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 are working within USDA and cooperating with other Federal land 

 managers to expand our knowledge. 



A few examples of the research conducted by the Forest Service clearly 

 demonstrate the different agency roles. For more than 3 decades. 

 Forest Service Research has conducted studies on the effects of air 

 pollution on trees and forests. Initially, this research focused on 

 the toxic effects of high concentrations of pollutants from point 

 sources. In general, these were local effects. Later, researchers 

 tackled the regional air pollution problem in southern California. 

 This research was instrumental in the finding that ozone is damaging 

 trees and forest ecosystems throughout the mountains of southern 

 California including the western Sierra Nevada into central 

 California. 



During the 1980' s, in response to concerns over "acid rain", Forest 

 Service Research greatly expanded efforts to study a broad range of 

 possible effects of air pollution on forests throughout the United 

 States. 



We recognize much of the research conducted under the National Acid 

 Precipitation Assessment Program (NAPAP) was not conclusive. Because 

 trees live for decades or centuries under normal conditions and often 

 respond in subtle ways to stresses such as air pollution, air 

 pollution research on forests takes time. This research is continuing 

 as a major component of our Global Change Research Program. 



