Friday, April 2, 2010

Mop-up after savanna burn


Most prescribed burns have a few mop-up elements, but savanna burns often have lots. This is because there are almost always dead logs or standing dead trees that, despite the most careful attention, catch on fire. Such large logs or trees can often burn for a long time.

We deal with these burning logs in several ways. A day or two before the prescribed burn we "fireproof" all standing dead trees by carefully clearing grass, sticks, and other flammable debris from a wide zone at the base.

If a burning log is well within the burn unit, completely surrounded by black, we let it burn. Part of the prescription in our savanna burns is the elimination of dead wood, especially logs lying on the ground. (However, we like to retain some of our standing dead trees, called snags, as wildlife habitat.)

However, if a smoldering log is too close to the edge of the burn unit, then we put it out. This is because there is always the possibility of a wind shift that might pick up embers off such a log and carry them into unburned areas, causing a spot fire.

The photo shows Kathie putting out a smoldering log that was close to the edge of the Unit 19E savanna. It was about 30 feet from the fire break, probably safe enough, but no point in taking chances. It takes a fair bit of water, and rolling the log around to reach burning areas. Our pumper units, which have high pressure water, are ideal for this, but single logs, such as the one shown here, can generally be extinguished with water from a backpack water can.

The best time to find smoldering logs is late in the day, when the weather has started to cool and humidity has begun to increase. Also at this time of day the sun is at a steep angle and when backlighted the smoke is more visible.

We toured the whole burn area around 6 PM, checking for signs of smoke. Fortunately, most of the smokers were well inside the black and would cause no problem. Just a few required attention.

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