1 = High - species that persist for many years, under close grazing (to less than 2 inch leaf or stem length) and maintain themselves or increase under close grazing.  Species in this group best tolerate close grazing.  With the possible exception of blue grama, all species in this group produce more if not grazed closely.

2 = Medium  - species that persist for many years if 2 to 5 inches of stubble or regrowth are left at the end of each year (and each grazing period, for irrigated forage). 

3 = Low   - species sensitive to grazing pressure; 6 to 10 inches (depending upon the species) of stubble or regrowth must remain at the end of the year to assure continued high production and long stand of life.