INSECT ENEMIES OF WESTERN FORESTS He) 
mercial stands of western Oregon and Washington seems to be quite 
resistant to bark-beetle attack, and serious damage is rarely found. 
At times, however, this tree suffers from bark beetles, even in this) 
region of favorable growth. In the eastern portion of the Douglas 
fir range, where growth conditions are less favorable and the timber 
is of inferior quality, bark-beetle outbreaks of disastrous proportions 
Ficurp 58.—Typical galleries and egg niches of Pityogenes fossifrons. 
are not an uncommon occurrence. The Douglas fir beetle (Dendroc- 
tonus pseudotsugae) is the most common offender and causes the 
bulk of the damage. Small Douglas firs are frequently killed by 
the fir engraver beetles, particularly in situations where large num- 
bers of these small beetles have developed in windfalls or slash. The 
engravers usually responsible for this type of damage are Scolytus 
unispinosus or Pseudohylesinus nebulosus. 
