Xylem Traumatic Resin Duct Formation in Response to Stem Fungal Inoculation in Douglas-Fir and Lodgepole Pine

Xylem traumatic resin ducts (TRDs) in Douglas-fir form response to mechanical injury, fire, and root pathogens, but it is unknown if these at the stem bark-beetle-associated fungi. Meanwhile, TRDs are rarely documented lodgepole pine. In southern Rocky Mountains, TRD formation two species from sterile (Control) fungal inoculation treatments (Aggressive, Weak (Douglas-fir only)) were compared; predicting following: (1) both trees would produce treatments; (2) Douglas-fir, Aggressive treatment promote denser larger than or Control (3) interspecifically, a higher density of pine treatments. Two months post-treatment, position indicated only induced on all had similar responses, except second line formed produced >7× more that twice size those Douglas-fir’s stronger indicates better resistance traits against bark beetle associate colonization. Understanding characteristics reaction specific damage can improve past disturbance reconstructions explain interspecific tree differences conducive resistance.