mpqua Valley of Oregon were similar to the xeric Oregon white oak/Pacific poison-oak association of the Willamette Valley; a sixth was a riparian association dominated by Oregon white oak and Oregon ash (Fraxinus latifolia) (62). In California, four communities dominated by Oregon white oak were found in the Bald Hills woodlands of Redwood National Park (70) and three communities dominated by Oregon white oak or related hybrids were identified in a limited area on Bennett Mountain (75). The shin oak brush association, largely composed of Oregon white oak, is a distinctive plant community in Kern and Los Angeles Counties (76).
The composition of Oregon white oak communities varies greatly because of differences in soil, topography, and climate, and in fire and grazing histories. Because of proximity to farmlands, many communities include introduced forbs and grasses. Pacific poison-oak (Rhus diuersiloba) and common snowberry (Symphoricarpos albus) are probably the most widespread and characteristic shrub associates.
Species often found with Oregon white oak are listed in table 1. The listing is not exhaustive; it just indicates the great variety of common associates. Species associated with Oregon white oak in chaparral communities and on serpentine soils are listed in other sources (15,16,79).
|Abies grandis||Amorpha californica||Agropyron spicatum|
|Acer circinatum||Arctostaphylos columbiana||Agrostis spp.|
|Acer glabrum||Arctostaphylos manzanita||Allium spp.|
|Acer macrophyllum||Arctostaphylos media||Athysanus pusillus|
|Aesculus californica||Arctostaphylos uva-ursi||Avena barbata|
|Alnus rubra||Berberis aquifolium||Balsamorhiza deltoides|
|Amelanchier alnifolia||Berberis nervosa||Brodiaea spp.|
|Arbutus menziesii||Ceanothus cuneatus||Bromus spp.|
|Betula occidentalis||Ceanothus integerrimus||Camassia spp.|
|Castanopsis chrysophylla||Ceanothus velutinus||Carduus pycnocephalus|
|Cercocarpus betuloides||Cornus stolonifera||Carex spp.|
|Cornus nuttallii||Crataegus oxyacantha||Chlorogalum pomeridianum|
|Corylus cornuta||Cytisus scoparius||Collinsia spp.|
|Crataegus douglasii||Gaultheria shallon||Crocidium multicaule|
|Fraxinus latifolia||Hedera helix||Cynosurus echinatus|
|Heteromeles arbutifolia||Holodiscus discolor||Dactylis glomerata|
|Juniperus scopulorum||Osmaronia cerasiformis||Danthonia californica|
|Libocedrus decurrens||Philadelphus lewisii||Delphinium menziesii|
|Lithocarpus densiflorus||Physocarpus capitatus||Dentaria californica|
|Pinus contorta||Purshia tridentata||Dodecatheon hendersonii|
|Pinus monticola||Rhus diversiloba||Dryopteris arguta|
|Pinus ponderosa||Ribes sanguineum||Elymus glaucus|
|Pinus sabiniana||Rosa eglanteria||Eriogonum nudum|
|Populus tremuloides||Rosa gymnocarpa||Eriophyllum lanatum|
|Populus trichocarpa||Rosa nutkana||Erythronium oregonum|
|Prunus avium||Rubus laciniatus||Festuca spp.|
|Prunus emarginata||Rubus parviflorus||Fritillaria lanceolata|
|Prunus virginiana||Rubus procerus||Galium spp.|
|Pseudotsuga menziesii||Rubus ursinus||Holcus lanatus|
|Pyrus communis||Spiraea betulifolia||Hypericum perforatum|
|Pyrus fusca||Spiraea douglasii||Lathyrus spp.|
|Pyrus malus||Symphoricarpos albus||Lomatium utriculatum|
|Quercus agrifolia||Symphoricarpos mollis||Lonicera ciliosa|
|Quercus chrysolepis||Symphoricarpos rivularis||Lotus micranthus|
|Quercus douglasii||Vaccinium ovatum||Lupinus spp.|
|Quercus kelloggii||Vaccinium parvifolium||Melica geyeri|
|Rhamnus purshiana||Viburnum ellipticum||Mimulus spp.|
|Salix spp.||Montia spp.|
|Sambucus cerulea||Nemophila heterophylla|
|Taxus brevifolia||Osmorhiza spp.|
|Thuja plicata||Phacelia linearis|
|Tsuga heterophylla||Platyspermum scapigera|
|Umbellularia californica||Plectritis spp.|
¹ Sources: 4,10,11,13,20,22,24,28,31,32,35,42,47,54,62,63,67,69,70,71,72,73,75,78
Flowering and Fruiting- Oregon white oak flowers somewhat later in the spring than many of its associates. Flowering has been noted in March, April, May, and June (72,74), but the seasonal span is probably greater over the wide range of latitudes and elevations where this species occurs. Fl