[3] These areas do, however, lack the reoccurring low intensity fires which once occurred throughout northern Michigan, impacting regeneration of red pine and eastern hemlock, as well as leading to an increased content of hardwood species such as sugar maple and beech.

Salling Hansen Lumber Company heavily logged much of the property within Hartwick Pines State Park during the 1880s and 1890s.

It contains recreated exhibit rooms, photographs and artifacts of the lumber boom years of northern Michigan.

The state park includes a campground, day-use area, and network of four-season trails for summer hiking and winter cross-country skiing.

The wooded Au Sable River foot trail is approximately three miles in length and takes hikers across the East Branch at two different locations.

The Mertz Grade Trail winds through forest and field for approximately two miles and was named for the early logging railroad spur it shares for a portion of its distance.