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.