After a very cold March and major snow drifts, things finally warmed up a bit and we were able to do some major burns. The weather was cold but clear all week, but on Thursday it promised to be warmer, with 35% R.H. and 10-15 mph winds. Although the wind gave us trouble with spot fires, it also helped carry the fire.
|The burn crew assembled at the cabin to review the burn plans|
Because we had a large crew (20 people), we did two separate burns at the same time: 1. The south-slope burn; 2. The basin savanna burn. The map here shows what we burned.
|The burns of 4 April. (The colors have no meaning.) The south-slope burn is Units 1-7. |
The basin savanna burn is the rest. The East Overlook was the dividing line.
1. South slope. Last summer's drought had a major effect on the grass growth on the south-facing slope. Instead of knee-high, little bluestem was ankle-high. We had never seen the prairie sod so impoverished. We still used the strip headfire technique, but instead of using four or five strips, we only used two. As usual, this burn began with creating a wide blackline at the top of the hill. This involved two drip torches plus lots of water because of spot fires elicited by the strong wind. This was the most time-consuming part of the whole burn. Once the blackline was in, a drip torch ran a strip across the middle of the slope. Once that was in, the final drip torch lighted from the bottom of the slope, at Pleasant Valley Road.
|Burning in the blackline at the top of the south-facing slope. The widening line can be seen in the distance.|
|Finishing the burn on the White Oak Savanna (Unit 12A)|
2. Basin savanna. The basin had lost its snow about a week ago and although the grasses and forbs had also been affected by the drought, the oak leaves had not, and these were a major part of the fuel. We started lighting Unit 12A at the far NE end of the savanna. One drip torch went parallel to the top and the other went down the hill (above the ravine). The burn boss coordinated the two drip torches, making sure that the upper one was well ahead of the one near the ravine. Once the 12A blackline at the top was burned in, the second drip torch lighted from below. This procedure continued through Unit 11D and 18, until the East Overlook was reached. After the whole savanna was on fire, the Pocket Prairie was burned, mainly as a headfire.
We started lighting at 11:45 AM and finished at 2:45 PM. Because of the wind, we had the potential for lots of spot fires, so moved fairly slowly. All of the personnel were experienced burners. We had enough radios so that each person could have one. Each burn was run on a separate channel. Kathie, who operated the water supply from our Kawaski Mule, had two radios, one on each channel.
After a short lunch, we burned all of the planted prairies south of (below) Pleasant Valley Road: Valley, Barn, and Cabin.
Then most of the crew moved to Black Earth Rettenmund Prairie to carry out an early-evening burn. Since the wind was still holding, this burn moved very fast (30 minutes for the whole burn).
In all, a great day!
Two days later Kathie and I surveyed the burn areas and made notes on burn coverage. Much of the area had virtually 100% coverage, although there were a fair number of unburned areas on the uphill part of Unit 11D. probably because of patchy fuel.
|Upper part of the south-slope, with good burn coverage. This is primarily bur oak savanna.|
|The basin savanna burn. Unit 12A in front and 11D behind. Pocket Prairie at the bottom. The trees are white oaks.|