Did the 1976-77 switch in the Pacific Decadal Oscillation make white spruce in the southwest Yukon more susceptible to spruce bark beetle?

Abstract

We applied dendrochronology to quantify the effects of climatic variation on white spruce radial growth in southwest Yukon, Canada. Local climate is cold and dry, thus tree growth was primarily limited by moisture, rather than temperature, although the mechanisms varied through time. Regionally, both temperature and precipitation increased in recent decades, in part due to the shift from the negative to positive phase of the Pacific Decadal Oscillation. Climate projections for this region include further increases in temperature and precipitation. Such changes may benefit white spruce growth and disturbance agents like the spruce bark beetle; however, specific impacts will depend on the seasonality and magnitude of climatic changes.