sentences:  In post-glacial times Northeastern Minnesota was covered by forest broken only by these interconnected lakes and wetlands.Much of the area has been little changed by human activity, as there are substantial forest and wilderness preserves, most notably the Boundary Waters Canoe Area and Voyageurs National Park.In the remainder of the region, lakes provide recreation, forests are managed for pulpwood, and the underlying bedrock is mined for valuable ores deposited in Precambrian times.