Natural Resources
Conservation Service
Ecological site F006XY706OR
Cryic Coniferous Flood Plain
Last updated: 9/11/2023
Accessed: 11/21/2024
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, Eastern Slope, 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 rainshadow 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
Related Plant associations:
Kovalchik 1987:
CEM211 - ENGELMANN SPRUCE/COMMON HORSETAIL-TWISTEDSTALK ASSOCIATION
Crowe et al. 2004:
CEGL000892 - Engelmann spruce/Mountain alder-Red-osier dogwood Association
Hopkins 1979:
CWM111 - White fir-Alder/Shrub meadow
Note: these associations may not be co-occurring but represent the range of potential plant communities represented by this site
Ecological site concept
This site represents a group of riparian communities dominated by an overstory of Engelmann spruce (Picea engelmanni) with mountain alder (Alnus incana) common. Botanically, shrub and herb species may be diverse and highly influenced by depth to water table, yet similar ecological dynamics drive ecosystem change. Present knowledge of these dynamics is incomplete for this site, but fire and alterations of adjacent stream channels will influence plant community composition, productivity and succession.
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
R006XB102OR |
Cold Wet Meadow Occupying adjacent low energy meadows rather than higher energy floodplains and low terraces along streams |
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Similar sites
R006XB102OR |
Cold Wet Meadow Occupying low energy meadows rather than higher energy floodplains and low terraces along streams |
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Table 1. Dominant plant species
Tree |
(1) Picea engelmannii |
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Shrub |
(1) Alnus incana |
Herbaceous |
Not specified |
Click on box and path labels to scroll to the respective text.
Ecosystem states
State 1 submodel, plant communities
P1.1A | - | Floodplain degradation, soil loss |
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P1.1B | - | Severe fire removing overstory canopy |
P1.2A | - | Extended time in the presence of sufficient sediment loads upstream and channel and vegetation structure that permits aggradation |
P1.3A | - | Time will allow Engelman spruce to recolonize the site |