Natural Resources
Conservation Service
Ecological site F005XB105CA
Douglas-fir-tanoak/huckleberry oak,
mountain slopes,
serpentinite and peridotite, clay loam
Accessed: 08/17/2026
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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
F005XB104CA Jeffery pine/huckleberry oak, mountain slopes, serpentinite and peridotite, clay loam
This site is often found in conjunction with F005XB104CA.
Table 1. Dominant plant species
Tree (1) Pseudotsuga menziesii
(2) Lithocarpus densiflorusShrub (1) Quercus vacciniifolia
Herbaceous Not specified
Physiographic features
This ecological site is found on the eastern margins of Mill and Rock creeks. It occurs on mountain slopes and ridges, which are strongly sloping to very steep.
Table 2. Representative physiographic features
Landforms (1) Mountain slope
Flooding frequency None Ponding frequency None Elevation 512 – 2520 ft Slope 9 – 50 % Water table depth 60 – 0 in Aspect Aspect is not a significant factor Climatic features
The climate has warm summers, and cool, moist winters. Coastal influence limits the diurnal range in temperatures. Inland summertime temperatures may range from 60 to 80 degrees F. The total annual precipitation ranges from 90 to 120 inches and usually falls from October to May.
*Precipitation and temperature data not available near ecological site.Table 3 Representative climatic features
Frost-free period (average) 180 days Freeze-free period (average) 180 days Precipitation total (average) 120 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
">Influencing water features
There are no unique hydrological features on this site.
Soil features
These well-drained, very deep soils developed from colluvium and residuum derived from serpentinite, periodite, and serpentinized peridotite of the Klamath terrain. They are neutral to moderately acidic at 40 inches with a dominantly loamy subsurface rock content ranging from very gravelly to extremely gravelly.
These sites have been tentatively correlated to the following soil map units and components within Redwood National and State Parks:
Map Unit Component
761 WalnettTable 4. Representative soil features
Surface texture (1) Very stony loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderately slow to moderate Soil depth 60 – 0 in Surface fragment cover <=3" Not specified Surface fragment cover >3" 10 – 30 % Available water capacity
(0-40in)2 – 6 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 – 6.6 Subsurface fragment volume <=3"
(Depth not specified)30 – 75 % Subsurface fragment volume >3"
(Depth not specified)5 – 13 % Ecological dynamics
Serpentine environments are largely influenced by the chemical composition of the underlying parent material. High amounts of magnesium and iron, coupled with low amounts of calcium, low nutrient availability, and other related environmental factors create distinct plant communities (Kruckberg, 1984). Plant growth and productivity are often limited by high heat and low water availability on these sites (Jimerson, 1994).
The fire regime and fire return intervals for serpentine soils are not well documented (Frost, 2000). Fires were likely of variable intensity and frequency. The potential for a stand-replacing fire is moderate on these sites due to moderate overstory cover and continuous shrub cover on most sites (Jimerson, 1995).
Douglas-fir (Pseudotsuga menziesii) is sensitive to fire when young, but when mature, it has developed a thick bark that is more resistant to low to mid-severity fire (Agree, 1993). Partial stand-replacement fires may occur on this site and lead to variable survival of Douglas-fir (Jimerson, 1995). Following severe fire, knobcone pine (Pinus attenuate) may dominate early seral stages (Jimerson, 1995). Huckleberry oak (Quercus vacciniifolia) is quite flammable and acts to carry fire to the crowns of trees (Howard, 2006).
Huckleberry oak, Pacific rhododendron (Rhododendron macrophyllum) and other shrubs respond to cutting or fire by sprouting, though they are also capable of reproducing via seed. Manzanita seed is stored in the soil and germinates following a disturbance from fire or site preparation (Adams, 1992). Pacific rhododendron is thought to be adapted to nutrient deficient sites by a mychorrizal relationship that assists in nutrient uptake (Hemstrom, et al, 1987).
State and transition model
Custom diagramStandard diagram
Figure 3. Douglas-fir-tanoak-huckleberry oak 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/tanoak/Huckleberry oakCommunity 1.1
Douglas-fir/tanoak/Huckleberry oakPlant Community 1. The presumed historic climax plant community (HCPC) is a mature multi-storied plant community dominated by Douglas-fir (Pseudotsuga menziesii) and tanoak (Lithocarpus densiflorus) with an occasional Jeffrey pine (Pinus jeffreyi) and western white pine (Pinus monticola). The overstory canopy cover is sparse to moderate. Conifer canopy cover increases on side slopes and in draws.
The shrub layer is moderate to very dense, and is dominated by huckleberry oak (Quercus vacciniifolia) and Pacific rhododendron (Rhododendron macrophyllum). Other shrubs that are present in varying amounts are California buckthorn, also know as California coffeeberry (Frangula californica), greenleaf manzanita (Arctostaphylos patula), pinemat manzanita (Arctostaphylos nevadensis), red huckleberry (Vaccinium parvifolium), California huckleberry (Vaccinium ovatum), and dwarf tanoak. The sparse forb layer is dominated by California fescue (Festuca californica) and Beargrass (Nolina or Xerophyllum).
1a) A moderate fire, or block harvesting Douglas-fir followed by burning would result in much of the overstory being removed or killed. The shrubs and hardwoods would respond by sprouting. Stored manzanita seed in the soil would germinate, thus increasing the overall shrub cover. See PC#2.
1b) A severe stand-replacing fire could lead to an infill of knobcone pine if a seed source is present. The tanoak and evergreen shrubs would sprout. Manzanita seed stored in the soil, would readily germinate, though it would be reduced somewhat by the fire's consumption of litter, (Adams, et al, 1992). See PC#4.
1c) Infrequent moderate-intensity fires would maintain PC#1.
*The serpentine plant community is extremely diverse and complex. This ecological site description has been generalized to reflect the Soil Order Level 3 mapping that took place. For more detailed plant association descriptions, see "A Field Guide to Serpentine Plant Associations and Sensitive Plants in North Western California", US Forest Service publication R5-ECOL-TP-006, 1995.*
State 2
Huckleberry oak/manzanita spp/tanoak/California buckthornCommunity 2.1
Huckleberry oak/manzanita spp/tanoak/California buckthornPlant Community 2. A shrub and hardwood-dominated plant community develops following a moderately severe stand-replacing fire or timber harvesting and burning. A huckleberry oak/manzanita shrub layer predominates. Tanoak sprouts vigorously following cutting or fire. Shrubs present include whiteleaf (Arctostaphylos manzanita) and pinemat manzanita, California buckthorn, red huckleberry, California huckleberry and Pacific rhododendron. Many of the evergreen shrubs reproduce both vegetatively and by seed. Whiteleaf manzanita does not sprout and reproduces only by seed (Howard, 1992).
2a) If is seed source is present, a knobcone pine plant community could establish following a severe fire. Evergreen shrubs and tanoak re-sprout, and manzanita will germinate from seeds stored in the soil. See PC#4.
2b) With fire exclusion, tanoak sprouts dominate the shrub layer, along with whiteleaf and greenleaf manzanita, California buckthorn, red huckleberry and California huckleberry. Gradual infill of Douglas-fir may occur in openings from adjacent seed sources. See PC#3.
2c) With repeated fire, the shrub community could be perpetuated. If the fire was exceptionally severe and conifer seed sources greatly diminished, infill could be delayed for a long period of time.
State 3
Douglas-fir/huckleberry oak/tanoak/manzanita spp./California buckthornCommunity 3.1
Douglas-fir/huckleberry oak/tanoak/manzanita spp./California buckthornPlant Community 3. The evergreen shrub and hardwood plant community may dominate the site for a long period of time; however, with fire exclusion, infill of Douglas-fir will slowly take place.
3a) With continued fire exclusion, Douglas-fir saplings continue to infill. The plant community slowly develops a sparse Douglas-fir canopy over a shrub layer of tanoak, huckleberry oak, whiteleaf and greenleaf manzanita, California buckthorn and red and California huckleberry. See PC#4.
State 4
Knobcone pine/Hucklberry oak/manzanita spp.Community 4.1
Knobcone pine/Hucklberry oak/manzanita spp.Plant Community 4. Knobcone pine is a fire-dependent species with cones that open and disperse seed following severe fire. Knobcone pine forms the overstory with huckleberry oak, whiteleaf, greenleaf and pinemat manzanita, and California buckthorn in the understory.
4a) After many years of fire exclusion, knobcone pine will begin to senesce. Douglas-fir will continue to infill, and eventually over time, the plant community will be dominated by Douglas-fir. See PC#5.
4b) This plant community would only be maintained with severe fire.
State 5
Douglas-fir/Huckleberry oak/manzanita spp.Community 5.1
Douglas-fir/Huckleberry oak/manzanita spp.Plant Community 5. After many years of fire exclusion, a gradual infill of Douglas-fir into a dying knobcone community may create a moderate density multi-storied stand. Knobcone pine gradually dies out or becomes a very minor component. A huckleberry oak and manzanita shrub layer forms the understory. Infill of Douglas-fir is slow, but continuous.
5a) If a moderate to severe fire were to occur, the plant community could be returned to a shrub-dominated community. See PC#2.
5b If a seed source is present, a moderate to severe fire with stand-replacement will enable knobcone pine to re-established. See PC#4.
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
Studies are lacking with regard to the animal communities within serpentine environments. Kruckeburg briefly discusses three papers that deal with animals found in serpentine environments, including butterflies, pocket gophers and populations of salamanders (Kruckeburg, 1984).
Hydrological functions
These soils are well-drained. They are highly erosive (Kruckeburg, 1992) and easily degraded.
Hydrologic group--C.Recreational uses
Recreational use and development may be limited by steep slopes and the high amount of rock fragments found in the soils.
Wood products
Site productivity is generally low on these sites, and the erosive nature of the soils does not make them well suited for timber management.
Other products
Native Americans gathered plant materials for cultural purposes and likely hunted in these areas.
Other information
Serpentine sites provide habitats for small mammals and birds and contain a diversity of rare and sensitive plant species.
Supporting information
Other references
Hemstrom, Miles A, Logan, Shiela E., Pavlat, Warren, 1987. Plant association and management guide: Willamette National Forest. R-6-ECOL-257-B-86. Portland, OR. U.S. Department of Agriculture, Forest Service, Pacific Northwest Region. 312pp.
Jimerson, Thomas M., et al. 1995. A Field Guide to Serpentine Plant Associations And Sensitive Plants in Northwest California.
Kruckeburg, Arthur R., 1984. California Serpentines: Flora, Vegetation, Geology, Soils, and Management Problems. Univerity of California Press.
Kruckeburg, Arthur R., 1992. Plant life of western North American ultramafics. Pp. 31-73 in BA Roberts and J. Proctor (eds.), The ecology of areas with serpentinized rocks, a world view. Kluwer Academic Publishers, Boston, MA.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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