Flood Tolerance   Lee E. Frelich
  Jun 23, 2006 12:24 PDT 


I don't have an exact list, and tolerance is context dependent, depending
on mineralogy of the soil (CaCO3 content), and rate of ground water flow.
This is my best guess for common species:

In southern MN: cottonwood > silver maple > green ash > American elm = red
elm > red maple = swamp white oak = bur oak > hackberry = basswood

In northern MN: Black spruce> tamarack > white cedar = black ash > balsam
poplar = white pine = red maple = balsam fir = white spruce =hemlock
=yellow birch = paper birch = quaking aspen



   In terms of flooding tolerance and longtime deprivation of oxygen to
roots, do you have a order of tolerance listing (ya know I gotta have
lists) for species in the upper Mid-west? We've talked before
specifically about silver maples and cottonwoods in this context, but
only lightly touched on other species. I wonder what mechanism the tree
uses to compensate for lack of oxygen availability to the root system.
It isn't as if species like cottonwood and silver maple shut down

Re: Question to Lee    brown_-@colstate.edu
   Jun 23, 2006 11:43 PDT 

In terms of southeastern species, here is the abstract and ref. for a
relevant paper from a project I am involved with in eastern NC.

Roger Brown

Relationships between vegetation patterns and hydroperiod on the
Roanoke River floodplain, North Carolina
Philip A. Townsend1

Plant Ecology
Publisher: Springer Netherlands
Issue: Volume 156, Number 1
Date: September 2001
Pages: 43 - 58

(1) Center for Environmental Science, Appalachian Laboratory,
University of Maryland, 301 Braddock Road, Frostburg, MD 21532-2307,

Abstract This study quantified relationships between forest
composition and flooding gradients on the Roanoke River floodplain,
North Carolina. Because flooding is highly variable in time and space,
the research was designed to determine the specific hydrological
parameters that control woody species abundance on the landscape
scale. I specifically tested the importance of spring vs. yearly flood
duration, as well as flood duration during hydrologically wet vs. dry
years. Field vegetation samples of woody species composition were
integrated with spatial data from a Landsat Thematic Mapper (TM)
classification and a flood simulation model derived in part from
synthetic aperture radar (SAR) imagery. Flood simulations were output
and summarized for the periods 19121950 (before dams were constructed
on the river) and 19651996 (after all of the dams were completed).
Tenth percentile (dry), median, and 90th percentile (wet) hydroperiod
(flood duration) regimes were generated for the spring and year, both
pre- and post-dam. Detrended correspondence analysis (DCA) was used to
ordinate the plot data, and correlation/regression between ordination
axis scores and the flood variables were used to explore the
relationships between flooding and species composition. Nineteenth
percentile hydroperiod (i.e., wet conditions) correlated most strongly
with DCA axis 1 (r>0.9), indicating that inundation during extremely
wet years strongly controls species composition on the floodplain. The
results were used to quantitatively determine the niche width for both
species and mapped vegetation classes in terms of number of days
flooded annually and during the spring growth period. The results
suggest that spring hydroperiod is an important mechanism that may
drive competitive sorting along the flooding gradient, especially
during the early years of succession (i.e., pre-dam, which represents
the period during which most of the forests sampled were established),
and that annual hydroperiod affects the relative dominance of species
as the forests mature.

Back to Roger Brown   Robert Leverett
  Jun 23, 2006 12:30 PDT 

   If I interpret the abstract correctly, I would conclude that strong
flooding events set the vegetative regeneration pattern by favoring the
species that can tolerate the extreme events. So if an area periodically
floods in the spring, with some flooding being intensive, we would
expect to see those species dominate that can tolerate extreme episodic
conditions. Take away the extreme conditions and the vegetative
composition changes toward a greater mix. That correlates with what the
eye sees. It sounds like you are quantifying the impacts of the cycles.
Interesting area of research.

   Have you been surprised by anything that you've teased from the data
and analysis?

Re: Back to Roger Brown   brown_-@colstate.edu
  Jun 24, 2006 10:53 PDT 


That was preliminary research involved in quantifying vegetation
response to hydroperiod that can be used to model changing vegetation
conditions to hydrologic and geomorphic dynamics. The project is
attempting to develop management plans for the Roanoke Basin by
incorporating prehistoric and historic vegetation response to
hydroperiod, substrate and geomorphology, coupled with the historic
input of sediment. We have several hundred data points of current
vegetation, historic sediment depth (> 15 m in places) and reconstructed
vegetation (from pollen analysis), as well as other data such as current
erosion and deposition rates.
The Roanoke basin is perhaps the largest and relatively intact lowland
/floodplain ecosystem on the Atlantic Coastal Plain and has no dams or
larger cities below the Fall Line. The project involves a high degree of
interaction and cooperation between the researchers, the USGS and other
agencies, state agencies, the Nature Conservancy and private landowners.
The ultimate goal is to continue cooperative management of the basin,
incorporating the realities of flow management by hydropower dams
upriver and the effects of the distribution of sediment and future
remobilization of sediment on the hydrologic and geomorphic character of
the floodplain and effect on the floodplain ecosystems.

We are currently compiling all the data and developing papers - there
have been several presentations at various meetings by me and the PIs
but to date no papers published directly on the data generated by the
current project. I was a post-doc on the project and was involved with
the sediment collection and pollen analysis.
The data shows that current trends are towards forest composition of
more intermediate flooding tolerances although levee aggradation in some
areas actually results in extended hyroperiods in local areas.

For ENTS interest, there are apparently soma areas of untimbered areas
in the floodplain, including several several very large and old
cypresses. There is also an area (recently acquired by the Nature
Conservancy) that has a stand of very large Sweetgum.

Roger Brown
Re: Back to Roger Brown   Don Bertolette
  Jun 25, 2006 09:42 PDT 


Analogously, the Eastern Seaboard, at various places has a cyclic wind event
history, and local periodicity often has a strong influence which species
are "allowed" to dominate the affected stands.