When the first explorers came to what became Minnesota, they found a land with three very different personalities. To the north were the great forests of white pine and other conifers that later attracted armies of lumberjacks and made Minnesota a leading producer of lumber. To the south and west was the beginning of the Great Plains, the flat, fertile prairie that was broken into successful farms. And in what is now south-central Minnesota was the dense broadleaf forest that settlers called the "Big Woods."
The Big Woods was at the western edge of the great deciduous forest that swept over the middle United States from the Atlantic coast to the Great Plains. In Minnesota the deciduous belt ran from the northwest to the southeast, thickening in the middle to form the Big Woods. There, elm, basswood, sugar maple, and red oak covered more than 3,000 square miles, rising high in the air to form a vast canopy that nearly obliterated the sun during the leafy summer months.
Fire played a large part in determining the boundaries of the Big Woods. Prairie fires, started by lightning or by Indians for hunting purposes, kept the broadleaf trees from invading the grasslands. At the same time, natural firebreaks - lakes, rivers, and rough terrain - prevented these fires from spreading into the forest itself.
Fertile soil lay beneath the Big Woods, and, inevitably, much of the land was cleared for farming during the last half of the nineteenth century. Only a few remnants of the great forest remain today. The largest of these lies east of Northfield at Nerstrand Woods State Park.