PREDICTION OF STAND SUSCEPTIBILITY TO FEEDING DAMAGE BY RED SQUIRRELSIN YOUNG LODGEPOLE PINE

This paper provides a forecast model to predict when and where signifi cant feeding damage by red squirrels (Tamiasciurus hudsonicus Erxleben ) will occur in managed stands of lodgepole pine (Pinus contorta Dougl . var. latifolia Engelm.). Information from 51 managed stands (average DBH >6.0 cm) in the interior of British Columbia and from past squirr el population studies was used to formulate the model. Incidence of da mage was significantly greater in stands originating from wildfire tha n from harvesting. Stands within the Montane Spruce biogeoclimatic zon e had the highest levels of damage of the five zones sampled. There wa s no relationship between damage incidence and average stand diameter, area of managed stand, or site class. In a subset of stands where und erstory shrub data were available, shrub cover was positively related to incidence of damage. Major factors in the forecast model that influ ence stand susceptibility include (i) stand origin and proximity to ma ture timber; (ii) frequency of cone crops leading to squirrel populati on increases in juvenile pine; and (iii) shrub cover, which may provid e security from predators. Additional potential factors include (iv) s witching of predators from squirrels to snowshoe hares (Lepus american us Erxleben) during peak years of the hare cycle and (v) fertilization . A decision-making profile is outlined for prespacing surveys to iden tify susceptible stands.