I 



Good-to-fair vigor - Crowns are closed 

 at least in clumps; crown lengths are 

 greater than 50 percent in young 

 stands and greater than 33 percent in 

 older stands. Growth has not yet 

 slowed greatly. 



Fair-to-poor vigor - Crown ratios are 

 poor. Growth and mortality are 

 nearly balanced. 



Very poor vigor - Stands having very 

 poor vigor are generally in a decadent 

 condition due to insects, disease, 

 stagnation, suppression or old age. 

 Mortality is likely to exceed growth. 



Watershed 



The region or area drained by a river or other 

 body of water. 



Water yield 



The average annual runoff for a particular 

 watershed expressed in acre-feet. 



Water yield increase 



An increase in average annual runoff over 

 natural conditions due to forest canopy re- 

 moval. 



Windthrow 



A tree pushed over by wind. Windthrows 

 (blowdowns) are common among shallow 

 rooted species and in areas where cutting or 

 natural disturbances have reduced the density 

 of a stand so individual trees remain unpro- 

 tected from the force of the wind. 



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Glossary 



G-7 



