General information

Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.

MLRA notes

Major Land Resource Area (MLRA): 006X–Cascade Mountains, Eastern Slope

Stretching from northern Washington to southern Oregon, the Cascade Mountains, and spans the entirety of the mountain slopes, foothills, elevated plateaus and valleys on the eastern slopes of the Cascade mountains. This MLRA is a transitional area between the Cascade Mountains to the west and the lower lying Columbia Basalt Plateau to the east. Situated in the rain shadow of the Cascade Crest, this MLRA receives less precipitation than portions of the cascades further west and greater precipitation than the basalt plateaus to the east. Geologically, the majority of the MLRA is dominated by Miocene volcanic rocks while the northern portion is dominated by Pre-Cretaceaus metamorphic rocks and the southern portion is blanketed with a thick mantle of ash and pumice from Mount Mazama. The soils in the MLRA dominantly have a mesic, frigid, or cryic soil temperature regime, a xeric soil moisture regime, and mixed or glassy mineralogy. They generally are moderately deep to very deep, well drained, and loamy or ashy. Biologically, the MLRA is dominated by coniferous forest, large expanses of which are dominated by ponderosa pine, Douglas-fir or lodgepole pine. Areas experiencing cooler and moister conditions include grand fir, white fir, and western larch while the highest elevations include pacific silver fir, subalpine fir and whitebark pine. Economically, timber harvest and recreation are important land uses in these forests. Historically, many of these forests would have experienced relatively frequent, low and mixed severity fire favoring the development of mature forests dominated by ponderosa pine or Douglas-fir. In the southern pumice plateau forests, less frequent, higher severity fire was common and promoted the growth of large expanses of lodgepole pine forests.

LRU notes

This broad group of sites encompasses meadow and riparian sites that occur across the MLRA. These sites range across MLRA 6 and span broad gradients of plant community composition, physiography, geology, and climate. These sites share common influences of adjacent riparian areas or wetlands and moist to wet soils with udic or aquic soil moisture regimes.

Classification relationships

Riparian Zone Associations of the Deschutes, Ochoco, Fremont, and Winema National Forests (Kovalchik 1987):
HQS2-21 – POTR/SYAL/ELGL

Riparian And Wetland Vegetation of Central and Eastern Oregon (Crowe et al. 2004):
CEGL000609 – POTR/SYAL
This site concept describes an herbaceous layer with a greater component of sedges and a shrub layer with a greater cover of willow compared to these associations.

Ecological site concept

This site represents a riparian meadow occurring within the foothills of the eastside of the Oregon Cascades. The reference plant community is dominated by overstory aspen (Populus tremuloides), a shrub layer of willow (Salix spp.) and snowberry (Symphoricarpos spp.), and an herbaceous layer dominated by various sedge (Carex spp.) species. This site is like the common quaking aspen - snowberry community found throughout the Eastern Cascades, yet it experiences higher soil moisture and a higher water table allowing an increased component of species adapted to aquic conditions such as willow (Salix spp.) and sedge (Carex spp.) species. As such, this site likely experiences similar successional dynamics to aspen stands under these associated conditions. In comparison to other wet meadow sites described in the area, this site is drier and warmer and is not found occupying areas with coarse pumice soils. The soil moisture regime is xeric to aquic and the soil temperature regime is frigid.

This is a provisional ecological site and is subject to extensive review and revision before final approval. All data herein should be considered provisional and contingent upon field validation prior to use in conservation planning.

Associated sites

Similar sites

Table 1. Dominant plant species