Habitat
It grows well on a variety of soil types, ranging from gravel to clay loams. It occurs more often on poorly-developed soils with 0.5 to 2.0 percent organic matter content (Pase and Brown, 1982). Sites are typically dry canyons or gulches with full exposure to sunlight and range from 3,000 to 11,000 feet (910-3,300 m) elevation (Munz and Keck, 1973). Singleleaf ash also colonizes talus slopes, dry hillsides, and alluvial deposits (Little, 1950; Vines, 1960]. Common plant associates of singleleaf ash include skunkbush sumac (Rhus trilobata), desert ceanothus (Ceanothus greggii), Arizona rosewood (Vequelinia californica), desert barberry (Mahonia fremontii), chokecherry (Prunus virginianus), and mountain-mahogany (Cercocarpus spp.) (Pase et al., 1982). It grows around springs in valley bottoms, in stream canyons and other well-watered habitats in lower mountains (4000 to 6000 feet), and on relatively dry hillsides at higher elevations up to 11,000 feet (Beatley, 1976; Rhode, 2002). Subspecies lowelli is local in moist soils along streams and canyons; in oak wood and upper desert zones. In Utah it is generally found in canyons along streams or locations where moisture collects.
Reproduction
Sexual: Singleleaf ash samaras are mature by late summer or fall and are dispersed by wind shortly thereafter. Samaras are dormant, requiring warm, then cold stratification. Germination is epigeal and may occur the spring following dispersal. Samaras, however, can remain viable in leaf litter or humus for several years (Reed, 1993). Vegetative: Most ash species sprout from the root crown after logging or fire has removed aboveground portions of the plant (Barnes, 1985; Burns and Honkala, 1990). It is probable that singleleaf ash responds in such a manner.