Thuja plicata
Vegetation in the Salmo-Priest Wilderness is primarily dominated by Subalpine Fir Zone with Alpine zones on the ridgelines, and Western Red Cedar/Western Hemlock in valley bottoms (primarily of the South Salmo River). The wilderness contains the largest old growth forest in eastern Washington. Tree species include western red cedar, western hemlock, Douglas fir, ponderosa pine, grand fir, western larch, subalpine fir, whitebark pine, englemann spruce, quaking aspen, and cottonwood. Plant association groups include Pseudotsuga menziesii/Symphoricarpos albus, Abies lasiocarpa/Clintonia uniflora, Abies lasiocarpa/Rhododendron albiflorum, Abies lasiocarpa/Rhododendron albiflorum-Xerophyllum tenax, Abies lasiocarpa/Xerophyllum tenax, Tsuga heterophylla/CUntonia uniflora, Tsuga heterophylla/Gymnocarpium dryopteris, Tsuga heterophylla/Menziesia ferruginea, Tsuga heterophylla/Rubus pedatus, Tsuga heterophylla/Xerophyllum tenax, Thuja plicata/Clintonia uniflora, Thuja plicata/Vaccmium membranaceum, and Pinus albicaulis.