. Vegetation of Oregon and Washington. Botany Oregon Ecology; Botany Washington (State) Ecology. Artemisia tridentata remains the dominant shrub. Soils associated with this association belong to the Brown or Solonetz great soils groups. Response of the Artemisia/Festuca community to fire or grazing is essentially the same as that of the Artemisia/Agropyron association. Agropyron spicatum-Festuca idahoensis Association Eventually a point is reached on transect where Artemisia tridentata drops from climax communities on zonal habitats (table 24). This leaves a monotonous herbaceous cover dominat
. Vegetation of Oregon and Washington. Botany Oregon Ecology; Botany Washington (State) Ecology. Artemisia tridentata remains the dominant shrub. Soils associated with this association belong to the Brown or Solonetz great soils groups. Response of the Artemisia/Festuca community to fire or grazing is essentially the same as that of the Artemisia/Agropyron association. Agropyron spicatum-Festuca idahoensis Association Eventually a point is reached on transect where Artemisia tridentata drops from climax communities on zonal habitats (table 24). This leaves a monotonous herbaceous cover dominated by perennial grasses (fig. 123). Again, this change indicates an improved moisture regime (Daubenmire 1966) and a third zone, the Agropyron spicatum-Festuca idahoensis Zone. The definitive Agropyron spicatum- Festuca idahoensis association is dominated by these two perennial grasses plus Poa se- cunda. There are few forbs; and Artemisia tri- dentata, A. tripartita, Symphoricarpos albus, and Rosa spp. do not occur in this association (table 24). Opuntia polyacantha may be a minor climax species south of the Snake River. The Agropyron-Festuca association oc- curs on a wide variety of soils, including those belonging to Brown, Chestnut, Chernozem, Piano sol, Solodized-Solonetz, and Prairie- Grumosol (intergraded) great soil groups. Fire has little effect on this community since neither of the dominants is seriously affected. As in the prior associations, Bromus tectorum is the main increaser with grazing. Festuca idahoensis/ Symphoricarpos albus Association The fourth and moistest of the steppe zones is the Festuca idahoensis/Symphoricar- pos albus Zone (fig. 124). Here, a whole group of species is added (table 24), produc- ing a luxurious meadow-steppe (Daubenmire 1966). This zone has as its climax the Festuca idahoensis/Symphoricarpos albus association. Figure 124. — The vegetational mosaic in the Festuca idahoensis/Symphoricarpos albus Zone includes herb-rich meadow steppe
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