Peters Mountain was once covered with an old-growth forest of white pine and hemlock trees. These trees were cut down during the lumber era that swept throughout the mountains of Pennsylvania during the mid-to late 19th century. The largely coniferous forest was replaced by the mixture of hardwood trees that are seen today at the Joseph E. Ibberson Conservation Area. The common tree species are chestnut, red, black and scarlet oak, table mountain, white, and Virginia pine, hickory, black gum, basswood, black walnut, black birch, black cherry, sassafras, black locust, red maple, and American beech. This wide variety of trees species creates a habitat for a wide variety of woodland creatures, such as the white-tailed deer, American black bear, wild turkey, grey and red squirrels, ruffed grouse and a wide variety of birds.