DISTRIBUTION AND OCCURRENCE
SPECIES: Toxicodendron diversilobum | Poison-Oak 



GENERAL DISTRIBUTION : 
Poison-oak is distributed from Baja California north to British Columbia
[31,45,58].  It occurs west of the Cascade Range in Washington, Oregon,
and California [32] and is ubiquitous in California west of the Sierra
Nevada and the Mojave Desert [38].


ECOSYSTEMS : 
   FRES20  Douglas-fir
   FRES21  Ponderosa pine
   FRES24  Hemlock - Sitka spruce
   FRES27  Redwood
   FRES28  Western hardwoods
   FRES34  Chaparral - mountain shrub


STATES : 
     CA  OR  WA  MEXICO  BC


ADMINISTRATIVE UNITS : 
     CHIS  KICA  LAVO  OLYM  PINN  PORE
     REDW  SAMO  SEQU  WHIS  YOSE


BLM PHYSIOGRAPHIC REGIONS : 
    1  Northern Pacific Border
    2  Cascade Mountains
    3  Southern Pacific Border
    4  Sierra Mountains


KUCHLER PLANT ASSOCIATIONS : 
   K001  Spruce - cedar - hemlock forest
   K002  Cedar - hemlock - Douglas-fir forest
   K005  Mixed conifer forest
   K006  Redwood forest
   K009  Pine - cypress forest
   K010  Ponderosa shrub forest
   K026  Oregon oakwoods
   K028  Mosaic of K002 and K026
   K029  California mixed evergreen forest
   K030  California oakwoods
   K033  Chaparral
   K034  Montane chaparral
   K035  Coastal sagebrush


SAF COVER TYPES : 
   213  Grand fir
   222  Black cottonwood - willow
   224  Western hemlock
   229  Pacific Douglas-fir
   230  Douglas-fir - western hemlock
   231  Port Orford-cedar
   232  Redwood
   233  Oregon white oak
   234  Douglas-fir - tanoak - Pacific madrone
   235  Cottonwood - willow
   243  Sierra Nevada mixed conifer
   244  Pacific ponderosa pine - Douglas-fir
   245  Pacific ponderosa pine
   246  California black oak
   247  Jeffrey pine
   248  Knobcone pine
   249  Canyon live oak
   250  Blue oak - Digger pine
   255  California coast live oak


SRM (RANGELAND) COVER TYPES : 
NO-ENTRY


HABITAT TYPES AND PLANT COMMUNITIES : 
Poison-oak occurs in mixed evergreen forests [29,30,32,59], woodlands,
chaparral, [25,26,27], coastal sage scrub [39], and riparian zones
[25,26,27,39,58].  It is the most widespread shrub in California [7].
Holland [33] described a poison-oak chaparral community type that may be
maintained by frequent fire.  Because it is dominated by poison-oak,
little is known of its community composition.

Many of the plant species commonly associated with poison-oak were
previously listed under DISTRIBUTION AND OCCURRENCE information.  Other
common associates follow, listed by community type.

Associates in mixed evergreen forests include Pacific madrone (Arbutus
menziesii), sugar pine (Pinus lambertiana), bigleaf maple (Acer
macrophyllum), tanoak (Lithocarpus densiflorus), California bay
(Umbellularia californica), and chinquapin (Chrysolepsis chrysophylla)
[11,17,18,43].

Woodland associates include valley oak (Quercus lobata), interior live
oak (Q. wislizenii), Monterey pine (Pinus radiata) [42], Coulter pine
(P. coulteri) [9], bigcone Douglas-fir (Pseudotsuga macrocarpa) [8,64],
and California walnut (Juglans californica) [48].

Chaparral associates include toyon (Heteromeles arbutifolia), chamise
(Adenostoma fasciculatum), and California scrub oak (Quercus dumosa).
Coastal sage scrub associates include California sagebrush (Artemesia
california), coyotebrush (Baccharis pilularis), and sugar sumac (Rhus
ovata) [6,26,27,47,65].

Poison-oak associates in riparian zones include bigleaf maple,
California sycamore (Plantus racemosa), white alder (Alnus rhombifolia),
[17], boxelder (Acer negundo), willow (Salix spp.), California
blackberry (Rubus vitifolius), toyon, and wild grape (Vitis spp.)  [69].

Published classifications naming poison-oak as a dominant part of the
vegetation are:

Description and classification of the forests of the upper Illinois
   River drainage of southwestern Oregon [1]
Preliminary plant associations of the Siskiyou Mountain Province [2]
Coast redwood ecological types of southern Monterey County, California [10]
Plant communities of Santa Rosa Island, Channel Islands National Park [14]
Plant association and management guide: Siuslaw National Forest [29]
Plant association and management guide: Willamette National Forest [30]
The community composition of California coastal sage scrub [39]
Plant associations within the Interior Valleys of the Umpqua River
   Basin, Oregon [55] 
The vascular plant communities of California [59]
An introduction to the plant communities of the Santa Ana and San
   Jacinto Mountains [65].

Related categories for Species: Toxicodendron diversilobum | Poison-Oak