Tom's Blog

Wednesday, April 17, 2013

Planted prairie burns

Our friendly NOAA weather site promised us a single sunny day stuck in between lots of rainy days, so we burned. Although we still have lots of savanna areas (and a wetland!) to burn, their fuel moisture would not drop as fast as those of the planted prairies. So yesterday we burned Toby, Ridge, the East Basin, and the part of the Pocket that was too snowy when we burned the rest of it on April 4.

The day dawned cold but sunny. A check of the humidity showed fairly high readings but with a promise of lower values later in the day. (My Kestrel is broken so I am using a sling psychrometer to measure R.H.) We scheduled the first burn for 1 PM and spent the morning doing other work. We had an experienced crew of 6, which was large enough for these small (all less than 5 acres) prairies.
Crew getting ready to burn Toby
 Since all of the planted prairies are fairly small, they have lots of edges, which makes them complicated. You have to burn slowly.

Toby was first planted in 1998 and is a nice prairie. When we started it was completely surrounded with an aspen clone that was gradually closing in. The aspen trees were girdled in 1998 and removed two years later. The aspen understory had remnant prairie and was enhanced by overseeding. It is now part of the prairie and it is difficult to tell where the original cropped area stopped. The principle fuel is Indian grass and little bluestem, with a high diversity of forbs.

Burning the SE corner of Toby. Kathie is making sure the fire doesn't creep into the Triangle savanna.       
 Once the edges are burned in, the main burn can proceed quickly, as the photo below shows..

Lighting the west end of Toby. By this time, the periphery was completely black so the center was burned rapidly.   
We started lighting about 1 PM and finished in an hour. The photo below shows the end result.

The end of the Toby burn. This is slightly less than 4 acres. Because of last year's drought and the winter's heavy snow, the fuel was very sparse. However, we had a good wind, which helped carry the fire.
The Ridge Prairie is less than 2 acres, but had been cropped and so was eligible for CRP back in 1987 when we first started in this program. However, it was not planted to prairie until 2005 and will be in its 8th growing season this year. It is sandwiched between an oak woods on the west and the East Basin prairie on the east. Now that the East Basin Prairie has become established, we burn these two prairies together.
Kathie monitoring the west line of the Ridge Prairie.

Since the East Basin (not part of the CRP) is now only in its 3rd growing season, the flammable fuel is still fairly spotty. However, it has quite steep topography which means that the fire moving uphill is essentially a head fire even if the wind is light. Some areas have fairly substantial Indian grass whereas other areas are principally less flammable forbs. The end result was that burn coverage was about 50-60%.

The final burn of the day was the SE corner of the Pocket Prairie. When we burned the rest of the Pocket on April 4, this area still was in snow and could not be burned. (It was shaded by the oak woods east and above.) So we burned it today. The main concern was to keep the fire out of the oak woods. Kathie had mowed a fire break between the prairie and woods, and this provided a relatively good barrier. (Although one spot fire jumped the line but was quickly put out.)
Burning the SE corner of the Pocket Prairie. The rest of this prairie, now greening up, was burned on April 4.

We finished at about 5 PM. In all, a good day. (The next day it rained hard!)

1 Comments:

Blogger Dana Lee Ling said...

Excellent photographs, amazing to see the results of seventeen some years of hard work and effort! I have only the briefest of opportunities to help care for an oak savanna, but as a runner there is nothing quite like running full tilt on trails amidst oaks on the hills of the driftless area. Keep up the great work!

April 23, 2013 at 2:41 AM  

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