Tom's Blog

Saturday, March 17, 2012

First savanna burn of 2012

We are really jumping the gun this year on burns, taking advantage of the early favorable burn weather. One of our most important burns to be done is the ridge-top savanna burn, but before we do that we needed to burn the long narrow strip of savanna and open oak woodland that separates the ridge-top savanna from the north woods (Units 19A through 19E). In the past few years we have been burning Unit 19 first to avoid spot fires that could develop when we burn the big savanna.

Thursday, March 15 promised to be another warm day, but it started out very foggy, and all the fuel was dripping wet. However, by lunch time things had dried out and conditions were good for a savanna/woodland burn. We had our regular crew enhanced by Jim Hess. All were experienced and in fact had burned this same unit the past three years.

Unit 19 is an accident of geography, since it is separated by our gravel service road from the rest of the ridge-top savanna. It mostly slopes downhill toward the north. We have a good fire break north of Unit 19 and just uphill from the large north woods which drops steeply down toward the county highway. Thus, Unit 19 is a long, narrow unit, about 5 acres. There are quite a few birches, which had been cleared around since we wanted to save them, but we still had quite a few potential "torches". The pumper unit in our Kawasaki Mule got a great workout.

There was a light wind out of the west and north, not enough to prevent us from burning, but enough to contribute to the head fire resulting from the slope. Thus, we we had to burn slowly. One drip torch backburned down from the gravel road toward the north and once a good strip had been blackened the second drip torch lighted uphill and upwind. The photo below shows the start of the burn, which is in the wider area called 19E. The gravel road that we backburned down from is shown, and the north fire break is in the back, about 25 feet from the flaming front. The second photo shows this same area from above after the fire had passed through. This is a nice area of predominantly white oaks.

The backburn along the gravel road went well, except for the birches, but the burn uphill from the N fire break led to flame heights that caused quite a few problems. We put out most of the flaming birches, and one or two tall snags.

The photo below shows the line crew moving along the north fire break. We tried to keep the flame heights as low as shown here. In addition to backpack water, we kept the pumper unit mostly on this fire break. (The Kawasaki is great because it can go anywhere in this kind of terrain!)

One problem was the large area of dead black oaks that (suffering from oak wilt) had been decimated by a strong linear wind about four years ago. Although the trunks were still standing, the tops had been twisted off. Although great trees for critters, they are bad for burns. Short stumps that were well inside the burn unit were allowed to burn, but tall snags had to be put out. The photo here show Kathie working on a typical snag.

We took care of most of our problems as we burned, so there was not much mop-up.

After the burn was finished I found a small snake curled up on top of black ashes. At first I thought he had been cooked, but he looked too clean and neat. When Amanda poked him with a stick, he started moving, and was in good shape. He had obviously moved onto the black from the unburned area across the road. I've seen large numbers of red-winged blackbirds move into a recently burned area, but never a snake. Maybe he likes the warmth?

Just as we finished the burn Paul Zedler's class in fire ecology (UW-Madison) turned up. Good timing!


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