Tom's Blog

Wednesday, March 14, 2012

Interesting wetland burn

At Pleasant Valley Conservancy we have a fine piece of a fairly large wetland, and it is in very good shape. Reed canary grass, the bane of most wetlands, is sparse and is being kept under control by judicious spraying. The whole wetland has been burned a couple of times by the Private Lands Office of the U.S. Fish & Wildlife Service, but not often enough (the last burn was 2010). Although people are often nervous about burning wetlands, after watching the F&WS folks I did not see why. The main thing was to have good fire breaks and a large enough crew. Yesterday, we had the crew and were able to get the burn done.

Our wetland is a mixture of sedge meadow, cattail marsh, and spring-fed creeklets. Most of this water drains into a substantial spring-fed creek. The wetland is riddled with tiny potholes, many of which remain ice-free all winter, showing that they are part of an underground flowage. The upwelling groundwater is fed by our ridge-top savanna, the water percolating down through the sandstone layers.

Our part of this wetland is essentially a long, narrow strip sandwiched between three wet-mesic prairies (Crane, Barn, and Valley) and the creek. There are areas of Carex trichocarpa (a clone former with deep rhizomes), tussock sedge, cattails, open water, and scattered willows. The area is fairly wide at the east end, narrowing to a strip about six feet wide toward the west end. It was the wide east end that we burned.

A main concern of the burn was to make a firebreak. Last week when we made it, the wetland was still frozen, giving us a good footing, but it was much too lumpy to mow with the Kubota. Two brush cutters were used followed by a leaf blower. This worked quite well, and I was even able to drive on the break with the Kawasaki Mule. The area to be burned was about 3 acres, as measured by GIS.
There were eight people on the burn, two drip torches and the rest with backpack water cans. The burn started at the east end, near a large willow that was not part of the burn unit. The wind was out of the southwest at about 5 mph, blowing toward the Valley Prairie and the south slope, both of which has been burned earlier in the day. Thus, the whole wetland was burned as a head fire, which quickly went out when it reached the already burned black.

Although the large cattail marsh was outside the burn unit, there were several small areas of cattails surrounded by sedge meadow, and these burned. With their dry wide hollow leaves, cattails burn very hot, and while I was taking photos I could feel lots of heat.
The whole burn took about 30 minutes.

The main area that we burned contains a very large population of Turk's cap lilies (Lilium michiganense), as well as swamp thistle (Cirsium muticum), swamp milkweed (Asclepias incarnata), and other nice wetland plants.

I am pleased that we were able to burn this wetland so expeditiously and look forward to expanding the burn area for future years, now that we have the procedure worked out.

Follow this link for details on other burns that we did on Tuesday.


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