Nature

Straight Lake State Park is in the Forest Transition Ecological Landscape of Wisconsin. This landscape stretches from Polk County in northwest Wisconsin to Menominee County in northeast Wisconsin. Straight Lake is also located within the tension zone, a unique area where both northern and southern plant and animal species can be found in the same place.

With over 2,000 acres, Straight Lake State Park contains many different habitats and unique characteristics. The park has a large, intact forest with trees that are approaching 100 years old. Large intact forests are becoming increasingly rare due to development and fragmentation. The large forest within the park provides high-quality forest habitat for many species, including those that are threatened or of special concern. This 457-acre section of the park is known as the Tunnel Channel Woods State Natural Area.

Another special landscape located in the park is the Tamarack Fen State Natural Area. This area is on the western end of Straight Lake. It is a diverse wetland complex that includes hardwood swamp, sedge meadow, alder ticket and some tamarack swamp. This 85-acre section of the park is home to rare species and highlights the importance of high-quality wetlands.

Water is abundant in the park with Straight and Rainbow lakes and many ephemeral ponds scattered throughout the property. Ephemeral ponds are small, shallow, temporary water bodies that hold water for a brief period of time, such as after snowmelt or heavy rains. Because they are temporary water bodies, these ponds lack fish, which results in great habitat for amphibians and invertebrates.

Straight Lake is a drainage lake, the Straight River enters the lake on the west side and then flows out on the east end. Straight Lake was originally created for logging, and then local residents built an earthen dam. In 2014, the earthen dam was replaced with a sheet-piling dam and the spillway was expanded. Straight Lake offers a variety of different fish species such as northern pike, bass and panfish. Rainbow Lake is a seepage lake, meaning there is no inlet or outlet. All water in Rainbow Lake is from precipitation and groundwater. Because of this, rainbow trout are stocked each year in spring and fall. Both lakes are entirely undeveloped and provide critical habitat for a variety of species.

With the diverse habitats located within the park, Straight Lake has been nominated as an important bird area by the Wisconsin Bird Conservation Initiative. Species known to use the park include bald eagles, trumpeter swans, cerulean warblers, and red-shouldered hawks, among others. Common mammals seen in the park include white-tailed deer, black bear, fisher and otter. Many different species of amphibians and reptiles can be found as well.