Pollution from the Puget Sound region can be seen at Red Mountain, near Mount Adams, more than 

 70 miles away. Days with little or no pollution (left) contrast with high pollution days (right). 



All Species 

 Air pollution in Puget Sound has long- 

 range effects — ^The population of western 

 Washington is expected to increase in the fu- 

 ture and, with it, the air pollution caused by 

 automobiles and industries. Air pollution has 



What is a "hazard" tree? A hazard tree contains 

 some form of structural defect, a peculiar location, or a 

 combination of both, giving it a high possibility of failing 

 and causing injury to people or property. To be consid- 

 ered a hazard tree requires a valuable target — buildings, 

 cars, or people — close to the tree. A rotten tree deep in 

 the forest away from people is not a hazard because no 

 target has been identified, but a rotten tree near a camp- 

 site, road, or home is a hazard. 



many adverse effects on Northwest forests. 

 Ozone, a pollutant created from nitrogen ox- 

 ides and volatile organic compounds (both by- 

 products of automobile emissions) and sun- 

 light, damages a variety of plant species, with 

 symptoms ranging from leaf spotting to de- 

 creased growth to mortality. 

 Some plants, such as lichens, 

 are much more sensitive to 

 ozone than others and can be 

 used as ozone indicators. In 

 western Washington, the 

 number of lichen species, as 

 well as the concentration of 

 pollutants in lichen tissue, are 

 being monitored to identify 

 forested areas with ozone 

 damage. 



Decayed trees are haz- 

 ards in recreation sites — 

 Trees with root disease and 

 stem decays are potential haz- 

 ards in recreation sites, par- 

 ticularly in stands where the 

 trees are old. Homes being 

 built among the trees in the 

 urban-forest interface are at 

 particular risk from decayed 

 trees, which can fail without 

 warning, damage homes, and 

 injure or kill people. Efforts 

 are being made to teach 

 homeowners, landscape plan- 

 ners, highway department em- 

 ployees, park staff members. 



Washington — 46 



