I returned today and did a detailed assessment of the quality of the North Woods burn that we had done on Thursday (see last post).
I used my Garmin GPS in Track mode to circumscribe the area we burned. I started at the top of the ridge, next to the North Fire Break. I followed the edge of the burn down hill all the way to County F, then continued east, following the direction that the drip torches had taken. Except that not everything the drip torches touched carried fire, so there were significant jumps. So I spent about two hours climbing up and down hill, following the burn line, and all the while moving east toward the edge of the unit. I ended up almost to the top of the ridge once, and then plunged back down toward the bottom. This jagged fire line was made because there were areas in the woods that were almost devoid of trees, so there was no oak leaf fuel.
I did see lots of areas where brambles and honeysuckles were top killed by the fire, which is one of the goals of this sort of burn.
I finally got to the end of the burn unit at the top of the ridge (just west of Toby's Prairie) and then walked back along the North Fire Break to my point of beginning. The walk along this fire break was interesting, because up at the top of the ridge there were lots of brambles and buckthorn that were top killed. Next spring we will be revisiting these areas and herbiciding the new sprouts that will be coming from the dead stems. This will be easy work because the burn really cleared out the area, so we will have good access for spraying.
At the end the GPS told me that I had circumscribed 15.3 acres. These were the areas that had burned essentially completely. Since the whole burn area was about 25 acres, the average coverage was 61%. This would not be good for a prairie burn but is great for a woods burn. The irregularities of the terrain and the heterogeneity of the vegetation are responsible for these differences.
In addition to assessing the quality of the burn, I also got to see a few really nice wooded areas that I was unaware of. There was one rather open area with a lot of medium-sized white oaks that I had never noticed. Usually when walking in this woods I keep to the trail, since clambering over blowdowns and dead trunks is a little tiring.
Eventually I will get the GPS track data into ArcGIS so that I can relate the burn better to the surrounding vegetation, using the tree database we have created. One thing always leads to another, which is what makes this sort of work so interesting!
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