'In Oregon, the tree grows on the west side of the Cascade Range, primarily in the Willamette, Umpqua and Rogue River valleys, and along the Columbia River Gorge, as well as in canyons adjacent to the gorge" 

It is a drought-tolerant tree. Older specimens are often affected by heart rot.

The acorns are consumed by wildlife and livestock. David Douglas recorded that bears consumed them. "

 

"Quercus garryana woodlands create a landscape mosaic of grassland, savanna, woodland, and closed-canopy forest. This mosaic of varied habitats, in turn, allows many more species to live in this area than would be possible in coniferous forest alone. Parks Canada states that Garry oak woodlands support more species of plants than any other terrestrial ecosystem in British Columbia. 

 It grows in a variety of soil types, for instance, rocky outcrops, glacial gravelly outwash, deep grassland soils, and seasonally flooded riparian areas." 

" Oregon white oak woodlands in British Columbia and Washington are critical habitats for a number of species that are rare or extirpated in these areas, plant, animal, and bryophyte: 

Propertius duskywing butterfly Erynnis propertius, sole larval food plant is oak

Bucculatrix zophopasta leaf-mining moth, sole larval food plant is oak

Lewis woodpecker Melanerpes lewis

Slender billed nuthatch Sitta carolinensis aculeata

Sharp tailed snake Contia tenuis

Western gray squirrel Sciurus griseus

Western tanager Piranga ludoviciana

Western wood peewee Contopus sordidulus

Western bluebird Sialia mexicana

Sessile trillium Trillium parviflorum

Banded cord-moss Entosthodon fascicularis

Apple moss Bartramia stricta

(liverwort) Riccia ciliata

Golden Paintbrush Castilleja levisecta 

https://en.wikipedia.org/wiki/Quercus_garryana 

 

'The mildly sweet (but perhaps unpalatable) acorns are edible, ideally after leaching. The bitterness of the toxic tannic acid would likely prevent anyone from eating enough to become ill. 

 Native Americans ate the acorns raw and roasted, also using them to make a kind of flour."