Visitors to Sielbeck Forest are passing through bottomland hardwood forest and a forested swamp that mirrors the wilderness documented by public land surveyors back in 1807. This island of somber grey timber was once part of the Big Black Slough, a wetland-rich floodplain that in days gone by covered thousands of acres in Massac, Pope and Johnson counties in southern Illinois. Today, nearly all of this part of the Ohio River floodplain has been drained, cleared and tiled to feed a world hungry for corn, wheat and soybeans. Despite the insatiable appetite of plow, ax and saw, this tract of land remains largely undisturbed. How did this chunk of forest persist when nearly all the trees around it fell?