Common vegetation in Boulder River Wilderness includes old-growth Douglas fir, true fir, western hemlock, and western red cedar, as well as bigleaf maple, alder, willow, and devil's club.
Mapleton was likely named by Julia Ann Bean ("Grandma" Bean) for the abundance of Bigleaf Maple trees in the area.
Here, the river trail descends 300 feet in half a mile passing though temperate rain forest with moss covered Bigleaf Maple, Douglas-fir, Sword Fern and Salal and places to step off the trail and rest or enjoy the scenery.
Acer saccharinum | Acer saccharum | Acer pseudoplatanus | Acer macrophyllum | Acer Inc. | Acer platanoides | Acer rubrum | Acer palmatum | Acer pictum subsp. mono | Phoradendron macrophyllum | Norway Maple (''Acer platanoides'') | Manitoba Maple (''Acer negundo'') | Geum macrophyllum | Acer sempervirens | Acer heldreichii | ''Acer griseum | Acer davidii | ''Acer'' |
Along the trail there is a side path of 200 feet that leads to a grove of maple trees covered with epiphytic spikemoss (the "Hall of Mosses").
The forests in the watershed include a wide variety of vegetation, including Douglas-fir, bigleaf maple, madrone, typical of the Southern Oregon Coast Range, coastal Siskiyou Mountains, and the Redwoods Zone.