Haymeadow Flowage features a core of open and wooded wetland communities associated with the Haymeadow Creek and Flowage. Of note are old-growth hemlock-hardwood stands that are rare on this landtype on the Nicolet. There is good representation of the mature and seral stage forest communities that naturally occur on these rather dry and nutrient-poor habitat types. Wetlands range from open water and areas of cattails and floating sedge hummocks in the flowage proper, to black spruce muskeg-type bogs, mainly to the north of Haymeadow Creek. Several mixed conifer swamps with significant white-cedar components are scattered throughout the site, though none contain extensive areas of closed-canopy white-cedar. A high-quality open bog with two small bog lakes is located on the north edge of the complex. Several large red pine-dominated islands occur within the wetland matrix. Surrounding uplands are generally rolling pitted sandy outwash with some steep slopes bordering lowlands. A variety of communities occur, from stands of old growth hemlock-hardwoods to healthy younger mixed forests of red and white pine, red oak, red maple, and paper birch on the dryer, sandier soils. Most of the better upland stands are north of Haymeadow Creek, often in fairly narrow bands on steep slopes bordering lowlands. Ecological gradients are generally intact. Most upland stands have a mature pine component, often super-canopy white pine, with 26-30 inches in diameter fairly common in a few stands. Hemlock sizes are comparable, with one measured at 40 inches in diameter. The best stands exhibit a pronounced old-growth structure. Haymeadow Flowage is owned by the US Forest Service and was designated a State Natural Area in 2007.