Natural Resources
Conservation Service
Ecological site F003XY702OR
High Cascades Dry South Slopes
Accessed: 12/21/2024
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.
Figure 1. Mapped extent
Areas shown in blue indicate the maximum mapped extent of this ecological site. Other ecological sites likely occur within the highlighted areas. It is also possible for this ecological site to occur outside of highlighted areas if detailed soil survey has not been completed or recently updated.
Table 1. Dominant plant species
| Tree |
(1) Tsuga mertensiana |
|---|---|
| Shrub |
(1) Arctostaphylos patula |
| Herbaceous |
Not specified |
Physiographic features
This site is on moderately deep, steep, south facing, somewhat excessively drained soils on the sides of cindercones.
Table 2. Representative physiographic features
| Landforms |
(1)
Cinder cone
|
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 4,500 – 6,500 ft |
| Slope | 90% |
| Water table depth | 60 in |
| Aspect | SE, S, SW |
Climatic features
Winters are long, cold, windy and snowy, due to the very high elevations. Summers are short and cool. Effective precipitation comes mostly as snow. Average annual ppt is 67 inches.
Table 3. Representative climatic features
| Frost-free period (average) | 45 days |
|---|---|
| Freeze-free period (average) | 90 days |
| Precipitation total (average) | 100 in |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Influencing water features
None
Soil features
This site is found on steep, south facing slopes on cinder cones.
Table 4. Representative soil features
| Surface texture |
(1) Very gravelly sandy loam |
|---|---|
| Family particle size |
(1) Loamy |
| Drainage class | Somewhat excessively drained to excessively drained |
| Permeability class | Moderate to moderately rapid |
| Soil depth | 20 – 40 in |
| Surface fragment cover <=3" | 10 – 35% |
| Surface fragment cover >3" | 5% |
| Available water capacity (0-40in) |
2.8 – 5.1 in |
| Calcium carbonate equivalent (0-40in) |
Not specified |
| Electrical conductivity (0-40in) |
Not specified |
| Sodium adsorption ratio (0-40in) |
Not specified |
| Soil reaction (1:1 water) (0-40in) |
5.6 – 6 |
| Subsurface fragment volume <=3" (Depth not specified) |
20 – 55% |
| Subsurface fragment volume >3" (Depth not specified) |
5% |
Ecological dynamics
The historic climax plant community is dominated by Mountain hemlock. The site is harsh and droughty. The steep south facing slope receives direct solar radiation. That plus the dry cindery soil affects the type and amount of vegetation.
The tree cover is sparse but the shrub/grass/carex cover is high. Plant species that are drought hardy will survive on this site.
Fire has frequented this site. The cinder cone is a target for lightning strikes.
State and transition model
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Ecosystem states
State 1 submodel, plant communities
State 2 submodel, plant communities
State 1
Mountain hemlock plant community
Community 1.1
Mountain hemlock plant community
The Mountain hemlock plant community is the historic climax plant community. This site is much drier than others, due to the south facing slope. Overstory canopy cover is low. Understory vegetation cover is moderate to high. Drought hardy species prosper.
Forest overstory. The typical forest overstory of the Mountain hemlock plant community.
Forest understory. The typical annual production of the understory species to a height of 4.5 feet (excluding boles of trees) under low, high, and representative canopy covers.
The percentages expressed are pecent canopy cover. Those species with "0" percent have a canopy cover of less than 1 percent.
Table 5. Ground cover
| Tree foliar cover | 20-30% |
|---|---|
| Shrub/vine/liana foliar cover | 40-50% |
| Grass/grasslike foliar cover | 10-15% |
| Forb foliar cover | 0% |
| Non-vascular plants | 0% |
| Biological crusts | 0% |
| Litter | 5-10% |
| Surface fragments >0.25" and <=3" | 10-20% |
| Surface fragments >3" | 5-10% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 10-20% |
Table 6. Soil surface cover
| Tree basal cover | 0% |
|---|---|
| Shrub/vine/liana basal cover | 1-2% |
| Grass/grasslike basal cover | 1-2% |
| Forb basal cover | 0% |
| Non-vascular plants | 0% |
| Biological crusts | 0% |
| Litter | 10-15% |
| Surface fragments >0.25" and <=3" | 20-25% |
| Surface fragments >3" | 5-10% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 20-30% |
Table 7. Canopy structure (% cover)
| Height Above Ground (ft) | Tree | Shrub/Vine | Grass/ Grasslike |
Forb |
|---|---|---|---|---|
| <0.5 | – | 1-2% | 1-3% | – |
| >0.5 <= 1 | – | 5-10% | 10-15% | – |
| >1 <= 2 | – | 5-10% | – | – |
| >2 <= 4.5 | – | 25-30% | – | – |
| >4.5 <= 13 | 0-1% | 3-6% | – | – |
| >13 <= 40 | 30-35% | – | – | – |
| >40 <= 80 | 1-5% | – | – | – |
| >80 <= 120 | – | – | – | – |
| >120 | – | – | – | – |
State 2
Lodgepole pine
Community 2.1
Lodgepole pine
This plant community occurs quite frequently, due to frequent fires. Lodgepole pine established after a severe fire. At maturity mountain hemlock will move into the stand. White bark pine may be found, mostly at the highest elevation on the cones.
Forest overstory. The typical overstory composition of the Lodgepole pine plant community.
Forest understory. The typical forest understory composition of the Lodgepole pine plant community. Vegetation is described below 4.5 feet.
A value of "0" indicates a canopy cover of less than 1 percent.
Table 8. Ground cover
| Tree foliar cover | 15-20% |
|---|---|
| Shrub/vine/liana foliar cover | 30-40% |
| Grass/grasslike foliar cover | 10-15% |
| Forb foliar cover | 0% |
| Non-vascular plants | 0% |
| Biological crusts | 0% |
| Litter | 1-5% |
| Surface fragments >0.25" and <=3" | 25-30% |
| Surface fragments >3" | 10-15% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 10-15% |
Table 9. Soil surface cover
| Tree basal cover | 0% |
|---|---|
| Shrub/vine/liana basal cover | 5-10% |
| Grass/grasslike basal cover | 7-10% |
| Forb basal cover | 0% |
| Non-vascular plants | 0% |
| Biological crusts | 0% |
| Litter | 1-5% |
| Surface fragments >0.25" and <=3" | 25-30% |
| Surface fragments >3" | 10-15% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 20-30% |
Table 10. Canopy structure (% cover)
| Height Above Ground (ft) | Tree | Shrub/Vine | Grass/ Grasslike |
Forb |
|---|---|---|---|---|
| <0.5 | – | 1-3% | 1-2% | – |
| >0.5 <= 1 | – | 5-8% | 10-15% | – |
| >1 <= 2 | – | 10-15% | – | – |
| >2 <= 4.5 | – | 20-25% | – | – |
| >4.5 <= 13 | 0-1% | 0-1% | – | – |
| >13 <= 40 | 20-25% | – | – | – |
| >40 <= 80 | 0-1% | – | – | – |
| >80 <= 120 | – | – | – | – |
| >120 | – | – | – | – |
Additional community tables
Interpretations
Supporting information
Contributors
C Ziegler
Rangeland health reference sheet
Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.
| Author(s)/participant(s) | |
|---|---|
| Contact for lead author | |
| Date | |
| Approved by | |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
-
Presence of water flow patterns:
-
Number and height of erosional pedestals or terracettes:
-
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
-
Number of gullies and erosion associated with gullies:
-
Extent of wind scoured, blowouts and/or depositional areas:
-
Amount of litter movement (describe size and distance expected to travel):
-
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
-
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
-
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
-
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
-
Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):
Dominant:
Sub-dominant:
Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
-
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
-
Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
-
Perennial plant reproductive capability:
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