The aerial survey maps areas of mortality and defoliatior) in 

 Oregon and Washington forests each summer It is a cooper- 

 ative effort by the Forest Service and the two state 

 Forestry Departments. 



problems, such as bear damage in coastal Or- 

 egon forests. 



Survey results are used by Forest Service 

 and state resource managers to track the ap- 

 proximate location and acreage of dying or 

 damaged trees, to follow cycles of insect out- 

 breaks, and to predict future 

 damage. Land owners and man- 

 agers use survey results to locate 

 areas of insect or disease dam- 

 age on their lands and to aid 

 them in management decisions. 



Forest Inventory 



The Forest Service began to 

 inventory the timber resource on 

 federal, state, and private lands 

 in the 1930s. In 1993, the Na- 

 tional Forest Inventory in Oregon 

 and Washington was changed to 

 a multiresource survey, in which 

 understory vegetation, forest 

 floor woody material, wildlife 

 habitat, and damage agents are 

 also recorded. 



Forest inventories are ground- 

 based (rather than aerial); they 



now consist of a series of system- 

 atically located plots that are 

 remeasured periodically, at 8- to 

 10-year intervals. Data from the 

 plots are pooled to provide an es- 

 timate of forest condition across 

 any grouping, geographic or bio- 

 logical. 



Forest Heath Monitoring Plot 

 Networl< 



A network of forest health 

 monitoring plots has been estab- 

 lished on forested land of all 

 ownerships across the United 

 States. It consists of a series of 

 ground plots on which variables, 

 selected because scientists 

 thought they would be good in- 

 dicators of forest health, are 

 measured. Although some vari- 

 ables are the same as inventory 

 measurements, others are quite different, such 

 as tallying the number and diversity of lichens 

 as indicators of air quality. 



Forest Health Monitoring is a national program, 

 a partnership between several federal and state 

 agencies. The program was started in the North- 

 east in response to concerns about acid rain and 



Inventory crews visit permanent plots periodically to measure 

 and record a variety of attributes such as tree size, understory 

 vegetaiJon, woody material, and damage. 



Overview — 22 



