Middle Santiam River

Middle Santiam Research Natural Area (RNA) was established to represent old growth Douglas-fir-western hemlock forests in the western Oregon Cascades.  The RNA has steep, north-facing slopes on the south block and south facing-slopes on the north block. The bedrock is composed of igneous flow and pyroclastic rocks. Three tributaries of the Middle Santiam River lie within the boundaries of the RNA. Douglas fir (Pseudotsuga menziesii) is the dominant species in s majority of the north unit. Other common species of the north unit include: Pacific madrone (Arbutus menziesii), sugar pine (Pinus lambertiana), creambush oceanspray (Holodiscus discolor), Pacific poison oak (Rhus diversiloba), western fescue (Festuca occidentalis), and Oregon iris (Iris tenax). Douglas fir and western hemlock (Tsuga heterophylla) co-dominate the overstory of the south unit. Western redcedar (Thuja plicata) and Pacific silver fir (Abies amabilis) are also common in the south unit.