Three separate but parallel activities comprise the Forest Health Monitoring Program. In 

 detection monitoring, field crews measure selected biotic and abiotic features called indica- 

 tors of forest condition during a baseline period. These same features are then remeasured at 

 yearly or other intervals. Changes between the baseline and remeasurement conditions indi- 

 cate a response to natural forest change or ecosystem disturbance. The ecosystem indicators 

 are analogous to general blood pressure, pulse, and blood chemistry data recorded for people 

 in routine medical exams. Infant, juvenile, adult, and mature age groups have certain indica- 

 tor values for normal health. Values outside the normal ranges indicate something is amiss 

 and should be checked by a medical specialist. 



Evaluation monitoring begins when the cause of a significant and detected change is un- 

 known. Activities include intensive field sampling and combined interpretations by ecologists, 

 entomologists, hydrologists, pathologists, silviculturists, and others. These resource special- 

 ists are like the heart, kidney, lung, and other medical experts who are asked to diagnose 

 blood chemistry results that fall outside of normal values or that result from traumatic injury. 



Intensive site ecosystem monitoring combines knowledge from evaluation monitoring and 

 results from long-term watershed-scale research at a few sites with diverse forest types and 

 biomes typical of those found in the United States. The best example in the West is the H.J. 

 Andrews Experimental Forest near Blue River, Oregon, where forest research work has been 

 conducted since the 1940s. 



Combining information from all three monitoring activities allows predicting where and how 

 future ecosystem changes might take place under given environmental and management con- 

 ditions. 



lendix D- 



