Chapter 4: 1-Year (2014 , 3-Year (2012–2014 ) , and 5-Year (2010–2014) Maps of Drought and Moisture Surplus for the Conterminous United StatesThis article is part of a larger document. View the larger document here.
Droughts occur in most forest ecosystems of the United States, but their frequency and intensity vary widely (Hanson and Weltzin 2000). Annual seasonal droughts are typical in Western U.S. forests. In contrast, Eastern U.S. forests usually exhibit one of two predominant drought patterns: random (i.e., occurring at any time of year) occasional droughts, as typically seen in the Appalachian Mountains and the Northeast, or frequent late-summer droughts, as observed in the Southeastern Coastal Plain and the eastern side of the Great Plains (Hanson and Weltzin 2000).