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Some characteristics of Douglas-fir trees and their immediate surroundings were assessed for their association with Douglas-fir beetle infestation in Kootenay Lake Forest District. Examination of trees in plots paired within 50 m revealed that a small crown and clumping of Douglas-fir trees were related to infestation for trees larger than 40 cm diameter at breast height (1.3 m). Relative probability of infestation between trees in plots within 50 meters can be calculated using live crown ratio and basal area occupied by Douglas-fir trees in a 0.01-ha range. Live crown ratio and average diameter of trees within a 0.01-ha plot around the tree were important. Carbon isotope ratio of wood samples from a 5-year period prior to infestation was significantly related to infestation status, possibly indicating moisture stress in infested trees previous to infestation.