Fraxinus latifolia Forest & Woodland Alliance
Oregon ash groves
Oregon ash groves
USDA Ecological Section Map
Summary Information
- Primary Life FormTree
- Elevation0-1700 m
- State RarityS3.2
- Global RarityG4
- DistributionCAN: BC. USA: CA, OR, WA (NatureServe) (USDA Plants)
- Endemic to CaliforniaNo
- Endemic to California Floristic Province and DesertsNo
- Date Added2009/09/01
Characteristic Species
Fraxinus latifolia is dominant or co-dominant in the tree canopy with Acer macrophyllum, Alnus rhombifolia, Calocedrus decurrens, Pinus ponderosa, Quercus kelloggii, Quercus wislizeni and Salix laevigata.
Vegetation Layers
Trees < 25 m; canopy is open to continuous. Shrub layer is sparse to intermittent. Herbaceous layer is variable.
Membership Rules
- Fraxinus latifolia > 5% absolute cover and > 30% relative cover in the tree canopy (Klein et al. 2007).
- Fraxinus latifolia > 5% absolute cover in the tree canopy (Potter 2005).
- Fraxinus latifolia > 50% relative cover in the tree canopy, or > 30% relative cover with Alnus rhombifolia or Umbellularia californica (Buck-Diaz et al. 2021).
- Fraxinus latifolia > 50% relative cover in the tree canopy, or > 30% relative cover with Acer negundo, Umbellularia californica, or Salix laevigata (Sikes et al. 2023).
Habitats
Riparian corridors, incised canyons, seeps, stream banks, terraces. Soils are alluvial. The USFWS Wetland Inventory (1996 national list) recognizes Fraxinus latifolia as a FACW plant.
Other Habitat, Alliance and Community Groupings
| MCV (1995) | White alder series |
| NVCS (2009) | Fraxinus latifolia temporarily flooded forest alliance |
| Calveg | Riparian mixed hardwood, White alder, Red alder |
| Holland | North Coast riparian forests, Great Valley mixed riparian forest, White alder riparian forest, Southern sycamore-alder riparian woodland |
| Munz | Foothill woodland |
| WHR | Montane riparian |
| CDFW CA Code | 61.960.00 |
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 | Vancouverian riparian deciduous forest |
Remarks
Fraxinus latifolia is a deciduous hardwood that attains a height of 25 m and an age of 250 years. Tree root systems are shallow. Plants produce large crops in 3- to 5-year intervals. Seeds are shed in the autumn and dis-persed by wind and water. Seedlings establish on moist soils rich in organic matter after the seeds have been cold scarified. Trees easily stump sprout (Owston 1990). South of the Kern River, F. latifolia is similar to Fraxinus velutina, suggesting hybridization between the two species (Munz and Laudermilk 1949).
In California, the alliance appears most commonly in the western Sierra Nevada, where it occurs adjacent to stands of the riparian Populus fremontii and Salix laevigata alliances or adjacent to stands of the upland Pinus ponderosa and Quercus chrysolepis alliances (Potter 2005). Larger, extensive, bottomlands stands occur in the North Coast Ranges from Sonoma County north; however, these have been poorly described. Otherwise, the alliance is scattered in riparian locations across northern California.
In California, the alliance appears most commonly in the western Sierra Nevada, where it occurs adjacent to stands of the riparian Populus fremontii and Salix laevigata alliances or adjacent to stands of the upland Pinus ponderosa and Quercus chrysolepis alliances (Potter 2005). Larger, extensive, bottomlands stands occur in the North Coast Ranges from Sonoma County north; however, these have been poorly described. Otherwise, the alliance is scattered in riparian locations across northern California.
Life History Traits of the Principal Species
| Fraxinus latifolia | |
|---|---|
| Life forms | Tree; winter deciduous |
| Seed storage | Soil |
| Seed longevity | Long |
| Mode of dispersal | Water/hydrological; wind |
| Germination agents | Inundation (moisture); stratification—winter |
| Mode of sprouting | Underground structures |
| Survivability after fire/disturbance | Fire-hardy; high sprouter (especially after flooding) |
| Disturbance-stimulated flowering | No? |
| Reproductive range | 30 years to life of plant |
| Recruitment | Medium to high |
| Regional variation | Low |
Fire Characteristics
Fluvial processes rather than fire primarily disturb the alliance. Plants sprout and easily establish by seed after disturbances including flooding (and sometimes fire). None of the many stands sampled by Potter (2005) had recent fire evidence. Potter (2005) suggests that small, fluvial patch disturbance is the norm, with stand-replacing events being unusual.
| Fire return interval | — |
| Seasonality | — |
| Size/extent | — |
| Complexity | — |
| Intensity | — |
| Severity | — |
| Type | — |
| Regional knowledge | — |
Regional Status
The range of Fraxinus latifolia includes the Klamath Mountains (M261A), Modoc Plateau (M261G), Northern California Coast (263A), and Northern California Interior Coast Ranges (M261C).
- Great Valley (262Aa, Ac-d, Af-i, Ak-m, Ao-p, Ar-s, Au). Planted stands occur at Suisun Marsh (Keeler-Wolf and Vaghti 2000). Stands in the Sacramento-San Joaquin River delta are rare (Hickson and Keeler-Wolf 2007). Vaghti and Greco (2007) describe F. latifolia as a component of several forest types.
- Northern California Coast (263Ag, Am). Stands occur in the Eel River, Russian River, and other drainages inland from the immediate coastal fog zone.
- Northern California Coast Ranges (M261Bb). Large stands occur along Outlet Creek just north of Willits and east of U.S. 101.
- Sierra Nevada (M261Eg, Ep, Eu). Stands occur mainly on stream banks and floodplains with Alnus rhombifolia and a variety of shrubs (Potter 2005, Klein et al. 2007).
- Sierra Nevada Foothills (M261Fa-d). Stands occur intermixed with A. rhombifolia, Populus fremontii, Quercus lobata, Salix laevigata, and other riparian woodland alliances throughout most of the foothills (Klein et al. 2007, Potter 2005). There is a tendency for more individuals in the southern foothills to have characteristics intermediate between F. latifolia and F. velutina.
- Southern Cascades (M261Dj). Stands occur at low-montane elevations with Cornus sericea (S. Smith 1998b).
Management Considerations
Fraxinus latifolia is well adapted to many flood regimes, though stands of the alliance usually occupy intermittently flooded locations (Potter 2005).
Associations
- Fraxinus latifolia [1], [2], [4], [6], [7]
- Fraxinus latifolia - Alnus rhombifolia [3], [4], [6], [7]
- Fraxinus latifolia / Cornus sericea [5]
- Fraxinus latifolia - Salix laevigata [8], [9]
References
- [1] Hickson, D.;Keeler-Wolf, T. 2007
- [2] Keeler-Wolf, T.;Vaghti, M. 2000
- [3] Klein, A.;Crawford, J.;Evens, J.;Keeler-Wolf, T.;Hickson, D. 2007
- [4] Potter, D.A. 2005
- [5] Smith, S. 1998b
- [6] Buck-Diaz, J.;Batiuk, S.;Evens, J.M. 2012
- [7] Klein, A.;Keeler-Wolf, T.;Evens, J. 2015
- [8] Ratchford, J.;Boul, R.;Keeler-Wolf, T.;Evens, J. 2023a (in progress)
- [9] Sikes, K.;Buck-Diaz, J.;Vu, S.:Evens, J. 2023
- Buck-Diaz, J.;Sikes, K.;Evens, J.M. 2021
- Owston, P.W. 1990
- Vaghti, M. ;Greco, S. 2007