According to Dan Zay, there is no one-right-answer. If your goal is to economically control brush in fence rows with a secondary goal of increasing biological diversity, then burning once every five-to-ten years may be the right answer.
If your goal is to maximize biological diversity and you have a relatively large site, the best answer may be to have different burn regimes for different sections of the tract.
Native Americans used fire in several different ways:
...a typical southern woodland village. Located on a stream or river, the clearing for the village and surrounding fields of mostly corn, beans, and squash extended for 4 miles. Girdling larger trees and burning the undergrowth cleared this area originally, and burning kept it open, in much the way that swidden agriculture occurs in the tropics today. The field zone was buffered by a further 1.25-mile-wide zone that was burned annually for defense (visibility), where fuel wood and berry gathering took place. Another 1- to 2.5-mile-wide zone was burned frequently for small game and foraging. This entire disturbance complex was surrounded by closed forest. Nearby was a large zone kept in open grassland by burning for large game animals. Except in river floodplains, this village complex had to be moved periodically as soil fertility was reduced in the continuously cropped fields and as nearby fuel wood was exhausted. To maintain proximity to open grassland for hunting, successive village sites were probably within 6 to 25 miles of each other.
Pyne (1997) described the careful use of fire by Native Americans
- Cereal grasses were fired annually
- Grassy savanna hunting areas annually
- Basket grasses and nut trees every 3 years
- Brush and undergrowth in forests were burned for visibility (to diminish cover for adversaries who might attack the village) and game every 7 to 10 years.
Fire also was used to drive and surround game (Hudson 1982) and reduce the threat of wildfires, especially along the coast, where pines dominated and lightning provided an ignition source.
Even in areas of the Southern Appalachian Mountains that were sparsely settled and not prime hunting ground, major trails that followed rivers were kept open by burning, and escaped campfires probably caused large areas to burn. (Source...well worth the read)
Note that the prevailing trees in Appalachia are shifting from oak to Red Maple and Tulip Poplar due, most likely, to the withholding of fire.
(Another good read on Native American use of fire HERE)
After your local Fire Department gives you the OK. That "OK" will probably come with certain conditions like wind speed and direction and time of day to start-and-stop.
I leaned on one of my favorite fire fighters. I wanted to be able to give you a "cook book".
My friend declined to provide that information for the following reasons.
Look, Joe, the best way to do this is to contact the fire department with jurisdiction where you want to burn. It is great if you can provide them with a Google map with the areas you intend to burn highlighted.
But the Chief is probably going to want to drive out to the property and lay his eyeballs on it because every burn is situational. He wants to assess the fuel load and the slope....things that don't show up on maps. The best time to do this, if you plan a spring burn, is right after the snow melts. Then he can see how high the grass is and assess any containment risks downwind of the planned burn site.
Another thing is that most of the fire fighters assist with ambulance runs. They know which residents suffer from asthma or have COPD. They may specify that the burn only be done when the wind will carry smoke away from that one, high-risk resident.
The final consideration is that enlisting their help makes them your partner. Heck, they might want to use your burn as a training exercise.
A few more bonus links suggested by Dan Zay:
What is a Savanna?What is a savanna? By Geroud Wilhelm
The Importance of Ecological Restoration. By Geroud Wilhelm
Conservation Design Forum Much information for upper mid-West (Centered around Chicago)
Timberhill Savanna Assessment of Landscape Management - See more at: http://www.cdfinc.com/Publications#sthash.IyHjQPmu.dpuf
Gerould S. Wilhelm
What is a Savanna?