DOUGLAS FIR-PORT ORFORD CEDAR FOREST (50)

Geographic Distribution. A low to mid elevation forest type found mainly in the Coast Range and Siskiyou Mountains of Curry County of southwestern Oregon. This type does not grow north of Coos Bay on the Oregon coast and Roseburg in the interior valleys. Common west of the Coast Range Crest, but is largely restricted to moist ultramafic soil environments inland. This cover type is mostly confined to moist habitats of moderate elevation and steep riparian situations.

Structure and Appearance. This conifer forest type is characterized by, multi-story tree canopies, co-dominated by Port Orford cedar (Chamaecyparis lawsoniana), and Douglas fir (Pseudotsuga menziesii). Sub-canopies are composed of conifers and evergreen deciduous trees where there is discontinuous overstory canopy cover.

Composition. Douglas fir and Port Orford cedar dominate canopy overstory in these stands. Western hemlock (Tsuga heterophylla) is common west of the Coast Range, and sugar pine (Pinus lambertiana) and grand fir (Abies grandis) present in the overstory of interior stands.

Understory conifers are Douglas fir, western hemlock, western yew (Taxus brevifolia) and Port Orford cedar. On ultramafic substrates, sugar pine and western white pine (Pinus monticola) are frequent associates. Evergreen deciduous trees are California laurel (Umbellaria californica), tanoak (Lithocarpus densiflora), and chinquapin (Castanopsis chrysophylla).

Large stature shrubs are common west of the Coast Range crest, vine maple (Acer circinatum), pacific rhododendron (Rhododendron macrophyllum), and red huckleberry (Vaccinium parvifolium), and evergreen huckleberry (V. ovatum). Interior stands shrub layers contain western azalea (Rhododendron occidentalis), Sadler oak (Quercus sadleriana), and dwarf OregongrapeOregon-grape (Mahonia nervosa).

Herbaceous layers are rich in species and abundance. Swordfern (Polystichum munitum) and other ferns, bracken (Pteridium aquilinum), deer fern (Blechnum spicant), and lady fern (Athyrium filix-femina) are common. Other forbs include: vanillaleaf (Achlys triphylla), bedstraw (Galium triflorum), western iris (Iris tenax), Oregon oxalis (Oxalis oregana), redwoods violet (Viola sempervirens), western starflower (Trientalis latifolia), rattlesnake plantain (Goodyera oblongifolia), and white trillium (Trillium ovatum).

Landscape Setting. This cover type is under-represented in the mapping effort because it often exists as a coniferous riparian type that is not extensive enough to be mapped. It is largely transitional to the other Douglas fir conifer types found in the region.

References. Atzet and Wheeler 1983, Jimerson et al. 1995, Atzet et al. 1996, Frenkel and Kiilsgaard 1984, Hawk 1978, Hawk and Zobel 1980