For example, such as red from red alder or western red cedar. Common hardwoods include bigleaf maple and red alder. Hardwoods including tanoak, bigleaf maple, red alder, and Pacific madrone are common. Riparian zones support red alder and bigleaf maple forests. Nest tree species may include Douglas fir, western redcedar, western hemlock and red alder. Common associates include Western hemlock, Sitka spruce, red alder and bigleaf maple. Some western hemlock, western red cedar, grand fir, red alder and bigleaf maple also occur. Other trees that sometimes dominate forest areas include black cottonwood and red alder. It is also characterised by bigleaf maple, red alder, sword fern, and red huckleberry. Red alder seeds have a membranous winged margin that allows long-distance dispersal. Red alder does not thrive in heavy, wet clay soils. Red alder is associated with coast Douglas-fir "Pseudotsuga menziesii" subsp. Because of its abundance, red alder delivers large amounts of nitrogen to enrich forest soils. Native Americans used red alder bark to treat poison oak, insect bites, and skin irritations. Rocky Mountain Maple, Red Alder, Paperbark Birch, Chokecherry, cottonwood, and poplar.