Controlled (Prescribed) Burns

March 2019 burns

After a cold early March, the weather improved and over 4 days we were able to get lots of our big burns done. Over 80 acres, as shown on the map. Only the North Woods and Wetland remaining to be burned.

March 2019 burns



See this link for a history of burns at Pleasant Valley Conservancy

See Tom's Blog for narratives of burns of recent years


Why do we burn?

One of the most important management tools in restoration ecology is fire.

Fire is a natural element in the ecosystem, and under appropriate conditions may develop spontaneously as a result of lightning strikes. Lightning-caused fires occur mainly during warm windy dry conditions and hence occur rather randomly. However, tree ring studies have shown that most oak savannas were burned frequently, generally every few years.

Imitating nature, humans throughout the world have used fire for thousands of years. In North America, fire was used by Native Americans to encourage berry production, expose acorns for collection, prepare planting sites, control undesirable pests, fireproof villages, create and maintain open woodlands and savannas, concentrate game, and help maintain trails. Fires were ignited in the dormant season, either in spring, before plants had started to grow, or in fall, after frosts had killed above ground parts of plants.

When European settlers displaced Native Americans, the use of fire continued, for many of the same reasons. In the hill country of southwestern Wisconsin, farmers continued to use fire to keep grazing land from getting choked with brush and weeds. Early spring burns encourage the growth of grasses by removing detritus and debris, and by top-killing shrubs.

However, the 20th century introduced the era of "fire suppression", which as we now know was misguided. It was eventually understood that fire suppression was having unintended consequences, destroying the values that prairies and oak forests provided, and replacing native habitat with undesirable trees and shrubs. It was not until the 1980s that fire was seriously reintroduced as a management tool for oak savannas and woodlands, introducing what the U.S. Forest Service calls the "fire management era". "The Fire Management era is generally characterized by a major shift from fire suppression to a period of increasing knowledge and understanding of fire ecology and the response of varied ecosystems to altered fire regimes."


A typical prairie/savanna burn on the south-facing slope at Pleasant Valley Conservancy. The two photos were taken at the same location (note the small double tree in the middle). The burn was done on March 19. The photo on the left was taken on September 13.


Prescribed Fire

The term "prescribed fire" refers to fires that are set on purpose according to a written and approved plan, the prescription. The plan describes the objectives of the burn and the expected results. The burn plan specifies, either in words or by a map, the parcel of land to be burned, the landowner(s), and owners of adjacent land not included in the burn. Any considerations of smoke management are identified. The burn plan specifies the required governmental permits, and lists those who must be notified on the day the burn is to take place. The locations and characteristics of all fire breaks are given, as well as strategies for containment of fire within the burn unit. Any preparations of the burn unit needed before the burn can take place are indicated, including a list of fire sensitive elements within or near the burn unit that must be protected. The burn plan should state the personnel needed, as well as their qualifications and duties. The burn plan also lists the equipment needed to conduct the burn.

In Wisconsin, prescribed fire is now a critical management tool for organizations such as The Nature Conservancy, The Prairie Enthusiasts, Pheasants Forever, and the Wisconsin Department of Natural Resources. Many private landowners also use prescribed fire on a regular basis. The U.S. Department of Agriculture, through its Natural Resources and Conservation Service, strongly promotes the use of prescribed fire in management of private lands that have been dedicated to various soil and water conservation programs. The Wisconsin Prescribed Fire Council strives to make the use of fire in Wisconsin safer and more accepted. A number of commercial contractors carry out prescribed burns for landowners.

Even the forest industry now realizes that fire plays a major role in the oak forest, removing many weedy trees and shrubs. Prescribed fire removes the thin-barked shrubs and trees from the midstory and understory of the forest without harming the dominant oaks. Fire also consumes the litter, thus promoting the growth of grasses and forbs, and encouraging the regeneration of oak. Long-term research studies have shown that annual burns over a number of years gradually restore the oak savanna to its original state.


Prescribed burn in a bur oak savanna. Note how the fire hugs the ground. The principal fuel is oak leaves.

History of Fire Use at Pleasant Valley Conservancy

Pre-restoration burn history
According to oral reports, the farmers who had settled the Pleasant Valley Conservany area (the Lockwoods) had used fire every year to encourage early "green up" of the grazing land. The south-facing slope as well as the white oak savannas surrounding the Pocket Prairie were burned. There is photographic evidence that the south-facing slope was treeless, which would only occur with frequent fire.

After landowner Harold Lockwood died in the 1950s, the land fell into absentee ownership and fire was no longer carried out.

Early restoration burns
Fire was introduced to Pleasant Valley Conservancy soon after restoration work began in 1997. The first burn was a small one (about 0.5 acre) carried out on the Unit 1 remnant. This was successful and the prairie responded dramatically.

In 1998 the first major burn was done by The Prairie Enthusiasts. The two prairie remnants burned well but most of the south slope burned poorly or not at all. The following day Kathie returned to the south slope with a drip torch and carefully relighted the whole thing. The photo shows her in action.

The results were dramatic. The south-facing slope that had originally been heavily brushed in was opened up, prairie grasses began to flourish, and many prairie forbs appeared.

Kathie stripping the south-facing slope on 8 April 1998. The Prairie Enthusiasts had unsuccessfully tried to burn this slope the day before. After Kathie's work, the slope responded dramatically with lots of prairie grasses and forbs.


Thus, beginning with two small prairie remnants of about 0.5 acre each (Units 1 and 4), the whole south slope eventually was restored and burned. In recent years, south slope burns of 20-25 acres are being carried out.

See this link for a summary of the 20-year burn history at Pleasant Valley Conservancy.

Present burn policy
Most of the upland areas are burned annually, generally in the spring although occasionally in the fall. Prescribed burns are our most important management tool, and are closely integrated into our invasive plant control program. Without prescribed burns, the control of invasive plants would be much more difficult, in many places almost impossible.

The way we do them, burns do not harm wildlife. Midwestern wildlife evolved in a fire-prone environment and has adapted to fire. The larger animals are able to move away from fire. We burn in the dormant season of either early spring or late fall. No burn is 100% complete and smaller animals survive in the numerous refugia that remain unburned.

Burn refuges

Unburned areas always occur during prairie burns, and provide refugia for small animals. The photo here shows a typical example in the Crane Prairie. Refuges are even more common in savanna and woodland burns. Likewise, major unburned areas occur in wetland burns.


Prescribed burn of the south-facing slope carried out in March 2003, after 5 years of restoration work. The principal fuel is little bluestem and Indian grass.


Starting in 1998, annual savanna burns have also been carried out. These burns have proceeded in tandem with control of brush and weedy trees. These burns of 50 or more acres of oak savanna or oak woodland are responsible for the high quality of the Pleasant Valley Conservancy oak habitats.

Burns have also been carried out in the north-facing oak woodlands. The first burn was done in the fall of 1999 and was very successful. The north woods was burned again in spring 2007, fall 2008, spring 2009, fall 2010, fall 2012, fall 2014, and biennially since. Fall burns are the best for the north woods because of its aspect (N-facing). Occasionally the north slope is burned in the spring.

The table shows which units have been burned over the past 20 years.


Lady slipper orchid (Cypripedium caleolus) growing out of the ashes of the fall burn of the north woods. A large number of these orchids developed in the spring after the burn, noticeably more than usually develop.


Each year using GIS we prepare a map of areas that were burned. The ones for the 2007-2008 and 2008-2009 burn seasons are shown below.

Burns done in Fall 2008 and Spring 2009. Dates shown on the labels.



The Burn Permitting System

Burn permits are required in our part of Wisconsin between January 1 and May 31. The rest of the year we can burn without a permit, although we must notify the local fire department (Black Earth Joint Fire District) that we will be burning. Therefore, we can carry out fall burns without a permit, but need one for spring burns. Our permits are issued by the Fire Control Ranger of the Division of Forestry of the Wisconsin Department of Natural Resources. Most of our burns are carried out between the middle of March and the end of April. (These permits are for daytime burns. Burns carried out after 6 PM can be done with a permit issued by the local fire warden.)

Every February we submit to the Ranger our spring burn plan. Based on this plan, our permits are issued, one for each burn in our plan. However, we must obtain oral authorization from the Ranger on the day of the burn. We reach the Ranger through the District Office in Dodgeville. Once we have authorization, we can proceed with the burn.

Note that although the prescribed burn program is administered through the Division of Forestry, it does not include only forests. Prairie and wetland burns are also regulated by the Forest Ranger.


Burn Equipment Used at Pleasant Valley Conservancy

We are well equipped to carry out safe and effective prescribed burns.

Water Our electrically operated well provides an unlimited amount of water.

Pumper Units Kawasaki Mule (4 WD All Terrain Vehicle) with 65 gallon tank, 100 feet of hose, high-pressure hose nozzle, 5.5 HP Honda gasoline operated engine. An additional 200-feet of hose can be added if needed.

Backpack Water Sprayers We have six backpack water sprayers with special waist-band harnesses. These 5-gallon unist have brass slide-action hand-operated pumps. It is possible to spray precisely and accurately. This sort of unit is useful for putting out small (spot) fires or for controlling fires in areas inaccessible to ATVs or trucks.

Flappers We have two flappers for use in putting out small spot fires.

Drip torches We have three drip torches capable of dispensing fire (lighted fuel) along a fire line or throughout a burn unit. The tank is a heavy-duty aluminum canister with a specially designed fire nozzle equipped with a safety loop that prevents flashback. A check valve in the cover provides a second level of protection against flashback. The fuel is a mixture of 2 parts diesel and 1 part gasoline. Once lighted, the fire drips slowly out of the end.

Two-way radios We have ten wide range two-way radios, each capable of reaching anywhere in the Conservancy. Our radios are Kenwoods that are capable of transmitting up to 6 miles, even over rough terrain and through smoke. Special hands-free harnesses are used.

Fire protective clothing We wear Nomex fire protective clothing.

Additional equipment from the Prairie Enthusiasts We can also borrow additional equipment from the Empire-Sauk Chapter of the Prairie Enthusiasts including more two-way radios operating on the same frequencies, more drip torches, more backpack water cans, and more flappers.

Mule pumper unit
Use of the drip torch
Worker equipped with fire-resistant jump suit of Nomex. The water can is mounted on a used knapsack frame.


Custom-made signs are used at the road corners to inform people of what is going on. If there is any danger of smoke blocking the road, personnel are assigned to control traffic.  



Summary of Burns Carried out at Pleasant Valley Conservancy

Most of the 140 acres of Pleasant Valley Conservancy has been burned at one time or another, and many areas are burned annually. The table below provides a brief summary.

CRP: Conservation Reserve Program; CREP: Conservation Reserve Enhancement Program

Area Units Type of habitat Character Frequency of burns Notes
Barn Prairie 0.8 acres Planted 2001 Wet mesic Annual ( spring or fall) Formerly cropped
Crane Prairie 3 acres Planted 2005 Wet mesic Annual (usually spring) Wooded marsh edge restored
North-facing slope Units 15, 16, 17 Woodland Mesic Biennially (seven times since restoration began in 1998) Last burned fall 2014
Pocket Prairie 4.5 acres Planted 1999 Dry mesic to wet mesic Annual (usually spring) CRP
Ridge Prairie 2 acres Planted 2005 Dry mesic Annual (usually spring) CRP
East Basin 5 acres Planted 2009 Dry-mesic to wet-mesic prairie; partly open savanna Annual (usually spring) Major tree removal in 2008
Savanna Units 8, 10, 11, 12, 18, 19, 21 Restored savannas Dry mesic to mesic Annually (fall or spring) Bur oak and white oak savanna
South-facing slope 1, 2, 3, 4, 5, 6, 7, 9, 23 Prairie and savanna remnant Dry mesic Annual (spring) Short to tallgrass prairie grading into bur oak savanna
Toby's Prairie 3.5 acres Planted 1998 Dry mesic Annual (spring) CRP
Valley Prairie 4 acres Planted 2002 Dry mesic to wet mesic Annual (usually spring) CREP
Wetland 40 acres Marsh, sedge meadow, shrub carr, stream bank Wet (standing water) or wet mesic Whole wetland in 2005, 2010, 2013; small parts occasionally Major effort; expensive
Woods thru service road area Units 20, 21 Prairie, savanna, and woodland Dry-mesic to mesic Annually (usually spring) Restored 2002; part faces steep ravine
North-facing oak woods Units 15, 16, 17 Oak woods Cool, mesic Biennially in fall on even years Red oak forest; spring ephemerals


20 year burn history

The table below provides a unit-by-unit summary of burns between the years 1997 (when the first burn was held) and 2017. Spring and fall burns are separated and vegetation types are shown. The numbers in some of the cells are the designations of individual management units. North woods (Units 15 and 16) has been burned biennially from 2006 thru 2016 and parts again in the spring of 2017.

See this link for locations of specific management units.

Year Season South slope Ridge-top savannas White-oak savannas
Unit 13 + Triangle Units 20 + 21 North woods
1997 Spring 1 only                      
1998 Spring 7-Jan 12B   Toby N 1/2                
1999 Spring 1-4, 6-7 11, 12B     Pocket (August) Valley (Brome)            
1999 Fall                       15 +16
2000 Spring 1-6, 23 8, 10, 11 12B Toby N+S                
2000 Fall   11                    
2001 Spring 2-7, 9, 23 8, 10   Toby N+S                
2001 Fall   19                    
2002 Spring 1-7, 9     Toby N+S   Valley (after glypho) Barn          
2002 Fall   8, 10, 19 12AB             Tri    
2003 Spring 1-7, 9, 23     Toby N+S Pocket   Barn         17 (part) with Toby
2003 Fall   8, 10, 11, 19 12AB +18                  
2004 Spring 1-7, 9, 23     Toby N+S Pocket   Barn     13 + Tri 20 + 21 17 (part) with Toby
2004 Fall   8, 10, 11 12AB+18       Barn          
2005 Spring 1-7, 9, 23     Toby N Pocket Valley       13 20 + 21 17 (part) with Toby
2005 Fall             Barn     Tri    
2006 Spring 6-7, 23 8, 10, 11A-C, 19B 12AB Toby S Pocket (W 2/3)         13 + Tri    
2006 Fall   8, 10, 11 12B+18     Valley Barn          
2007 Spring 1-7, 9, 23 11D, 19C-E 12A+18 Toby N+S Pocket         13 + Tri 20 + 21 15+16
2007 Fall                 Crane      
2008 Spring 1-7, 9, 23 8, 10, 11, 19B-E 12AB+18 Toby N+S Pocket Valley       Tri 20 + 21  
2008 Fall       Toby N+S Pocket Valley (partial)       Tri   15+16+19A
2009 Spring 1-7, 9, 23 8, 10, 11, 19B-E 12AB+18 Toby reburned reburned Pocket Valley   Ridge Crane Tri 20 + 21 rebrned+17 (part)
2009 Fall                        
2010 Spring 1-7, 9, 23 8, 10, 11, 19A-E 12AB+18 Toby N+S Pocket Valley Barn Ridge Crane 13 + Tri 20 + 21  
2010 Fall   19A                   15+16+19A
2011 Spring 1-7, 9, 23 8, 10, 11, 19A-E 12AB+18 Toby N+S Pocket Valley Barn Ridge + East Basin Crane 13 + Tri 20 + 21  
2011 Fall             Barn   Crane      
2012 Spring 1-7, 9, 23 8, 10, 11, 19A-E 12AB+18 Toby N+S Pocket Valley + Nearby Wetland Barn Ridge + East Basin Crane 13 + Tri 20 + 21  
2012 Fall   19A             Crane     15+16
2013 Spring 1-7, 9, 23 8, 10, 11, 19A-E 12AB+18 Toby N+S Pocket Valley + Nearby Wetland Barn Ridge + East Basin Crane 13 + Tri    
2014 Spring 1-7, 9, 23 8, 10, 11, 19A-E 12AB+18 Toby N+S Pocket Valley + Marsh strip Barn Ridge + East Basin Crane 13 + Tri 20 + 21  
2014 Fall                       14 +15+16 + Quarry
2015 Spring 1-7, 9, 23 8, 10, 11, 19A-E 12AB+18 Toby N+S Pocket Valley + Nearby Wetland Barn Ridge + East Basin Crane 13 + Tri 20 + 21  
2016 Spring 1-7, 9, 23 8, 10, 11, 19A-E 12AB+18 Toby N+S Pocket Valley + Nearby Wetland Barn Ridge + East Basin Crane 13 + Tri 20 + 21  
2016 Fall                       14 + 15+16 + 17 +Quarry
2017 Spring 1-7, 9, 23 8, 10, 11, 19A-E 12AB+18 Toby N+S Pocket Valley + Nearby Wetland Barn Ridge + East Basin Crane 13 + Tri 20 + 21  
2017 Fall                       16 +17
2018 Spring 1-7, 9, 23 8, 10, 11, 19B-E 12AB+18 Toby N+S Pocket Valley + Nearby Wetland Barn Ridge + East Basin Crane 13 + Tri 20 + 21  
Burn photographs