WILLOW-HAWTHORN SHRUBLAND (87)

Geographic Distribution. Valley bottom riparian shrubland formerly widespread along low gradient streams. Currently most prevalent in the Willamette and Grand Ronde River Valleys.

Structure and Appearance. Tall shrubland with dense cover of willows (Salix spp.) and/or black hawthorn (Crataegus douglasii). Shrubs are interspersed with dense patches of spirea and sedge meadows in poorly drained reaches and tufted hairgrass (Deschampsia caespitosa) prairie on better drained soils.

Composition. Overstory willow species include (Salix sitchensis, S. rigida, S. fluviatilis, in western Oregon, and S. lasiandra, S. exigua, S. geyeriana, and S. lutea) in eastern Oregon. Black hawthorn is generally present in varying degrees of dominance. Other western Oregon shrubs include blackberry (Rubus ursinus and R. spectabilis), sticky currant (Ribes lacustre), Indian plum (Oemleria cerasiformis), and Douglas spirea (Spiraea douglasii).

Eastern Oregon shrubs include western birch (Betula occidentalis), snowberry (Symphoricarpos albus), mockorange (Philadelphus lewisii), and red osier dogwood (Cornus sericea).

Forbs and grasses common to this type include cowparsnipcow-parsnip (Hieracleum lanatum), stinging nettle (Urtica dioica), common rush (Juncus effusus), horsetail (Equisetum arvense), camas (Camassia quamash), tufted hairgrass, buttercup (Ranunculus occidentalis), marsh sedge (Carex obnupta), bluejoint reedgrass (Calamagrostis canadensis), and blue wildrye (Elymus glaucus).

Landscape Setting. This type occurs on broad, low elevation floodplains that seasonally flood and maintain high water tables. Agriculture or other wetland/riparian types usually border this shrub dominant type.

References. Klock 1998, Chappell et al. 1998, Kagan and Caicco 1992, Kovalchik 1986.