Evaluation of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seed tree mortality on the Clearwater National Forest, ID

Effects of fire, root disease, and bark beetles on Douglas-fir (Pseudotsuga menziesii (Mirb.)Franco) seed trees were evaluated on the Powell Ranger District, Clearwater National Forest, Idaho.Thirty trees on an underburned and an unburned site were sampled for xylem water pressure potential, root disease infection, bark beetle infestation, and fine root biomass.Fire intensity was moderate to light.Bark beetle girdling and root disease infection by Armillaria obscura (Schaeff.:Secr)was higher on the burned site but not significantly (P>.22 and P>.12, respectively).Infection by Phaeolus schweinitzii (Fr.)Pat. was not significantly different between the two sites.Visual esti mates of stress were used as xylem water pressure potential results were not conclusive.The combined effects of fire damage, root disease infection, and bark beetle girdling caused stress and tree mortality.