Ecological site group EX044AESG03
Frigid, Udic, Loamy, Foothills and Drainageways (Western Hemlock - Western Redcedar Cool Moist Herb) Tsuga heterophylla / Clintonia uniflora , Tsuga heterophylla / Asarum caudatum
Last updated: 07/23/2020
Accessed: 12/22/2024
Ecological site group description
Key Characteristics
None specified
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.
Physiography
Physiographic Features
This ecological site group occurs mainly on forested glaciated hill or mountain back slopes, foot slopes and toe slopes. It is found between 785 feet and 5,590 feet in elevation on northwest to southeast aspects. Slopes generally range from 15 to 40 percent, but can be found on slopes up to 80 percent.
Landscapes: Mountains, Foothills, Valleys
Landform: Mountain slopes, Hill slopes, Outwash terraces, Lake Terraces, Escarpments, Flood plains
Elevation
Total range: 240 – 1,705m
(785to 5,590 feet)
Central tendency: 780-1155m
(2,560 to 3,790 feet)
Slope (percent):
Total range: 0-80
Central tendency: 15-40
Water Table Depth:
46 to >200 cm
(18 to >80 inches)
Flooding:
Frequency: None
Duration: None
Ponding:
Depth (inches): 0
Frequency: none Duration: None
Aspect:
Range: 235-20-170
Central tendency: 275-20-85
Climate
Climatic Features
During the spring and summer, a circulation of air around a high-pressure center brings a prevailing westerly and northwesterly flow of comparatively dry, cool and stable air into the region. As the air moves inland, it becomes warmer and drier which results in a dry season beginning in the late spring and reaching a peak in mid-summer. In the fall and winter, a circulation of air around two pressure centers over the ocean brings a prevailing southwesterly and westerly flow of air into the Pacific Northwest. This air from over the ocean is moist and near the temperature of the water. Condensation occurs as the air moves inland over the cooler land and rises along the windward slopes of the mountains or highlands. This results in a wet season beginning in October, reaching a peak in winter, then gradually decreasing in the spring.
Temperature
The pattern of average annual temperatures indicates the effect both of latitude and altitude. In general, it can be said that monthly means are 32° F or lower at stations above 5,000 feet from November through March; between 4,000 and 5,000 feet, November through February; 3,000 to 4,000 feet, December through February; and 2,000 to 3,000 feet, only one or two months. The diurnal range of temperature is, of course, most extreme in high valleys and in the semiarid plains. The magnitude of diurnal range varies with the season, being lowest in winter when cloudiness is much more prevalent, and greatest in the warmer part of the year. In summer, periods of extreme heat extending beyond a week are quite rare, and the same can be said of periods of extremely low temperatures in winter. In both cases the normal progress of weather systems across the region usually results in a change at rather frequent intervals.
Precipitation
To a large extent the source of moisture for precipitation regionally is the Pacific Ocean. In summer there are some exceptions to this when moisture-laden air is brought in from the south at high levels to produce thunderstorm activity. Seasonal distribution of precipitation shows a very marked pattern of winter maximum and midsummer minimum.
Snowfall
Snowfall distribution is affected both by availability of moisture and by elevation. Annual snowfall totals have reached nearly 500 inches. The major mountain ranges accumulate a deep snow cover during the winter months, and the release of water from the melting snowpack in late spring is a primary source of instream flows.
(from WRCC: Climate of Idaho)
Mean Annual precipitation
Total Range: 350-1420 mm
(14 to 56 inches)
Central tendency: 670-965 mm
(26 to 38 inches)
MAAT
Total Range 3.1-9.5 C
(38 to 49 F)
Central tendency: 5.6-7.2 C
(42 to 45 F)
Frost free period (days)
Total range: 80-135
Central tendency: 100-115
Climate Stations:
WA: GERMOME, NORTHPORT, SULLIVAN LAKE RS
ID: BENTON DAM, BENTON SPRING, BISMARK RS, BONNERS FERRY 1 SW, BONNERS FERRY BRG, CABINET GORGE, CLARK FORK 1 ENE, PORTHILL, PRIEST RIVER, PRIEST RIVER 2, PRIEST RIVER EXP STN, SANDPOINT KSPT, SANDPOINT EXP STN
Soil features
Representative Soil Features
This ecological site group is associated with several soil components. The soil components can be grouped into ten most common soil great groups: Udivitrands, Haploxerepts, Eutrudepts, Dystryudepts, Dystroxerepts, Hapludalfs, Fragixeralfs, Dystrochrepts, Dystrudepts, and Udifluvents.. Soils in this ecologic site are very deep to moderately deep with available water holding capacities mostly equal to or greater than 6.7 cm (in 100cm). Most of these soils have developed in till, outwash colluvium and residuum from various rock types that has strong influence from Mazama tephra. The soils are mostly well-drained or moderately well drained. Surface textures are dominantly ashy silt loam, or ashy loam.
Soil series occurring in this ES group:
Ahren, Aits, Bane, Berray, Bonner, Bouldercreek, Boundary, Brodeer, Cabinet, Caribouridge, Courvash, Crash, Dewberry, Dodgecreek, Elmira variant, Fernline, Frycanyon, Garveson, Glaciercreek, Hartill, Highfalls, Hubub, Huckle, Hugus, Hun, Ibex, Jaypeak, Jeru, Keeler, Klootch, Kruse variant, Leadpoint, Mission, Moscow, Moso, Myrtlecreek, Noxlin, Ojibway, Pearsoncreek, Pend Oreille, Porthill, Priestlake, Rathdrum, Redlock, Rubson, Smackout, Smackout variant, Stevie, Tamarack, Threemile, Typic Udifluvents, Vassar, Vay, Waits, Zee, Zioncreek.
Parent Materials:
Kind: Volcanic ash, Till, Outwash, alluvium, Residuum, and Colluvium
Origin: Granite, Metamorphics, and Metasedimentary rock
Surface Texture: (<2mm fraction)
(1)Ashy Silt Loam
(2)Ashy Loam
Subsurface Texture Groups: Loamy, Sandy
Surface Fragments
Vegetation dynamics
Ecological Dynamics of the Site
This site occurs most commonly on north slopes, cool benches, and dissected drainages in Northern Idaho and NE Washington. The bulk of this site occurs in The Selkirk Mts. LRU in Northern Idaho and extends west to the NE corner of Washington. The depth of volcanic ash in the soil along with high precipitation makes this site highly productive. It is recognized by USFS Forest Habitat Types of Northern Idaho as the Western hemlock / Queenscup bead lily and Western hemlock / Wild Ginger habitat types. The WH/beadlilly habitat type is the most prolific and occurs on all aspects. The wild ginger type occurs on moister landscapes, usually on toe slopes or drainage areas. The cooler portions of this site occur at higher elevation lack western redcedar and have rusty menziesia as key shrub indicator.
This site has the highest ecological dynamics depending on type and degree of disturbance, and tree species seed source. Western hemlock and western redcedar will eventually dominate the overstory without major fire disturbance. Grand fir, Douglas-fir, western white pine, and western larch could be present in varying amounts. Understory reproduction and 2nd level overstory will be dominated by western hemlock and western redcedar due to their high degree of shade tolerance. There will be a large component of downed wood caused by windthow, seral species die-out, and insect and disease mortality. Paper birch is a key deciduous tree species in this hemlock-cedar ecological site. It can be a prominent understory component in early to mature stands and eventually dies out in the late climax forest.
Fire frequency in these stands occurs in long intervals of 150+ years. Due to the large volume of wood, stand replacing fires were the norm leaving the site naturally reforested by western white pine. After the white pine blister rust epidemic western larch, Douglas-fir, and in drier areas ponderosa pine gets established depending on seed source and competing shrub species. Grand fir, western hemlock, and western redcedar will also reestablish on the site through time. Lodgepole pine can be present and prevalent on sites after fire.
Ceanothus, alder species, and Douglas maple can reestablish quickly on these burnt sites slowing down natural reforestation. Reoccurring severe fires causing soil degradation can keep the site in a shrub dominated condition for long periods. Western larch is not as hardy as western white pine in competing with the brush species through natural regeneration. Larch needs to immediately establish on bare soil without much competition. The loss of the dominant white pine component again has caused a higher occurrence of Douglas-fir, grand fir, western hemlock, and western redcedar in developing stands.
The understory vegetation can be very rich in areas receiving enough sunlight. Key species include Queenscup bead lily, hooker fairybells, starry Solomon seal, wintergreen, huckleberry spp., and sword fern.
Major Land Resource Area
MLRA 044A
Northern Rocky Mountain Valleys
Subclasses
- F044AY504WA–Frigid, Udic, Loamy Foothills and Drainageways, high water table (Western Hemlock/Moist Forbes) Tsuga heterophylla / Clintonia uniflora , Tsuga heterophylla / Asarum caudatum
- F044AY505WA–Frigid, Udic, Sandy Hill slopes and Outwash terraces (Western Hemlock/Moist Forbes) Tsuga heterophylla / Clintonia uniflora , Tsuga heterophylla / Asarum caudatum
Stage
Provisional
Contributors
Gary Kuhn
Click on box and path labels to scroll to the respective text.