Physiognomy and Structure: No Data Available

Floristics: This is a poorly known association, which physiognomically is typically a savanna. The broad-leaved deciduous tree Quercus garryana is the most abundant and characteristic species in the canopy. It usually has an open-grown form in which the trunk often exceeds 1 m dbh, and the boles are short in comparison to the height of the tree. The branches are massive, with spreading crowns that do not touch. Several other tree species may occur as scattered individuals, including the conifers Pinus ponderosa, Pseudotsuga menziesii, and Calocedrus decurrens (= Libocedrus decurrens). The understory is grassy and may have a component of broad-leaved deciduous shrubs less than 2 m in height. Festuca idahoensis is the dominant grass with 10-50% cover between the oaks while Elymus glaucus predominates under the oaks. Other graminoids include Pseudoroegneria spicata, Carex geyeri, Koeleria macrantha, Achnatherum occidentale (= Stipa occidentalis), and Poa spp. Forb diversity is relatively low. Most, if not all, remaining stands of this association have abundant introduced grasses in the understory as a result of livestock grazing. Species may include Bromus diandrus ssp. rigidus (= Bromus rigidus), Bromus tectorum, Cynosurus echinatus, Ventenata dubia. No other information is available.

Dynamics:  Fire may have been one of the most important factors in the maintenance of the savanna-like character of this association and the dominance of Quercus garryana. Thilenius (1968) reports that most stands of Quercus garryana savanna in the Willamette Valley have a few scattered savanna-form trees in a much denser matrix of sapling and pole-sized trees, as well as forest-form trees (tall, relatively thin trunks with small ascending branches).