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A3973 Celtis laevigata var. reticulata / Philadelphus lewisii Wet Scrub Alliance
Type Concept Sentence: This Celtis laevigata var. reticulata- and/or Philadelphus lewisii-dominated scrub woodland and shrubland alliance is found in the lower montane and foothill regions around the Columbia Basin, and north and east into the Central Rockies in Idaho and northwestern Wyoming where it occurs as numerous relatively small stands, dispersed and clustered in valley bottoms along riparian margins, on lower slopes of river terraces near seepage lines, and on scree slopes.
Common (Translated Scientific) Name: Netleaf Hackberry / Lewis'' Mock Orange Wet Scrub Alliance
Colloquial Name: Valley Bottom Netleaf Hackberry / Lewis'' Mock Orange Wet Scrub
Hierarchy Level: Alliance
Type Concept: The upper canopy of this scrub woodland and shrubland alliance is dominated by Celtis laevigata var. reticulata and/or Philadelphus lewisii, often forming dense thickets. Celtis laevigata var. reticulata occurs either as a short tree or tall shrub between 3-6 m in height. Philadelphus lewisii occurs as a tall shrub between 2-5 m in height. The short-shrub layer often contains Rosa woodsii, Rosa nutkana, or Sambucus nigra ssp. cerulea with other riparian shrubs such as Holodiscus discolor or occasionally Symphoricarpos albus and Toxicodendron rydbergii on moist sites. If present, the herbaceous layer may be dominated by the perennial bunchgrass Pseudoroegneria spicata. Poa secunda and Aristida purpurea var. longiseta are often present also. This alliance is found in the lower montane and foothill regions around the Columbia Basin, and north and east into the Central Rockies in Idaho and northwestern Wyoming, and south into canyons in the Colorado Plateau and in riparian areas in the southeastern Colorado plains. Stands occur as numerous relatively small stands, dispersed and clustered in valley bottoms along riparian margins, on lower slopes of river terraces near seepage lines, and on scree slopes. It can also occur in the active floodplain of intermittent streams and deep canyon bottoms of the Snake and Salmon rivers. Elevations range from 250-550 m in the Columbia Basin and 1400-1700 m in Colorado. Although sites are predominately on hot, dry southeastern to southwestern aspects, these trees access additional soil moisture that accumulates at the base of the colluvial slopes, or are riparian. Soils are poorly developed, well-drained alluvial or colluvial sands that often have a high percentage of rock fragments.
Diagnostic Characteristics: This scrub woodland and shrubland alliance is dominated by diagnostic species Celtis laevigata var. reticulata and/or Philadelphus lewisii, often forming dense thickets. Celtis laevigata var. reticulata occurs either as a short tree or tall shrub between 3-6 m in height. Philadelphus lewisii occurs as a tall shrub between 2-5 m in height.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: Stands included in this alliance from riparian areas in the southeastern Colorado plains and canyons in the Colorado Plateau (Carsey et al. 2003a) need further review as they may be more appropriately placed in a plains riparian alliance or Colorado Plateau seep alliance.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: Vegetation in this alliance has an open to moderately dense layer of broad-leaved deciduous small trees or shrubs forming a scrub woodland or tall shrubland less than 6 m tall.
Floristics: This scrub woodland and shrubland alliance has an upper canopy dominated by Celtis laevigata var. reticulata and/or Philadelphus lewisii, often forming dense thickets. Celtis laevigata var. reticulata occurs either as a short tree or tall shrub between 3-6 m in height. Philadelphus lewisii occurs as a tall shrub between 2-5 m in height. The short-shrub layer often contains Rosa woodsii, Rosa nutkana, or Sambucus nigra ssp. cerulea with other riparian shrubs such as Holodiscus discolor or occasionally Amelanchier alnifolia, Crataegus douglasii, Cornus sericea, Frangula purshiana (= Rhamnus purshiana), Prunus virginiana, and Symphoricarpos albus. Toxicodendron rydbergii is more abundant on moist sites. If present, the herbaceous layer has sparse to moderate cover. It is dominated by the perennial bunchgrass Pseudoroegneria spicata with smaller amounts of Aristida purpurea var. longiseta and Poa secunda. Other species include forbs such as Achillea millefolium, Erigeron pumilus, Galium aparine, Heterotheca villosa, Lotus unifoliolatus (= Lotus purshianus), Scutellaria angustifolia, Stellaria nitens, and the cactus Opuntia polyacantha. Mosses and lichens are usually present and average about 20% cover. Litter cover is relatively high. Exotic species may dominate these often disturbed stands, particularly the annual grass Bromus tectorum, but also Bromus arvensis (= Bromus japonicus), Hypericum perforatum, Melilotus officinalis, Verbascum spp., and others.
Dynamics: Celtis laevigata var. reticulata tolerates fires. It is rarely killed when burned and sprouts vigorously from underground rhizomes following a fire (FEIS 1998). However, the sprouts and seedlings may not compete well with grassland vegetation, and frequent fire is thought to exclude Celtis laevigata var. reticulata from grasslands (Johnson and Simon 1987). These stands occur on rocky slopes that are likely to have few fires (Johnson and Simon 1987). The biggest threat is exotic plants that have invaded many stands. Common exotics include annual grasses such as Bromus tectorum, Bromus arvensis, and Bromus briziformis, and the perennial forbs Hypericum perforatum and Conyza canadensis.
Environmental Description: This scrub woodland and shrubland alliance is found in the lower montane and foothill regions around the Columbia Basin, and north and east into the Central Rockies in Idaho and northwestern Wyoming and south into canyons in the Colorado Plateau and in riparian areas in the southeastern Colorado plains. It can occur in the active floodplain of intermittent streams and deep canyon bottoms of the Snake and Salmon rivers. Elevations range from 250-550 m in the Columbia Basin (Tisdale 1986) and 1400-1700 m in Colorado (Carsey et al. 2003a). The climate is temperate, continental with a mean annual precipitation of approximately 25-30 cm. Precipitation primarily occurs in the winter as snow or rain. This moisture is stored in the soil and utilized during the typically dry summers. Stands are typically found on moderately steep footslopes and toeslopes in canyons where gravel and boulder-sized colluvium accumulate; near the seepage lines on river terraces; on riparian margins and river bars; and forest openings in the mountains. Although sites are predominately on hot, dry southeastern to southwestern aspects, these trees access additional soil moisture that accumulates at the base of the colluvial slopes, or are riparian. Soils are poorly developed, well-drained alluvial or colluvial sands that often have a high percentage of rock fragments. There are reports of this alliance occurring on colluvial talus cones (Daubenmire 1970), but generally sites are more stable than adjacent Rhus glabra stands. On lowland sites surface water can be present for variable periods without detectable seasonal periodicity. Inundation is not predictable to a given season and is dependent upon highly localized rainstorms. Other adjacent stands may include other riparian vegetation and xeric grasslands dominated by Pseudoroegneria spicata or Poa secunda on the upper slopes.
Geographic Range: This scrub woodland and shrubland alliance is found in the lower montane and foothill regions around the Columbia Basin, and north and east into the Central Rockies in Idaho and northwestern Wyoming and south into canyons in the Colorado Plateau and in riparian areas in the southeastern Colorado plains.
Nations: US
States/Provinces: CA?, CO, ID, OR, WA, WY
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.900024
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
Concept Lineage: A.632 and A.939. This new alliance is composed of associations from Old Alliance II.B.2.N.a. Celtis laevigata var. reticulata Woodland Alliance (A.632) and Old Alliance III.B.2.N.c. Philadelphus lewisii Intermittently Flooded Shrubland Alliance (A.939).
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: >< Celtis reticulata Series (Tisdale 1986)
- Carsey, K., G. Kittel, K. Decker, D. J. Cooper, and D. Culver. 2003a. Field guide to the wetland and riparian plant associations of Colorado. Colorado Natural Heritage Program, Fort Collins, CO.
- Daubenmire, R. F. 1970. Steppe vegetation of Washington. Washington State University Agricultural Experiment Station Technical Bulletin No. 62. 131 pp.
- Evans, S. 1989a. Riparian survey of Washington''s Columbia Basin. Unpublished report prepared for The Nature Conservancy Washington Natural Heritage Program, Olympia, Washington.
- FEIS [Fire Effects Information System]. 1998. USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. [http://www.fs.fed.us/database/feis/]
- Faber-Langendoen, D., J. Drake, M. Hall, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, M. Russo, K. Schulz, L. Sneddon, K. Snow, and J. Teague. 2013-2019b. Screening alliances for induction into the U.S. National Vegetation Classification: Part 1 - Alliance concept review. NatureServe, Arlington, VA.
- Johnson, C. G., Jr., and S. A. Simon. 1987. Plant associations of the Wallowa-Snake Province Wallowa-Whitman National Forest. Technical Paper R6-ECOL-TP-255A-86. USDA Forest Service, Pacific Northwest Region, Wallowa-Whitman National Forest. 399 pp. plus appendices.
- Moseley, R. K. 1987a. Synecological relationships of alpine spike-fescue (Leucopoa kingii (Wats.) Weber) grasslands in eastcentral Idaho, U.S.A. Unpublished manuscript prepared for Arctic and Alpine Research. 33 pp.
- Tisdale, E. W. 1986. Canyon grasslands and associated shrublands of west-central Idaho and adjacent areas. Bulletin No. 40. Forest, Wildlife and Range Experiment Station, University of Idaho, Moscow. 42 pp.