Great Lakes Mesoscale convective complexs or MCCs can cause damage to wide swaths of forest and shatter glass in city buildings. These storms mainly occur during the night, and the systems sometimes have small embedded tornadoes, but more often straight-line winds accompanied by intense lightning. Historically, the Great Lakes, in addition to their lake ecology, were surrounded by various forest ecoregions (except in a relatively small area of southeast Lake Michigan where savanna or prairie occasionally intruded). Logging, urbanization, and agriculture uses have changed that relationship. In the early 21st century, Lake Superior's shores are 91% forested, Lake Huron 68%, Lake Ontario
Great Lakes to regulate water supply and use. Tourism and recreation are major industries on the Great Lakes. A few small cruise ships operate on the Great Lakes including a couple of sailing ships. Sport fishing, commercial fishing, and Native American fishing represent a U.S.$4 billion a year industry with salmon, whitefish, smelt, lake trout, bass and walleye being major catches. Many other water sports are practiced on the lakes such as yachting, sea kayaking, diving, kitesurfing, powerboating, and lake surfing. The Great Lakes Circle Tour is a designated scenic road system connecting all of the Great Lakes and the Saint Lawrence