Natural Resources
Conservation Service
Ecological site F005XB103CA
Douglas-fir-canyon live oak/tanoak,
mountain slopes,
sandstone and mudstone, very gravelly loam
Accessed: 06/01/2026
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Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
Associated sites
F005XB101CA Douglas-fir/tanoak, mountain slopes, sandstone and mudstone, clay loam
F005XB101CA is often found in conjunction with this site.
F005XB102CA Douglas-fir-tanoak/tanoak, mountain slopes, sandstone and mudstone, very gravelly clay loam
F005XB102CA is often found in conjunction with this site.
Table 1. Dominant plant species
Tree (1) Pseudotsuga menziesii
(2) Quercus chrysolepisShrub (1) Lithocarpus densiflorus var. echinoides
Herbaceous Not specified
Physiographic features
This ecological site is found near the Beaver and Pine ridge areas. It occurs on uniform to slightly convex mountain slopes, which are steep to very steep.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
(2) Ridge
Flooding frequency None Ponding frequency None Elevation 164 – 4921 ft Slope 50 – 100 % Ponding depth 0 in Water table depth 60 – 0 in Aspect Aspect is not a significant factor Climatic features
The climate on this site is characterized by cold winters and hot, dry summers. The average annual precipitation ranges from 49 to 80 inches with most falling as rain from November to April.
Table 3 Representative climatic features
Frost-free period (average) 250 days Freeze-free period (average) 250 days Precipitation total (average) 80 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
">Influencing water features
There are no influencing hydrological features on this site.
Soil features
These well-drained soils developed from colluvium and residuum derived from sandstone and mudstone. They are strongly to very strongly acidic at 40 inches with a dominantly loamy subsurface rock content ranging from very gravelly to extremely gravelly. These soils are dominantly shallow to lithic contact.
The site is found on the following soil components:
465 OaksideTable 4. Representative soil features
Surface texture (1) Extremely gravelly loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderate to rapid Soil depth 10 – 20 in Surface fragment cover <=3" 25 – 75 % Surface fragment cover >3" 10 – 15 % Available water capacity
(0-40in)1 – 2 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)4.5 – 5.5 Subsurface fragment volume <=3"
(Depth not specified)35 – 70 % Subsurface fragment volume >3"
(Depth not specified)0 – 10 % Ecological dynamics
The fire regime is characterized as moderate severity with infrequent fires that are classified as partial stand replacement events (Jimerson, 1994). They may also include areas of low to high severity. Generally because of steep slopes and low stocking levels, the amount of fuels is reduced, thereby lessening fire severity.
Canyon live oak (Quercus chrysolepis) dominates the driest, steepest slopes. It commonly persists as a subordinate species on these sites when associated with Douglas-fir (Pseudotsuga menziesii) (Burns, 1990, Eyre, 1980). Canyon live oak may regenerate via acorn or through sprouting and will persist in the absence of fire (Termenstein, 1989).
Repeated fire or cutting leads to a dominance of canyon live oak over Douglas-fir on these sites. Conversion to live oak chaparral may occur with repeated burning (Eyre, 1980). With fire exclusion, the area will return to woodland. The fire regime may lead to a mosaic of both species. High severity fire favors the re-sprouting of canyon live oak, and low severity fire will allow for Douglas-fir to be maintained as part of the stand (Jimerson, 1996).
State and transition model
Custom diagramStandard diagram
Figure 3. Douglas-fir-canyon live oak-tanoak model
More interactive model formats are also available. View Interactive Models
More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 2 submodel, plant communities
State 3 submodel, plant communities
State 4 submodel, plant communities
State 5 submodel, plant communities
State 1
Douglas-fir/canyon live oak/tanoakCommunity 1.1
Douglas-fir/canyon live oak/tanoakPlant Community 1. The historic climax plant community (HCPC) is also the interpretive plant community. The community is dominated by Douglas-fir (Pseudotsuga menziesii) in the overstory, with canyon live oak (Quercus chrysolepis) and tanoak (Lithocarpus densiflorus) in the sub-canopy. Conifer canopy cover is almost equal to that of the canyon live oak. On some sites, other minor occurring trees species may include California laurel (Umbellularia californica) and Pacific madrone (Arbutus menziesii).
The shrub layer is dominated by the shrub forms of tanoak and canyon live oak along with poison oak (Toxicodendron diversilibum). The forb layer is sparse and may include an occasional western swordfern (Polystichum munitum), common whipplea (Whipplea modesta) and Iris spp.
1a) Most conifers could be removed or killed following a moderate fire or harvesting and post-harvest burning, along with partial stand replacement. Canyon live oak, tanoak, and other hardwood tree and shrub species present would sprout. On some sites burning could lead to competition from deerbrush (Ceanothus integerrimus) or whitethorn (Ceanothus incanus) (Jimerson, 1996). See PC#2.
1b) Continued partial cutting of Douglas-fir, along with the removal of a future seed source, could trend the plant community towards becoming a hardwood-dominated site. Fire could remove the Douglas-fir seed source, allowing for the dominance of hardwoods for a period of time. See PC#5.
Forest overstory.The overstory is dominated by Douglas-fir with canyon live oak and tanoak in the sub-canopy.
Forest understory. The understory is dominated by tanoak.
State 2
Tanoak/canyon live oak/California bay/Pacific madroneCommunity 2.1
Tanoak/canyon live oak/California bay/Pacific madronePlant Community 2. This shrub plant community is a result of a partial stand replacement fire or block harvesting followed by burning.
2a) The hardwood tree and shrub community could dominate the site for a long period of time, especially if a Douglas-fir seed source is lacking. Fire exclusion allows for infill of Douglas-fir over time. See PC#3.
2b) Tree planting and brush management may be possible on some sites, though seedling survival would be expected to low due to rocky soils and low available water. A plant community with Douglas-fir, canyon live oak and tanoak could eventually develop. See PC#4.
2c) If this shrub community were subjected to repeated periodic burning, it could be kept in PC#2 indefinitely.
2d) With fire exclusion and continued growth, the shrub community would eventually develop back into a woodland community. See PC#5.
State 3
Tanoak/Pacific madrone/Douglas-fir/canyon live oakCommunity 3.1
Tanoak/Pacific madrone/Douglas-fir/canyon live oakPlant Community 3. Initially hardwood tree sprouts would dominate the plant community. Tanoak and Pacific madrone sprouts grow much more rapidly than those of canyon live oak, and quickly form the overstory canopy. Gradually, over what may be a very long period of time, Douglas-fir will infill into the tanoak/Pacific madrone community from adjacent seed sources.
3a) Eventually, after many decades, patches of Douglas-fir will overtop the hardwoods. See PC#4.
3b) Fire could set the plant community back to a shrub-dominated site. See PC#2.
State 4
Douglas-fir/tanoak/canyon live oakCommunity 4.1
Douglas-fir/tanoak/canyon live oakPlant Community 4. Douglas-fir dominates the tree overstory layer, with tanoak and canyon live oak forming the sub-canopy. Initially, tanoak grows faster than canyon live oak, and dominates the sub-canopy layer.
4a) Over time, with fire exclusion, canyon live oak will continue to infill and become a more significant component of the sub-canopy. See PC#1.
4b) A severe partial stand replacement fire, though infrequent, would return this plant community to the shrub stage. See PC#2.
State 5
Canyon live oak/tanoakCommunity 5.1
Canyon live oak/tanoakPlant Community 5. The plant community is dominated by canyon live oak and tanoak in the canopy, with the shrub forms of canyon live oak, tanoak, and poison oak in the understory. Partial cutting of Douglas-fir, and the removal of a future seed source, coupled with the difficulty in tree planting and survival could leave this site hardwood-dominated for a very long period of time.
5a) In the event of continued fire exclusion, Douglas-fir may eventually infill from adjacent stands. See PC#1.
Additional community tables
Table 5. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 6. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 7. Community 3.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 8. Community 4.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 9. Community 5.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
This mixed stand of Douglas-fir, canyon live oak, and tanoak provides both food and cover for a variety of birds and animal species. Canyon live oak serves as a perching site for birds and provides shade and cover for mammals. Acorns of canyon live oak and tanoak are an important dietary component for many birds and mammals.
These sites are utilized by large mammals such as bear, mountain lion, and deer. Smaller mammals include squirrel, rabbit, woodrat, fox, skunk and mice.
Birds that might utilize the site include quail, pheasant, turkey, morning dove, jays, mountain chicadee, and a wide variety of woodpeckers.
Hydrological functions
These slopes are steep and prone to erosion. The soils are very well-drained.
Hydrologic Group--D
Refer to the Soil Survey Manuscript for further information.Recreational uses
These sites are unsuitable for recreational uses due to the high amount of surface rock, depth to bedrock and steep slopes.
Wood products
Douglas-fir is employed in residential structures and light commercial timber-frame construction. It is also used for solid-timber heavy-duty construction such as pilings, wharfs, bridge components and warehouse construction.
Canyon live oak has some limited commercial use for furniture, pallets, multi-colored paneling and veneers. It is also used as firewood.
Pacific madrone is not widely used for wood products. It is utilized occasionally for flooring, cabinet making, and veneers. It is widely utilized as firewood.
Other information
Site productivity interpretations are based on the following site index curves:
Species Curve Base age
Douglas-fir 790 100 yearsTable 10. Representative site productivity
Common name Symbol Site index low Site index high CMAI low CMAI high Age of CMAI Site index curve code Site index curve basis Citation Douglas-fir PSME 80 84 58 63 – – – Supporting information
Inventory data references
Forestry data was collected at soil pedons and along transects in the CA605 soil survey. Pedon# Forest plot# 03-075 03035p 09F092 03-0734 09F101 no pedon 09F094 no pedon 09F096
Type locality
Location 1: Humboldt County, CA Township/Range/Section T7N R3E S14 UTM zone N UTM northing 4538257 UTM easting 433125 General legal description USGS Quadrangle Lord Ellis Summit Other references
Burns, Russell M., and Honkala, Barabara H., 1990. Silvics of North America. Volume 2. U.S. Department of Agriculture, Forest Service. Agricultural Handbook 654.
Jimerson, Thomas, et al, 1996. A Field Guide to the Tanoak and the Douglas-fir Plant Associations in Northwest California. U.S. Department of Agriculture, Forest Service. R5-ECOL-TP-009.
Laudenslayer, W.F. and Mayer, K.E., (Eds)1988. A Guide to Wildlife Habitats of California. California Department of Forestry and Fire Protection.
Terminstein, D., 1989. Quercus chyrysolepis. In: Fire Effects Information System [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [2006, May 1].Contributors
Judy Welles
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
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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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:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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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:
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Perennial plant reproductive capability:
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