus

Fig. 275  Girdling of branches by red squirrel. Chewed surface of sapwood is smooth	Fig. 276  Squirrels often gnaw patches of bark near tree bases.	Fig. 277  Discoloured branch tips damaged during feeding.	Fig. 278  Damage to lateral shoots from activity in upper crown.

Distribution:  Throughout B.C. except for the Queen Charlotte Islands and the south coast mainland.  Attacks are concentrated in the central southern interior.

Tree Species Attacked: Damage is primarily on young lodgepole pines (between 6 to 20 cm dbh), but may also occur on western larch, ponderosa pine, western white pine, Douglas-fir, grand fir, and birch. 

Signs & Symptoms: Red squirrels cut or peel the lateral and terminal shoots, and remove or hollow out the buds. These are often found on the ground around affected trees. Vertical or diagonal strips of bark up to 1 cm wide are gnawed from the branches and main stem of saplings. Gnawed surfaces are relatively smooth and toothmarks are indistinct. Squirrels often feed on pine stem rust blisters and mistletoe infections. Short strips of bark may be found at the tree base as a result of crown girdling, and occasional dead tops may be visible. Most damage occurs in spring and early summer. Freshly cut cones and piles of cone scales on the ground indicate squirrel activity. Droppings are 8 mm in length, elliptical, and are found on logs and stumps where squirrels have been feeding. 

Damage: Tree growth is reduced due to feeding on the lateral or terminal buds. Scattered dead tops result from occasional girdling in the crown. Partial basal girdling of saplings can occur over extensive areas in some plantations, leading to reduced growth and scattered mortality. Squirrel populations fluctuate with the size of the spruce and Douglas-fir cone crop. Thus, damage may be more noticeable during some years than others.

Similar Damage: Crown girdling in larger trees may be confused with porcupine damage. Short strips of bark at the base of the tree can help to distinguish recent squirrel damage. Hare damage to sapwood is similar to squirrel damage; however, the gnawed appearance of the sapwood and the size of the trees attacked distinguished hare damage from squirrel damage.

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Contact Tim Ebata if you have comments on the presentation of this information.

BC Ministry of Forests
Forest Practices Branch
P.O. Box 9513 Stn. Prov. Gov.
Victoria, BC
V8W 9C2

Section phone: (250) 387-8739
Section fax: (250) 387-2136

Last updated March 04, 2002