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Re: Burning of prairies

Chris: This is my first input since subscribing. I'll introduce what we are
trying to accomplish and what we recommend for fires based on our own
experiences and that of several colleagues who have been "fired" up about
prairies and savannas for many years.  We hail from central Wisconsin at
the Waupaca Field Station, where we are restoring 70 acres of sand and
shrub prairie and about 60 acres of oak savanna -barrens subtype based on
extensive historical documentation and studies of local relics.  We have
been involved in savanna and prairie research since 1982 and have mapped,
conducted diversity indices, and are seed collecting on 38 relics within
our area. Most folks don't realize that our area and the historic mixed
ecosystem of savanna and prairie extending from the St. Croix River in the
northwest and the famous portage of the Fox and Wisconsin Rivers was one of
the first areas to be described as true "prairie" by the French
missionaries, poking their noses into the lands of the Sauk, Fox, and
Winnebago people.

 Our particular site represents formerly an extensive "opening" in the
savanna landscape which measured over 12 miles long and 7 miles wide based
on Original Land Survey records.  We have visited and studied several
premier prairies, grasslands, and savannas from Manitoba south through the
Dakotas and Kansas to Oklahoma and east into Ohio over the past several
years.  We have been training our own volunteer fire crew since 1990 and
have a fully equipped fire unit on site and supplies for two 10-person
crews. Our primary goal is for completing the restoration and unifying the
present relics by the year 2000. We have been named a primary recovery site
within the Morainal Sands Region in Wisconsin for the federally endangered
Karner blue butterfly. The population within our portion of this
metapopulation has the fifth highest density in the state. We are also
trying to conserve other rare species and specific qualities of their
habitat such as the Phlox Moth, Persius Duskywing, Frosted Elfin, Regal
Fritillary, Prairie Fameflower, Wild Petunia, and even one species of our
native cacti. We are active members of the Society for Ecological
Restoration and have hosted or are presently conducting several research
projects relating directly to management techniques, including fire
regimes. Our site is
nessled within a 4.5 square mile chunk of public land where we are working
with the NBS, USFWS, and our DNR to encourage local landowners to sign on
for a landscape approach to diversity management. 

We have burning experience only on mollisols and alfisols but on several
catenas, during both wet and dry years, so believe I can provide some
specific suggestions concerning fire frequency, intensity, and coverage. As
you know, several conditions determine just the right mixture for a proper
burn, and each burn should have a particular goal, not just to remove old,
dry vegetation. Several prairie texts swear by the 2-3 year frequency but I
can not recommend that on any site I have seen due to the damage it can do
to invertebrates and the time it takes for some species to recover from
such losses. Never burn an entire site. Study it first, separtate it into
microsites based on grass and forb dominants as well as soil catenas, and
dissect it down as small as one acre or less based on the specific needs of
rare species.
Vary your burn dates as you suggested and rotate at not less than 5 years
on most subsites. More frequent burns have actually seen major shifts in
dominance and diversity, encouraged erosion on steeper slopes, and
significantly affected the success of invertebrate populations. You may
wish to refer to several papers from the past National Prairie and Savanna
Conferences, the research conducted at the Konza (they have their own web
site!), and even contact local fire crews and staff of The Nature
Conservancy in various states where their Natural Heritage Programs and
Scientific/Natural Areas are annually being burned in a mozaic. Most folks
trying to manage for both plants and animals within these ecosystems have
adopted burn rotations between 5 and 20 years or more! On our restored
sites we first burn 5 years after seeding, and mow once or twice either in
its first thru third years depending on undesireables persisting. We have
found that burning our savannas in late summer or early autumn is best to
preserve the native cool season grasses, reduce the importance of native
thick stands of Penn. sedge and remove litter accumulation from open grown
oaks. This dries the upper soil horizons and reduces the importance and
success of oak grubs and hazel, natural components in the grass understory.
We have found that the 5 year minimum rotation also works best to protect
those slow growing flowering forbs that need the overstory of dry grass to
moderate the upper soil horizons and allow the young plants to get well
established. The flower bloom following our five year burns has always been
much better than our experimental 2- and 3-year old burns.

Those folks wishing to learn more about the results of specific research in
their areas can try to link up with their local TNC staff, DNR personnel,
contact the Konza Prairie Web Site, or Contact the Northern Prairie Science
Center with the National Biological Service at:

 npsc.nbs.gov/resource/tools/burning/burning/htm         

Other current research that might be of interest on restorations of both
prairie and savanna can be contacted at: 
ies.wisc.edu/research/ies900/body3.htm
           same:                                                 /willis.htm
           same:                                                
/bradweb.htm 

I hope this helps. Thanks for the motivation to communicate back. Sincerely,
Robert J. Welch, Staff Ecologist, Waupaca Field Station
(welchr@add-inc.com)  
----------
> There have been a lot of questions about burn frequency, etc.  I'm not an
> expert in this, so if I miss something (or get it totally wrong), feel
> free to jump in.
> 
>    Burning is an important step in prairie development.  It helps give
>    warm-season grasses an edge over cool-season plants that tend to
>    be undesireable in a prairie environment.
> 
>    Studies show that prairies thrive with regular, controlled burnings
>    every 2 to 3 years.
> 
>    Ideally, the prairie should be burned sometime in the early spring.
>    If there are no early-blooming flowers, it can be burned as late as
>    mid-spring.  If these aren't possible, fall will work so long as
>    the prairie species are dormant but the non-natives are still active.
>    This alternative will harm over-wintering insects, however.
> 
> Hope this helps!
> 
> Chris
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