Wednesday, December 23, 2015

Oak woodland burns: a recent webinar

There are three fire consortiums (funded by USFS) that offer educational programs (mainly webinars) of interest to Midwest restoration ecologists. The recentwebinar presented by Greg Nowacki dealing with oak ecosystems was especially interesting. For those who missed the live presentation, the Tallgrass Prairie and Oak Savanna Fire Consortium has just posted an archive version. This version is more than a Power Point, because it allowed for questions from the audience (and answers). Some notworthy scientists were in the audience, including Roger Anderson of Illinois, one of the stalwarts of prairie/savanna ecology.

I usually try to watch these live presentations, but had to miss the one on Oct. 15 2015. Yesterday I watched it.  Here is the link. 

There is an advantage to watching an archived version that the live version lacks: you can stop the presentation at any time, go back and hear something again, and skip boring parts. (However, there were no boring parts to Greg Nowacki's presentation!)

Michael Valhdieck photo 10-29-2014
Among other things, Nowacki had a very clear presentation of why oak ecosystems are fire dependent.

As the photo from our Oct. 29, 2014 burn shows, oaks have thick leaves that fall dry and stay dry. (Double-click to enlarge the photo for better viewing.) They are very rigid and curl up on the forest floor, providing better aeration for burns. Thus oak leaves "carry" a fire very well, providing an excellent fuel bed for a fire.

In the 2014 burn, once the black line had been ringed all the way around the woods, we had a number of people with drip torches doing interior lighting. The fire lines show clearly in this photo, and within  moments after it was taken, the fire lines coalesced.

It took our crew of 19 only 2.5 hours to burn this 30 acre woods. Also, there was little mop-up, since this woods had been burned 5 times in the last 10 years.

Other aspects of the fuel characteristics of oak forests that Nowacki discussed: The coarse woody debris from oak logs decays slowly compared with maples and other mesophytic tree species, assuring a build up of woody fuel on the ground.

Nowacki also noted that wildlife has coevolved with oak, so that an oak forest is much more beneficial for wildlife than other hardwood forests. Acorns provide an outstanding food value for wildlife ("the ecological equivalent of manna from heaven").  Two days after the Oct. 29 burn, eight deer were seen in our woods, with their heads down eating "roasted" acorns! The year 2014 had been a good "mast year" for red oaks, the principal species in this woods.

(In case the link above does not work, I have copied the URL below. Don't miss this outstanding presentation!)

http://www.tposfirescience.org/webinars/archived-webinar-past-fire-and-present-day-mesophication-imp.html

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