USGS Grant: Upper Mississippi River Floodplain Forest Succession and Tree Survivorship

Understanding and predicting patterns of forest
succession in floodplains is difficult due to the fact
that they are strongly influenced by patterns of
disturbance, which are often stochastic in nature.
Flooding is the most common disturbance event on
floodplains and often determines the distribution of
forest species and communities with only slight changes
in elevation. The degree to which flooding influences
tree survival is a function of how different species and
size classes can tolerate differences in flood frequency,
duration, intensity, and timing. Most floodplain trees
are adapted to survive moderate frequency, moderate
intensity and short duration flooding when it occurs
during plant dormancy between late summer and early
spring. Tree mortality increases with flood frequency,
intensity, and duration or when flooding occurs during
the growing season, particularly for smaller size
classes. Infrequent, large-intensity flooding is
generally considered natural and may actually be a
driving force of species and community distribution and
development, successional patterns, and the recruitment
of new tree cohorts required for forest sustainability at
the landscape level. A recent large-scale flood
disturbance event in 2019 has provided an opportunity to
better understand how differences in major flood
attributes impact tree survivorship and resulting forest
community dynamics in the Upper Mississippi River System
(UMRS).