Salix jepsonii Shrubland Alliance
Jepson willow thickets
Jepson willow thickets
USDA Ecological Section Map
Summary Information
- Primary Life FormShrub
- Elevation1000-3400 m
- State RarityS3
- Global RarityG3
- DistributionUSA: CA, NV, OR (TJM2)
- Endemic to CaliforniaNo
- Endemic to California Floristic Province and DesertsNo
- Date Added2009/09/01
Characteristic Species
Salix jepsonii is dominant or co-dominant in the shrub canopy with Acer glabrum, Alnus incana ssp. tenuifolia, Cornus sericea, Lonicera conjugialis, Lonicera involucrata, Paxistima myrsinites, Rhododendron columbianum, Rhododendron occidentale, Ribes montigenum, Ribes nevadense, Rubus parviflorus, Salix geyeriana, Salix lemmonii, Salix lucida ssp. lasiandra, Sambucus racemosa and Spiraea splendens. Emergent trees may be present at low cover, including Abies concolor, Abies magnifica or Pinus contorta ssp. murrayana.
Vegetation Layers
Shrubs < 3 m; canopy is open to continuous. Herbaceous layer is variable.
Membership Rules
- Salix jepsonii > 5% absolute cover in the shrub canopy or > 50% relative cover in the shrub canopy (Potter 2005).
Habitats
Stream banks and flood plains within moderate to very narrow canyons. Soils are alluvium, usually derived from granitic parent materials. The USFWS Wetland Inventory (1996 national list) recognizes Salix jepsonii as an OBL plant.
Other Habitat, Alliance and Community Groupings
| MCV (1995) | Montane wetland shrub habitat, Subalpine wetland shrub habitat |
| NVCS (2009) | Salix jepsonii seasonally flooded shrubland alliance |
| Calveg | Willow (riparian scrub) |
| Holland | Montane riparian scrub |
| Munz | Not treated |
| WHR | Montane riparian |
| CDFW CA Code | 61.118.00 |
National Vegetation Classification Hierarchy
| Formation Class | Mesomorphic Tree Vegetation (Forest and Woodland) |
| Formation Subclass | Temperate Forest |
| Formation | Temperate Flooded and Swamp Forest |
| Division | Western North America Flooded and Swamp Forest |
| Macro Group | Western Cordilleran montane-boreal riparian scrub |
| Group | Western North American montane-subalpine riparian scrub |
Remarks
Salix jepsonii is a riparian shrub up to 3 m tall. Its leaves are bicolored, relatively hairless on top, and densely silky and hairy below. Shrubs produce large quantities of wind-dispersed seeds. Seeds are not dormant and remain viable for only a few days. They germinate rapidly on a moist soil. Plants will sprout from their root crown or stem base after fire or cutting.
This alliance occurs in the mid to high elevations of northern California mountains. They border steep bedrock or boulder-dominated streams subject to spring snowmelt flooding. Stands remain moist during the dry season from capillarity and subsurface flows. S. jepsonii typically dominates the shrub layer, but in many cases there is near equal cover of emergent conifer trees (Potter 2005); if Pinus contorta ssp. murrayana trees are > 10% cover, these stands belong in that alliance. Understory species composition is similar to the Senecio triangularis alliance. Potter (2005) considered this alliance most ecologically closely related to the Salix geyeriana alliance, which is widespread on the eastside of the Sierra Nevada, where S. jepsonii seldom grows.
This alliance occurs in the mid to high elevations of northern California mountains. They border steep bedrock or boulder-dominated streams subject to spring snowmelt flooding. Stands remain moist during the dry season from capillarity and subsurface flows. S. jepsonii typically dominates the shrub layer, but in many cases there is near equal cover of emergent conifer trees (Potter 2005); if Pinus contorta ssp. murrayana trees are > 10% cover, these stands belong in that alliance. Understory species composition is similar to the Senecio triangularis alliance. Potter (2005) considered this alliance most ecologically closely related to the Salix geyeriana alliance, which is widespread on the eastside of the Sierra Nevada, where S. jepsonii seldom grows.
Life History Traits of the Principal Species
| Salix jepsonii | |
|---|---|
| Life forms | Shrub; winter deciduous |
| Seed storage | Transient |
| Seed longevity | Short |
| Mode of dispersal | Water/hydrological; wind |
| Germination agents | None |
| Mode of sprouting | Buds on small branches; underground structures |
| Survivability after fire/disturbance | Fire-hardy; high sprouter |
| Disturbance-stimulated flowering | No |
| Reproductive range | 2 years to life of plant |
| Recruitment | Low to medium; episodic |
| Regional variation | Low |
Fire Characteristics
Fluvial processes primarily maintain the alliance rather than fire. Salix jepsonii sprouts rapidly from damage.
| Fire return interval | — |
| Seasonality | — |
| Size/extent | — |
| Complexity | — |
| Intensity | — |
| Severity | — |
| Type | — |
| Regional knowledge | — |
Regional Status
The range of Salix jepsonii includes the Southern Cascades (M261D).
- Klamath Mountains (M261Aq). Stands occur in ravines and north-facing hollows at montane elevations, such as at Manzanita Creek RNA (Taylor and Teare 1979a, see Cheng 2004).
- Sierra Nevada (M261Eh, Ek, Eo, Eq). Stands occur adjacent to upper montane forests throughout the western flank of this section, and a distinct break between this alliance and Salix geyeriana alliance occurs along the Sierra Nevada crest. Most inventories are from the central and southern subsections where elevation, stream size, stream gradients, and geomorphic setting differentiate associations (Potter 2005). Stands in these regions and at Snow Canyon RNA (Nachlinger 1992, see Cheng 2004) associate with stands including those of the Alnus incana, Cornus sericea, and the Salix orestera alliances. Adjacent upland stands include Abies magnifica, Pinus contorta, and Populus trichocarpa alliances.
Management Considerations
Salix jepsonii provides shade at stream banks and streams. It colonizes disturbed areas such as bars, and it provides rapid stabilization to such sites (Potter 2005).
Associations
- Salix jepsonii [1]
- Salix jepsonii - Cornus sericea [2]
- Salix jepsonii - Paxistima myrsinites [3]
- Salix jepsonii / Senecio triangularis [2], [4]
References
- [1] Nachlinger, J.L. 1992
- [2] Potter, D.A. 2005
- [3] Taylor, D.W.;Teare, K.A. 1979a
- [4] Ratchford, J.;Boul, R.;Keeler-Wolf ,T.;Evens, J. 2024b (in progress)
- Cheng, S. 2004