sentences:  Black cottonwood grows on alluvial sites, riparian habitats, and moist woods on mountain slopes, at elevations of 0–2100(–2750) meters.It often forms 
  extensive stands on bottomlands of major streams and rivers at low elevations along the Pacific Coast, 
  west of the Cascade Range.In eastern Washington and other dry areas, it is restricted to protected 
  valleys and canyon bottoms, along streambanks, and edges of ponds and meadows.