Tuesday, March 23, 2010

Great prairie burns today

The weather is finally cooperating and we were able to get in a lot of burns today. We burned the south-facing slope (about 13 acres), which is short-grass prairie remnant on the lower part and bur oak savanna above. We then burned about 9 acres of wet-mesic prairie adjacent to our wetland. The humidity was fairly low (25-30%), making it really easy to carry out these burns.

We always burn the south-facing slope carefully to keep the flame heights low. We use the strip head fire technique, which takes quite a few drip torches, but provides maximum control. We start at the top of the slope, at one end of our permanent mowed fire break, and make a wide black line to the other end. We use two or three drip torches for this. One operator ignites exactly on the fire-break line, and the second lights about 25 feet further downslope. If available, a third drip torch is about 50 feet further down. We move fairly slowly to be sure we are getting a good wide black line. The photo here shows the black-line group in action.



Once the black line is half way across the slope, another drip torch starts at the beginning about 100 feet further downslope and lights a line. This creates a head fire which cannot move uphill very far before it reaches the upper black line and goes out. Two or three more drip torches spread out below follow, each staggered so that no drip torch operator is in danger.

Today, we began lighting at 12 noon and finished the whole burn at 2 PM.

After a brief snack, we started on the wet-mesic prairies. Generally, this early in the season these prairies would still be fairly wet and would not burn well. Not this year. The low humidity weather really dried them off, and we got close to 100% burn coverage. The photo below shows the tail end of the Valley Prairie burn. You can see the already-burned south slope in the background.



We hope to do our major oak savanna burn on Thursday, March 25. Join us!

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