available for consumption under good management practices 

 is not used sufficiently, thus causing loss of forage. 



Undergrowth 



Collectively the shrubs, sprouts, seedling and sapling 

 trees, and all herbaceous plants in a forest. 



tlnderpopulation 



A size of population so low in number of individuals that 

 mortality is greater than in denser populations largely 

 because of increased exposure to unfavorable environmental 

 conditions. 



Undershrub 



A low shrub. 



Understocked 



Refers to a range area on which a smaller number of 

 livestock is present than it is capable of supporting ade- 

 quately for a given season, cf. Fully stocked. Overstocked. 



Understory 



Collectively the trees in a forest below the upper canopy 

 cover, cf. Overstory. 



Uneven-aged 



Refers to a forest in which considerable differences in 

 the ages of trees occur. 



Ungulate 



A Mammal with hooves, e.g., horse, cow, swine, elephant. 



Unicellular 



Refers to an organism that consists of only one cell, 

 e.g., blue-green algae, Protozoans. 



Union 



A homogeneous grouping of plant species within a given 

 stratum or of the same or closely similar life-forms, cf. 

 Synusia. 



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