Unlike other bark beetles, the fir engraver needs only to kill a strip of cambium near its gallery to successfully reproduce.  Because it does not necessarily kill the tree, fir engraver attacks result in a variety of tree symptoms: (1) dead branches, (2) top kill, and (3) complete tree mortality.  Trees that appear healthy are rarely killed except when they are affected by root disease or by a severe, temporary stress such as drought or defoliation. Fir engraver attacks that do not kill the tree cause scars clearly visible on the outer bark. 
     Various defects such as stain,

     Throughout most of its range FE has a one- year life cycle; two years may be required at high elevations, and during warmer years, a partial second generation may form.
     Adult FE are shiny black beetles about 1/5th inch long (4 mm).  Viewed from the side, they have an incurved

posterior with a small central bump that is more pronounced in the males (fig. 10). 
     There is no evidence of aggregation pheromones in FE.  The attack dynamics of this species can be explained solely by its sensitive primary attraction response to host volatiles.

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Forest Insect and Disease Identification and Management of Northern & Central Rocky Mountain Conifers and hardwoods