In the nineteenth century, the St. Croix River valley's sandy loam soil supported forests of white pine, many of them two to three hundred years old, four to five feet in diameter, and up to two hundred feet tall. Strong, lightweight, resistant to decay from pests and rot, and easy to cut, these trees supplied the growing Midwest with abundant, inexpensive lumber for shelter, furniture, fences, and many other uses. Under the Woodland Stewardship Plan 2000, a partnership of the Minnesota Historical Society, the City of Marine on St. Croix, and the Forestry Division of the Minnesota Department of Natural Resources, work began in the winter of 2001 to restore the site to its likely appearance before the first sawmill was built by removing non-native trees such as European buckthorn and black locust and replacing them with native species such as white pine and sugar maple.