Green Foliage Losses from Ponderosa Pines Induced by Abert Squirrels and Snowstorms: A Comparison

Author： Allred W. Sylvester Gaud William S.

Publisher： Society of American Foresters

ISSN： 0885-6095

Source： Western Journal of Applied Forestry, Vol.8, Iss.1, 1993-01, pp. : 16-18

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Abstract

Abert squirrels (Sciurus aberti) are obligate herbivores on ponderosa pine (Pinus ponderosa). The inner bark of pine shoots is considered one of the predominant food resources obtained by foraging squirrels. As squirrels forage for this resource they induce green needle losses from chosen feed trees. Amounts of induced green needle losses appear to vary according to the availability of alternative foods and squirrel population densities. Weather also induces green needle losses to ponderosa pines. Results of this study indicate that, at least in some years, heavy snowstorms can induce greater amounts of green needle losses than squirrels. Squirrel herbivory was not indicated as a factor in any tree mortality. However, losses due to snowstorms are more severe since they may cause the actual depletion of trees in the forest because of the tree mortality they inflict. West. J. Appl. For. 8(1):16-18.