Fire is rare in northern floodplain forest in humid climates. However, occasionally fire probably influenced presettlement northern floodplain forests in drier climates. In a North Dakota gallery forest, the oldest trees were only 80 years old, even though the forest had been recorded in presettlement survey records. Severe fire that consumes organic layers and exposes roots kills most willows.
Fire easily kills cottonwood seedlings and saplings.
Trees less than 20 years old may sprout after fire damage. Mid- and late successional northern floodplain species such as American elm, silver maple, and boxelder are easily damaged or killed by fire, particularly when young. Controversy continues over whether northern Great Plains woodlands have expanded or declined since settlement and the beginning of fire exclusion in the late 19th century.