Outbreaks of hemlock looper, an old-growth insect, 

 may increase on federal lands as harvesting de- 

 creases and more stands reach and exceed 100 

 years of age. 



An outbreak of hemlock looper was detected in 

 1 993 and 1 994 in western Washington. The 



population collapsed in I 99 5. source: cooperative Aenat 

 Survey.Washington Department of Natural Resources ar)d USDA Forest 

 Service. 



breaks can also occur in vigorous 80- to 100- 

 year-old stands. 



Today, the majority of stands that will sup- 

 port large hemlock looper populations are in 

 parks and reserves, mostly on federal lands in 

 northwest Washington. Those lands with 80- 

 to 100-year-old, vigorous western hemlock 

 stands or multistory older, predominantly ma- 



ture timber are susceptible to hemlock looper 

 outbreaks. 



The most recent defoliation from western 

 hemlock looper was found on the Mount 

 Baker-Snoqualmie National Forest. It was first 

 noticed during the 1992 aerial survey. The 

 outbreak peaked in 1993 with more than 

 49,000 acres defoliated. Populations collapsed 

 sometime between 1994 and 1995. In 1995, 

 extensive ground evaluations by forest health 

 specialists did not detect any live insects. 



True Fir 

 True fir stands continue to be changed 

 by an introduced insect — The balsam woolly 

 adelgid, an insect native to Europe, was first 

 noticed in the Pacific Northwest in the 1930s 

 on true firs in the Willamette Valley in Oregon. 

 It gradually spread to true firs in the moun- 

 tains. It slowly kills trees by infesting the twigs 

 and branches, or kills them quickly by infest- 

 ing the bole. It causes gouting (swelling) of 

 branches and sometimes of the trunk. Dam- 

 age and mortality are mostly confined to true 

 fir stands on federal lands, but it could spread 

 to all susceptible true fir stands. The Gifford 

 Pinchot, Mount Baker-Snoqualmie, and Olym- 

 pic National Forests report the highest mor- 

 tality associated with balsam woolly adelgid. 



Balsam Woolly Adelgid 



80,000 



60,000 



< 



"2 40 



000 



I 



20,000 



HiiiLiL 



Jl 



liU 



Year 



The number of acres with balsam woolly adelgid 

 damage in western Washington since 1969. Source: 



Cooperative Aerial Survey, Washington Department of Natural Resources 

 and USDA Forest Service. 



Washington — 50 



