Relation of Air and Bark Temperatures of Infested Ponderosa Pines During Subzero Weather

Abstract

Subcortical temperatures were recorded, during subzero weather, on Ponderosa pine trees infested by the western pine beetle {Dendroctonus brevicomis) in E. Oregon. Air temps. as low as [long dash]15[degree] F. resulted in important reductions of overwintering broods. Differences in subcortical temps. were found to be due principally to differences in bark thicknesses.