DOUGLAS FIR DOMINANT/ MIXED CONIFER FOREST (56)

Geographic Distribution. Common mid elevation forest type in southwestern Oregon. This type also extends north to the Columbia River in a narrow band along the eastern side of the Cascades.

Structure and Appearance. Stand structure can be diverse in undisturbed late seral stands although single story forest canopies typify the type. Overstory tree layer ranges widely in canopy closure based on management practice, disturbance history, and microsite. Understory vegetation is usually diverse and rich in species.

Composition. This cover type contains a diverse array of conifers that complement the ever-present Douglas fir (Pseudotsuga menziesii). Fir (Abies grandis and/or A. concolor), incense cedar (Calocedrus decurrens), western white pine (Pinus monticola), and ponderosa pine (P. ponderosa) are found throughout the range. Sugar pine (P. lambertiana) occurs only in southwestern Oregon, and western red cedar (Thuja plicata), and Engelmann spruce (Picea engelmannii) only in the central and northern regions of the Cascades. Sub-canopy layer generally has the shade tolerant components of the overstory. Western yew (Taxus brevifolia) is a frequent sub-canopy component in southwestern Oregon.

Indicator shrubs in this cover type include: vine maple (Acer circinatum), Rocky mountain maple (A. glabrum var. douglasii), serviceberry (Amelanchier alnifolia), greenleaf manzanita (Arctostaphylos patula), pinemat manzanita (A. nevadensis), red huckleberry (Vaccinium parvifolium), Oregon grapeOregon-grape (Mahonia nervosa), snowberry (Symphoricarpos albus), oceanspray (Holodiscus discolor), sticky currant (Ribes viscosissimum), and squaw currant (R. cereum).

Common herbs in this cover type include western yarrow (Achillea millefolium), silvery lupine (Lupinus argenteus), tailcup lupine (L. caudatus), strawberry (Fragaria virginiana), bull thistle (Cirsium vulgare), heartleaf arnica (Arnica cordifolia), peavine (Lathyrus lanszwertii), starry solomon-plume (Smilacina stellata), and white vein pyrola (Pyrola picta).

Landscape Setting. In southwestern Oregon this mid-elevation forest transitions between the deciduous dominant foothill forests and the true fir dominant montane conifers. Along the slopes of the eastern Cascades it is also transitional to the ponderosa pine and ponderosa/western juniper at its low end and montane forests at upper elevations.

References. Hopkins and Rawlings 1985, Atzet et al. 1996, Atzet and Wheeler 1983, Chappell et al. 1999, Kovalchik 1986, Volland 1985.