Another big (final?) burn day

Yesterday (29 March 2012) we did our last burn for the year at Pleasant Valley Conservancy (PVC). Hard to believe, since in 2011 we did our first burn of the year on 30 March. Yes, the weather has been warm. And yes, it has presented challenges for any burn program. But our philosophy has always been to get ready for burns well ahead of time and when conditions are ripe, burn. (And do big burns.)

Yesterday, we burned 12 savanna units (30 acres), two prairies (Ridge and East Basin), and three oak woodland areas (Units 13, 20, and 21). We then finished off the day by doing the 2012 prairie burn at Black Earth Rettenmund. A long day. (We got home well after dark!)

We had a great crew (11 people), all very experienced burners who were all familiar with the habitats and terrain at the two sites. These are both high quality State Natural Areas and well worth careful attention.

The oak savannas we burned at PVC are what we call the "Ridge-top Savannas". These differ considerably from the South-slope Savannas that we burned on March 13, and the long-narrow savanna that we burned on March 15. Because these other two savannas had been burned, the Ridge-top Savannas were completely surrounded by blackline and hence we had no worries about containing the fire.

This burn season the fuel in our savannas is very lush, so there is no problem getting them to burn. However, lush fuel is conducive to very flashy burns, with high flame heights that are undesirable because they set high branches of the oaks on fire and do havoc to the snags. So for yesterday's burn, a backburn was used for the whole burn.

The area we burned is 0.6 mile long and has a complicated layout. (Because of the distances involved, we could not have done this burn without two-way radios.)

To accomplish the backburn while keeping the burning time within reason, we used the strip headfire technique. Four drip torches operated in parallel, about 100 feet apart. This ensured that any incipient headfire quickly ran into a parallel backfire and collapsed. Once started, the drip torches moved continuously until they reached the far end (where another crew had already established a black line).

Four "waters" plus a pumper unit on a Kawasaki Mule took care of any problems that arose.

Once the strips had been laid down, we could mostly wait for the backburn to reach the end of each unit. In a few areas, interior lighting was necessary, and to speed up the final process a narrow headfire was laid down at the bottom to complete the burn.

After a brief lunch, we did the rest of the burns at Pleasant Valley Conservancy and then moved to Black Earth Rettenmund Prairie for a late afternoon burn.

An oddity. Halfway through our big savanna burn I heard a voice on my two-way radio calling Ken. We had no one on our burn crew with that name, but there is a Ken who manages another Prairie Enthusiasts (TPE) site (Pleasure Valley Conservancy; note the name difference) about 5 highway miles away. Obviously another TPE burn was in progress, operating on the same frequency we were.

The weather yesterday was great for burns. According to Scott, the DNR forest ranger who stopped by at our burn, there were 35 burns going on in his district! It's encouraging to know that so much prescribed burn activity is going on in southern Wisconsin.

This warm weather! Too late to burn?

Lots of prairie plants are already up but it is not too late to burn.

Early species such as golden Alexanders, shooting star, pasque flower, prairie smoke, pussy toes, and violets, will certainly be set back, but their roots and underground dormant buds should survive burns undamaged just as they survive grazing.

Despite the green, the fuel from last year is still there, and should carry a fire well, given regular burn conditions. The main problem caused by the excess green will be smoke management, so that careful attention to wind direction and air mixing height may be necessary where highways or residential areas intrude on burns.

Most of the green visible in prairies now is due to nonnative grasses such as smooth brome or bluegrass, which are undesirable anyway.

Burns are so important in prairie and savanna management that they must be done even if early floral displays are affected. Without burns, shrubs both native (brambles, sumac) and nonnative (buckthorn, honeysuckle) will get a head start and will either require expensive brush control work later or will make it more difficult to burn next year. One should never let shrubs get a head start, especially in recently restored prairies or savannas.

The photo shows golden Alexanders and zig-zag goldenrod, already up on March 23, about three weeks earlier than previous years.

Although long-range weather prediction is difficult, it seems likely that this unusual warm spell will be followed by at least one or more hard freezes. Don't put away your long underwear yet!

Protecting lady slipper orchid site for burn

Although most of our yellow lady slipper orchids are in the north woods, one of the best stands is in the Unit 8 savanna. Probably because it is a savanna site, it blooms earlier, and the plants are quite lush. In fact, one of Kathie's photos from this site was selected for the Military Ridge Prairie Heritage calendar last year. (Kathie's photo here is not the calendar image. I chose this one because it shows such a nice stand of Zizia aureus in the background.)

Because of the unusually warm weather, Kathie was worried that this stand would get damaged by the savanna burn we hope to do this next week, so she spent some time clearing around it. Although this is indeed micromanaging, for such a spectacular species it is worth it.
Lady slipper orchids have flowered annually at this site for at least 10 years, ever since we cleared it and first burned. However, this is the first year we have protected it from burns (and the first year we have had such a lengthy warm spell).

The site itself is interesting, since the plant it is just uphill of a dolomite outcrop, and there is barely any soil.

Protecting birch trees for prescribed burns

One can argue whether any tree species should be protected from fire during prescribed burns. If the point of burning is to restore the landscape to its original condition, then fire-sensitive trees should not be part of it. However, birches are handsome trees, and provide excellent nesting sites for red-headed woodpeckers, so perhaps saving at least a few is not such a bad idea.

We also clear around standing dead trees (snags), since these make excellent wildlife habitat. Dead snags are very fire-sensitive, and if not cleared around will generally catch on fire. A burning snag presents a potential mop-up problem, especially is it is tall and is close to the edge of the burn unit.

Our procedure for saving snags and birches is to use a powerful leaf blower to clear the leaves and other fuel away. It takes only a minute to clear a tree, so one can take care of a whole burn unit in an hour or so.

How effective is this?

I returned two days later to the Unit 19 savanna that we had burned to see how the trees survived. The photo here shows a typical result. The bark looks completely unscorched, which is gratifying. (Our work was not wasted.)

One downside of clearing around trees is that buckthorn or other undesirable woody plants can find a refuge and escape being top-killed. A special effort has to be made to find them and kill them with herbicide.

Post-burn early reed canary spraying

One advantage of getting burns done this early is that one can get ahead of the bad guys and improve chances for early spraying. The photo shows a small patch of reed canary grass we found 5 days after our wetland burn. I sprayed it with 4% glyphosate.

This patch had already started growing before the burn, but was mixed in with a lot of heavy dead thatch, making it difficult to spray. After the burn, with all the thatch gone, it was easy to find and easy to spray.

This time of year I prefer to spray with glyphosate, as it is a general, nonspecific herbicide that will kill anything. Also, it is inactivated by soil particles so there is no residual activity.

According to the co-op, the ideal time to spray with glyphosate is when the leaves are 4 inches long, which is just about where that reed canary patch was when I sprayed it.

There are lots of other species that are coming up now and can be sprayed when ready. On my list are day lilies, smooth brome, motherwort, and perhaps garlic mustard. This time of year, almost anything green is bad. The rule with glyphosate is if it is green you will kill it.

It is unusual to be able to burn this early in the season, but an alternative is a late fall burn. We did just that in the Crane Prairie, and will be in there soon looking for bad guys.

I'll be back in a week or so checking on that sprayed reed canary patch. Almost certainly I missed some leaves, and new shoots might be coming up from underground rhizomes outside the growth circle.

First savanna burn of 2012

We are really jumping the gun this year on burns, taking advantage of the early favorable burn weather. One of our most important burns to be done is the ridge-top savanna burn, but before we do that we needed to burn the long narrow strip of savanna and open oak woodland that separates the ridge-top savanna from the north woods (Units 19A through 19E). In the past few years we have been burning Unit 19 first to avoid spot fires that could develop when we burn the big savanna.

Thursday, March 15 promised to be another warm day, but it started out very foggy, and all the fuel was dripping wet. However, by lunch time things had dried out and conditions were good for a savanna/woodland burn. We had our regular crew enhanced by Jim Hess. All were experienced and in fact had burned this same unit the past three years.

Unit 19 is an accident of geography, since it is separated by our gravel service road from the rest of the ridge-top savanna. It mostly slopes downhill toward the north. We have a good fire break north of Unit 19 and just uphill from the large north woods which drops steeply down toward the county highway. Thus, Unit 19 is a long, narrow unit, about 5 acres. There are quite a few birches, which had been cleared around since we wanted to save them, but we still had quite a few potential "torches". The pumper unit in our Kawasaki Mule got a great workout.

There was a light wind out of the west and north, not enough to prevent us from burning, but enough to contribute to the head fire resulting from the slope. Thus, we we had to burn slowly. One drip torch backburned down from the gravel road toward the north and once a good strip had been blackened the second drip torch lighted uphill and upwind. The photo below shows the start of the burn, which is in the wider area called 19E. The gravel road that we backburned down from is shown, and the north fire break is in the back, about 25 feet from the flaming front. The second photo shows this same area from above after the fire had passed through. This is a nice area of predominantly white oaks.


The backburn along the gravel road went well, except for the birches, but the burn uphill from the N fire break led to flame heights that caused quite a few problems. We put out most of the flaming birches, and one or two tall snags.

The photo below shows the line crew moving along the north fire break. We tried to keep the flame heights as low as shown here. In addition to backpack water, we kept the pumper unit mostly on this fire break. (The Kawasaki is great because it can go anywhere in this kind of terrain!)

One problem was the large area of dead black oaks that (suffering from oak wilt) had been decimated by a strong linear wind about four years ago. Although the trunks were still standing, the tops had been twisted off. Although great trees for critters, they are bad for burns. Short stumps that were well inside the burn unit were allowed to burn, but tall snags had to be put out. The photo here show Kathie working on a typical snag.

We took care of most of our problems as we burned, so there was not much mop-up.




After the burn was finished I found a small snake curled up on top of black ashes. At first I thought he had been cooked, but he looked too clean and neat. When Amanda poked him with a stick, he started moving, and was in good shape. He had obviously moved onto the black from the unburned area across the road. I've seen large numbers of red-winged blackbirds move into a recently burned area, but never a snake. Maybe he likes the warmth?

Just as we finished the burn Paul Zedler's class in fire ecology (UW-Madison) turned up. Good timing!

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.

First big burn of 2012

Yesterday (March 13, 2012) we spent all day doing burns. The weather cooperated, we had a great crew, and we got a lot done.

The fuel this spring is very heavy, guaranteeing quite "flashy" burns, so we had to alter our usual burn procedures. There are two reasons for the flashy fuel: 1) last year the growing conditions for prairie grass was very favorable; 2) there was no significant snow this past winter, so that the grasses did not get compressed as they usually do. Because of this condition, we did several passes with the Kubota at the edges of the fire breaks to reduce the tall grass and widen the breaks. The photo here (the Pocket Prairie ) shows how lush the grass was.

The morning of the first burn of the year is occupied with getting things ready. We had to install the pumper unit in the Kawasaki Mule, start our well, fill the pumper unit, fill all the backpack water cans and jugs, get all the water distributed, do a final "touch-up" of the fire breaks with leaf blowers, fill all the drip torches, etc. We weren't ready to burn until about 10:30 AM.

This delay was no problem because when we arrived at 9 AM the vegetation was pretty wet. However, the day was clear and a steady sun was in the forecast and we anticipated good burning conditions.

Although our main goal was to burn the whole south slope (prairie and bur oak savanna), we first burned two planted prairies, Toby's and Pocket, to get these very lush prairies out of the way. Because these burns were fairly straightforward, we split our crew and burned both prairies at the same time. The photo below shows the middle of the Pocket Prairie burn.

After a half-hour lunch break:
most of the crew climbed in the truck for the ride to the top of the ridge, with others catching rides in the two Kawasakis. By the time we reached the point of ignition the humidity was down in the 30s and the vegetation was nicely dry. The wind was out of the west at about 5 mph.

We have had a lot of experience over the past 15 years burning the south slope and our burn procedure has by now been well refined. I discussed in detail our fire breaks in a recent post.

Yesterday we started in the middle of the south slope, behind the Rocky Overlook, with two burn lines moving in opposite directions away from that point. The photo here shows Amanda in an early stage of this backburn. The newly created blackline can be seen in the background.

Once the initial blackline was established, a second drip torch on each burn line ran another strip about 50 feet below. These two lines quickly coalesced, creating an ever widening backburn that moved down the hill, as the photo below shows.
We also had another drip torch creating a further line below which we used only sparingly.

Everyone on the burn was kept informed of what was happening by two-way radio (we use Kenwoods). Although these radios are expensive, they are very essential on a burn such as this, because most people are out of sight of each other.

The south-slope burn (14 acres as measured by GIS) was finished at about 2:30 PM. Mop-up, which is often a major part of a savanna burn, was fortunately minimal. There was one tall dead snag that was smoking badly and had to be cut down. Any smoker that was fairly short and was well inside the burn unit was allowed to burn. A couple of crew members stayed on the burn to monitor problems, and the rest of us went down the ridge and got ready to do the wetland burn, which will be the topic of another post.