Upper Tomahawk River Pines features several undisturbed stands of large red pine located along a wild and undeveloped reach of the Tomahawk River. The even-aged pines originated following wildfire and are gradually succeeding to white pines, which dominate the understory. The pines are growing on elevated islands separated from the forested uplands by vast wetlands of alder shrub swamp and swamp conifers. These isolated red pine islands provide nesting sites for bald eagles and harbor a characteristic groundlayer with bracken fern, wintergreen, and barren strawberry. Alder thickets cover most of the wetlands on both sides of the Tomahawk River with a few areas of tamarack and black spruce. The meandering Tomahawk River is a slow, warm, soft water stream containing a diverse snail fauna in the muck bottom but with relatively few aquatic plants. Birds include gray jay, boreal chickadee, alder flycatcher, veery, and pine warbler. Upper Tomahawk River Pines is owned by the DNR and was designated a State Natural Area in 1990.