DISTRIBUTION AND OCCURRENCE
SPECIES: Crataegus douglasii | Douglas Hawthorn 



GENERAL DISTRIBUTION : 
The most widespread occurrence of Douglas hawthorn is in the Pacific
Northwest, from southeastern Alaska south through British Columbia,
Alberta, Washington, and Oregon to northern California.  Inland
distribution encompasses northern Nevada, Utah, Colorado, and Wyoming,
western Montana, and Idaho. Douglas hawthorn may also be found as a
disjunct in northern Michigan, Minnesota, Sasketchewan, and southern
Ontario [3,24,33,37].

Contradictory information concerning the distribution of Douglas
hawthorn is plentiful.  Many sources [4,19,30] include populations
distributed into the Dakotas, and isolated disjuncts in New Mexico,
Arizona, and Texas.  Stiles [35] claims to have sampled fruits and seeds
of Douglas hawthorn from the Eastern deciduous forests (40 degrees N).
Others [5,6,14,34] have shown no distribution east of Montana (excluding
the Great Lakes disjunct) or south of Utah.  The basis of these
contradictions may be the inclusion of Douglas hawthorn varieties in
some botanical range maps.  The information presented above is assumed
to be the true distribution of C. douglasii var. douglasii.


ECOSYSTEMS : 
   FRES20  Douglas-fir
   FRES21  Ponderosa pine
   FRES28  Western hardwoods
   FRES29  Sagebrush
   FRES34  Chaparral - mountain shrub
   FRES35  Pinyon - juniper
   FRES36  Mountain grasslands


STATES : 
     AL  CA  CO  ID  MN  MT  NV  OR  UT  WA
     WY  AB  BC  ON  SK


ADMINISTRATIVE UNITS : 
     BICA  CODA  GLAC  GRTE  GRSA  ISRO
     NOCA  OLYM  PIRO  REDW  TICA


BLM PHYSIOGRAPHIC REGIONS : 
   1  Northern Pacific Border
   2  Cascade Mountains
   3  Southern Pacific Border
   4  Sierra Mountains
   5  Columbia Plateau
   6  Upper Basin and Range
   8  Northern Rocky Mountains
   9  Middle Rocky Mountains


KUCHLER PLANT ASSOCIATIONS : 
   K023  Juniper - pinyon woodland
   K037  Mountain-mahogany - oak scrub
   K038  Great Basin sagebrush
   K051  Wheatgrass - bluegrass
   K055  Sagebrush steppe


SAF COVER TYPES : 
   220  Rocky Mountain juniper
   238  Western juniper
   239  Pinyon - juniper
   241  Western juniper


SRM (RANGELAND) COVER TYPES : 
NO-ENTRY


HABITAT TYPES AND PLANT COMMUNITIES : 
Douglas hawthorn generally occurs as an understory dominant in plant
community types, or associations.  It mostly occurs as an understory
species within sites dominated by black cottonwood (Populus
trichocarpa), eastern cottonwood (P. deltoides), quaking aspen (P.
tremuloides), or ponderosa pine (Pinus ponderosa).  In western Montana,
Douglas hawthorn has been described as a nonextensive riparian dominance
type [17].  Pure stands of Douglas hawthorn typically have an understory
occupied by Wood's rose (Rosa woodsii), chokecherry (Prunus virginiana),
or common snowberry (Symphoricarpos albus).  In west-central Montana,
Douglas hawthorn exhibited at least 5 percent cover value within the
tufted hairgrass (Deschampsia cespitosa) community type [28].

Publications listing Douglas hawthorn as an indicator or dominant
species in habitat types (hts), community types (cts), or dominance
types (dts) are presented below:

Area             Classification              Authority

   MT            Riparian dts                Hansen and others 1988
   WA            Steppe hts                  Daubenmire 1970
ne OR            Riparian cts                Kauffman and others 1985

Related categories for Species: Crataegus douglasii | Douglas Hawthorn