Tom's Blog

Monday, March 23, 2015

Great timing: Wet snow after a prairie burn!

What's good for a prairie? A big wet snow right after a burn!

A big wet snow brings down lots of moisture but causes no soil erosion. As the snow melts, the water slowly seeps into the ground. Ideal, this time of year, just before early spring warm-up.

We are especially blessed this  year because we got almost all of our prairie burns finished just a few days ago. Great timing. Pure luck!

A big wet snow is not too uncommon in southern Wisconsin. Sometimes it's a record snow, such as April 8-9, 1973 (the night my daughter was born), when  Madison got 13 inches of very heavy snow.
Such late snows are sometimes called the "farmer's friend", for obvious reasons.

Saturday, March 21, 2015

Early-bird burn season (spring 2015)!!

It's hard to believe that the very cold February and early March changed into a perfect season for early spring burns. As the map shows, we almost completed our planned burns over 2 days in mid March. We owe this to the diligence of Amanda, who organized the whole show. (Kathie and I were mostly only spectators this year.) Although we're not quite done with burns, we only have a couple of relatively small burns left (as well as the important burn at Black Earth Rettenmund Prairie).

The two major burns shown on the map, 27 and 46 acres, add up to 73 acres. Adding the big woods burn we did on October 29, 2014, we have burned over 100 acres of Pleasant Valley Conservancy during the 2014-1015 dormant season.

We made considerable effort this year to avoid damage to the trees, especially the oaks. All of the burns were carried out as backing or flanking fires. This was especially important because this year the fuel was very lush, and hence quite flammable. It takes longer to get backburns burns done, but because our fuel was good, the fire carried well and flame heights were low and relatively benign.

Back burning the South Slope through the bur oak savanna and
little bluestem prairie remnant. At this point the burn is almost complete.
Note that the burn coverage is almost 100%.  Slapnick photo

Careful burn along the east fire break. This was the only part of the fire break that was hand-mowed. The fuel here is primarily warm-season prairie grasses. Slapnick photo
The dates when we have been able to do spring burns in our area have varied widely from year to year. The earliest we have burned the South Slope was 13 March, and the latest was early April. Last year we burned on 30 March 2014, and this year it was 17 March.

The key to a successful burn season is to plan well ahead and have everything ready when conditions are right. The two major factors are weather and crew availability.

This year we hired a professional fire weather meteorologist to keep on top of the weather and tell us when a period of good, dry weather would be availability. This worked very well, although we lost one great burn day because Wisconsin DNR canceled burns statewide, in the areas under their control.

Wednesday, March 11, 2015

Protecting prairie remnants with adjacent planted prairies

This interesting research was carried out at Nature Conservancy natural areas in four States: Loess Hills (Iowa); Glacial Ridge (Minnesota); Nachusa Grasslands (Illinois); and Kankakee Sands (Indiana). In all of these sites, prairie remnants existed embedded within extensive cropland that had been partly planted to prairie. Thus, remnant--restoration pairs existed, permitting a quantitative measure of impact of the planted prairie on the adjacent native prairie. The hypothesis was that resistance to invasion and the richness of the native flora would be greatest next to prairie restorations (planted prairies). Adjacent cropland, and roadsides would be progressively less effective or ineffective in protecting adjacent remnants.

The experimental design involved laying transects from the edges of the prairies to the center, and sampling at defined intervals.

It was found that nonnative dominance was higher at the edges than in the interiors of prairies adjacent to crops and to roadsides, whereas in prairies adjacent to restorations there was no edge effect on nonnative cover (see Figure).
Nonnative dominance from the edge to the center of prairie
remnants for different types of adjacent vegetation.

The implications of this study are clear. Prairie remnants standing alone or adjacent to roadsides or crop fields have much greater chance for invasion by nonnative species. Adjacent restorations can protect remnants against invasion.

Many prairie remnants are adjacent to ag fields which are suitable for planting to prairie. Since planting prairies is a relatively inexpensive activity, these data provide strong encouragement to carry out such plantings.

A further point: when prairie remnants are being acquired as part of land acquisition programs, high priority should be given to sites with extensive adjacent cropland or old fields suitable for prairie planting.

Here is the citation of this paper: Rowe, Helen; Fargione, Joseph; Holland, Jeffrey D. 2013. Prairie Restorations can Protect Remnant Tallgrass Prairie Plant Communities. American Midland Naturalist Vol. 170 (1): 26-38.
A prairie remnant (Black Earth Rettenmund Prairie) surrounded by ag fields and roads. An undesirable long-term situation?

Friday, February 20, 2015

Report on the 2015 Midwest Fire Conference

Just returned from Dubuque where Kathie and I attended the 2015 Midwest Fire Conference: "Keeping Fire Working for the Land". This was organized by the Tallgrass Prairie and Oak Savanna Fire Consortium (TPOS) and was a multi-state affair, with over 330 attendees and 60 speakers. Naturally, Iowa was the state with most attendees, but there were lots from Wisconsin and Illinois, and a smattering from Indiana, Minnesota, Michigan, Ohio, Nebraska, and Missouri. See the map below and the TPOS website for details.

A new feature of this conference was an App (courtesy of TNC) that would run on a tablet or smart phone that gave you the complete schedule, list of attendees, and all the abstracts. With good WiFi throughout the conference setting, this was very useful. (There was also a regular printed program.)

You should be able to see the abstracts and some of the recorded presentations in a few days on the TPOS web site. Here I am listing some of the sessions that I attended.

A major highlight was the Plenary paper by Bill Kleiman and Cody Considine of The Nature Conservancy summarizing 25 years of fire at Nachusa Grasslands. Nachusa is a very impressive large restoration, especially since almost all the work there, including burns, is done by volunteers. See the Nachusa website at this link.

I list here some of the sessions that I was able to attend:

  • Fire equipment (Rob Littiken)
    • What people are using and how it works
    • Real "nuts and bolts" stuff
  • Burn preparation and fireline placement (Erik Acker)
    • Very useful information on making fire breaks
  • Jumps, escapes, mishaps and close calls (Brad Woodson)
    • Lots of folks in the audience shared their stories
  • Using fire to restore oak sites--Case Studies
    • Missouri (John Murphy)
    • Iowa (Bryan Hellyer)
    • Wisconsin (Sara Kehrli)
  • Oak roundtable
    • Small group discussions of limits and needs for use of fire in oak systems
  • Fire histories and 60 years of change in Wisconsin savannas
    • Resurvey of Curtis' savanna sites (Laura Ladwig)
  • Fire and plant diversity of Wisconsin prairie remnants
    • Resurvey of Curtis' prairie sites (Amy Alstad)
In addition to the program, it was especially nice to see so many friends, not only from Wisconsin, but from other states. Kathie and I have been burning long enough now that we are getting to know a lot of folks in the "fire community".

Photos courtesy of the Conference website

Sunday, February 1, 2015

Fire as the key tool in sustainable management of Midwest U.S. savannas

Our goal at Pleasant Valley Conservancy is to ensure the long-term survival of one of the most endangered habitats on the earth, the oak savanna. Many of the bur oaks here are well over 200 years old, and the oldest bur oak measured here is 278 years old, which means it started life in 1736 (the rein of George II). Although our large white oaks are not as old, they probably started life in the mid 1850s. You can’t create an object like this, you have to find it and care for it. These are important trees, well worth spending money on.

Pleasant Valley Conservancy owns 104 bur oaks that are probably more than 200 years old!

Although these big oaks once had a fairly favorable time of it, since the 1950s when the savanna/prairie fires ended, they have had a serious struggle. Fortunately, we came along in 1995 and with the encouragement of Brian Pruka, Paul West, Pat Schrader, and many stalwarts from the Prairie Enthusiasts and the Wisconsin DNR, we have been able to bring this small piece of oak savanna back to life.
Distribution of large diameter bur and white oaks at Pleasant Valley Conservancy

Kathie doing the first burn at the
White Oak Savanna in early April 1999
We’ve been burning our savannas since they were first cleared in 1999. Our files are quite complete and according to our records, as soon as a savanna unit was cleared, we burned it (or attempted to burn it). These were annual burns, either spring or fall.

Originally, the savannas did not burn well, and lots of interior lighting was necessary. Why didn’t they burn well?
  • It took some years for the understory vegetation, which provides a lot of the fuel, to get established.
  • Although oak leaves, the other fuel source, were present, there was lots of downed timber, thus blocking movement of fire. 
However, we kept at it, doing lots of interior lighting, and annual seeding. With increased light the understory vegetation got better, the continued burns kept brush from getting started again, and gradually the burns got better.

Now, 15 years later, our savannas are in great shape. Even so, we cannot let up our guard.

In the savannas there is still a significant legacy of woody vegetation. What would happen if we stopped annual burns? Unfortunately, we know what would happen. Brambles, buckthorn, honeysuckle, sumac, prickly ash, and others would gradually return. We might be able to control it if we switched to a two- or three-year burn cycle, but all we would need would be to miss a year and have a four-year burn cycle and we would lose control. There are lots of publications in the literature on this.

Also, legacy effects are lots more significant with savannas than with prairies.

The term “sustainable” is fashionable right now. Mostly it is used with monetary value, but it seems to me it also has an important other meaning in conservation.

Our burn season starts on March 15 and continues to the end of April. Savanna burns are interesting to do, and you have the joy of knowing you are helping some important veteran oaks.

In addition, you are preparing the field for future generations of oaks!

Wednesday, January 28, 2015

Leaf blowers and prescribed burns

I've posted on leaf blowers before, but this deserves repeating.

One of the most useful pieces of equipment for prescribed burns is a heavy duty leaf blower. We have two and use them on every burn.

When we started doing prescribed burns about 20 years ago, the main tool to build a fire break was a hand rake. It’s hard for me to realize how primitive that was. To get a clean fire break it took a line of rakers, each following the one in front. This took a lot of time and three or four people. No wonder our burn units were so small!

After doing a primitive Internet search (no Google in those days!), I ran across a page where someone recommended using a leaf blower. For our third year of burns we rented a leaf blower, and never went back to a rake again. The following year we bought the largest leaf blower we could afford.

I’m not talking about those tiny leaf blowers that home owners use to clean their sidewalks. I mean a large, heavy duty leaf blower that pushes a lot of air. What is called a “Professional Blower”, the kind sold to landscaping professionals. The air velocity spec of the big Stihl leaf blowers ranges from 180 to 200 mph! Ours (Models 500 and 550) have what is called an Easy/Start feature.

Kathie says the blower should be powerful enough so that when you put it on full pressure you feel like you are getting ready to “take off” backwards! Some blowers have noise-reduction features but these are not necessary for use in rural areas. A good pair of ear muffs is fine.

Example of what a leaf blower can do on a fire break. This break is mowed several times during the growing season, and again just before the burn. Then a couple of passes with the leaf blower finishes the job. No danger of “creep” out of the burn unit! Photo from October 2014 oak woods burn.
Some people use a motorized lawn mower instead of a leaf blower. A riding lawn mower also works. These are fairly good as the first pass, but aren’t as efficient. Also, they don’t do a good job at the edges of the break. A riding mower was used for the first pass on the fire break shown here, followed up by two passes with the leaf blower (down and back).

Not only is a leaf blower essential for creating a good fire break, but it also has other uses on the fire line. It can be used for fire suppression in light fuels, and in mop-up operations, such as blowing smoldering material back into the black of a burn unit. We also use them to "fire-proof" around dead snags and other trees we want to protect.

Think fire, think spring!

Sunday, January 25, 2015

Oak savanna restoration: to seed or not to seed?

Oak savanna restoration is a long-term and expensive activity, but the results are worth it. Because it takes so long for a restored savanna to be established, careful long-range planning is essential.

Generally, one starts with a fairly degraded (former) savanna, containing numerous open-grown oaks, but heavily crowded with invasive trees such as elm, walnut, maple, box elder, or other fire-sensitive species. Also present are probably invasive shrubs such as buckthorn, honeysuckle, prickly ash, autumn olive, etc.

Let's take a 5-10 acre parcel. Here are the restoration steps:

  • Remove all the invasive trees, paying special attention to those that are crowding open-grown oaks. This step is sometimes called "daylighting the oaks."
  • At the same time, cut and treat all invasive shrubs, both native and non-native.
  • Burn the understory either in the spring or fall.
Some restorationists stop at this point, perhaps doing annual or biennial burns and waiting for the understory herbaceous vegetation to appear. Whether they realize it or not, those folks are assuming that there is a good "seed bank" still present and as soon as light is allowed in, those species will be "released". 

With highly degraded oak savannas, it seems unlikely that a complete complement of savanna species seeds will still be present in the soil. Some species may be present, but most will not be. Data from studies on prairies has shown that seeds of many prairie forbs and warm-season grasses, especially, do not persist very long. The main species that persist are hard-seeded types such as sedges and legumes. Since many of the savannas being restored have been degraded for over 50 years, it seems reasonable that the seed bank is greatly impoverished.

However, even if a seed bank may exist, why not plant? Experience has shown that it takes 5-10 years to get a good savanna understory established. Let's speed things up. Of course, the species planted should be those that already exist in the area (local genotypes). They will join with those arising from the seed bank, thus increasing the diversity. The only situation where seeding would not be warranted was if the site was part of a research study.

Excellent lists of savanna species are available from Brian Pruka, Steve Packard, and Brian Bader, and I have included them in my web site on oak savanna restoration.