Knowing the amount of herbage on rangeland is basic to management deci
sions related to livestock grazing. However, the amount of herbage ava
ilable for grazing changes seasonally. Therefore, changes in herbage b
iomass were examined in different communities of the fescue prairie. T
he study was conducted at 2 sites in southwestern Alberta. In the Porc
upine Hills near Stavely, changes in herbage biomass components were e
xamined in 3 communities: rough fescue (Festuca campestris Rydb.), Par
ry oat grass (Danthonia parryi Scribn.)-Kentucky bluegrass (Pea praten
sis L.), and Kentucky bluegrass-sedge (Carex spp.) by sampling at mont
hly intervals from April or May to late September. Observed trends amo
ng the rough fescue, Parry oat-grass-Kentucky bluegrass, and Kentucky
bluegrass-sedge communities were, for peak current year's standing pro
duction, 398, 305, and 226 g m(-2), respectively; for spring current y
ear's standing production as a percent of its peak, 73, 50, and 35%, r
espectively; and for percent losses of total herbage biomass, from fal
l to spring, 24, 43, and 56%, respectively. In the foothills near Pinc
her Creek, the standing crop of grasses and forbs was sampled using pa
ired subplots. One subplot was harvested in October and the other in A
pril. Dry matter losses over winter averaged 27 and 58% for grasses an
d forbs, respectively. Of the 3 communities examined, production on th
e rough fescue community was the greatest, least dependent on precipit
ation during the growing season, and least susceptible to weathering l
osses and, therefore, had the greatest forage values. The Kentucky blu
egrass-sedge community had the lowest forage values.