Garry Oak

Appearance

It is a drought-tolerant tree, typically of medium height, growing slowly to around 20 m or as a shrub to 3 to 5 metres tall. It has the characteristic oval profile of other oaks when solitary, but is also known to grow in groves close enough together that crowns may form a canopy. The leaves are deciduous, 5–15 cm long and 2–8 cm broad, with 3-7 deep lobes on each side. The flowers are catkins, the fruit a small acorn 2–3 cm long and 1.5–2 cm broad, with shallow, scaly cups.

The Oregon white oak is commonly found in the Willamette Valley hosting the mistletoe ''Phoradendron flavescens''. It is also commonly found hosting galls created by wasps in the family Cynipidae. 'Oak apples', green or yellow ball of up to 5 cm in size, are the most spectacular. They are attached to the undersides of leaves. One common species responsible for these galls is ''Cynips maculipennis''. Other species create galls on stems and leaves. Shapes vary from spheres to mushroom-shaped to pencil-shaped.


In British Columbia, the Garry oak can be infested by three nonnative insects: the jumping gall wasp ''Neuroterus saltatorius'', the oak leaf phylloxeran, and the gypsy moth.

While the invasive plant disease commonly called Sudden Oak Death attacks other Pacific Coast native oaks, it has not yet been found on the Garry oak. Most oak hosts of this disease are in the red oak group, while Garry oak is in the white oak group.

Evolution

Garry oak is the only native oak species in British Columbia, Washington, and northern Oregon. In these areas, Garry oak woodlands are seral, or early-successional – they depend on disturbance to avoid being overtaken by Douglas-fir . The disturbance allowing Garry oak to persist in an area that would otherwise succeed to coniferous forest was primarily fire. Natural wildfires are relatively common in the drier portions of the Pacific Northwest where Garry oak is found, but fire suppression has made such events much less common. In addition, early settlers' records, soil surveys, and tribal histories indicate that deliberate burning was widely practiced by the indigenous people of these areas. Fire perpetuated the grasslands that produced food sources such as camas, chocolate lily, bracken fern, and oak; and that provided grazing and easy hunting for deer and elk. Mature Garry oaks are fire-resistant, and so would not be severely harmed by grass fires of low intensity. Such fires prevented Douglas-fir and most other conifer seedlings from becoming established, allowing bunch grass prairie and Garry oak woodland to persist. Fire also kept oak woodlands on drier soils free of a shrub understory. Wetter oak woodlands historically had a substantial shrub understory, primarily snowberry.


Garry 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''
⤷  ''Riccia ciliata''


Garry oak 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.

The Donation Land Claim Act of 1850 encouraged Anglo settlement of Washington and Oregon, and marked the beginning of the end of regular burning by Indians of the area . The arrival of Europeans also reduced the number of natural fires that took place in Garry oak habitat. With fire suppression and conversion to agriculture, Garry oak woodlands and bunch grass prairies were invaded by Douglas-fir, Oregon ash , and imported pasture grasses. Oaks were logged to clear land for pasture, and for firewood and fence posts. Livestock grazing trampled and consumed oak seedlings. By the 1990s, more than half the Garry oak woodland habitat in the South Puget Sound area of Washington was gone. On Vancouver Island, more than 90% was gone. Remaining Garry oak woodlands are threatened by urbanization, conversion to Douglas-fir woodland, and invasion by shrubs, both native and nonnative .
Conversely, oak groves in wetter areas that historically had closed canopies of large trees are becoming crowded with young oaks that grow thin and spindly, due to lack of fires that would clear out seedlings.

Uses

Although the wood has a beautiful grain, it is difficult to season without warping, and therefore the Garry oak has not historically been regarded as having any commercial value and is frequently destroyed as land is cleared for development. However, Garry oaks and their ecosystems are the focus of conservation efforts, including in communities such as Tacoma, Washington, where an Oak Tree Park has been established, Oak Bay, British Columbia, which is named after the tree, and Corvallis, Oregon. Moreover, recently the wood, which is similar to that of other white oaks, has been used experimentally in Oregon for creating casks in which to age wine.
When used as firewood, garry oak produces 28 million BTUs per cord burned.

In Oak Bay, British Columbia, a fine of up to $10,000 may be issued for each Garry oak tree cut or damaged.