From "Managing Michigan's Wildlife: A landowner's guide"
There are 4 basic burn techniques used in the prescribed burning of
grasslands. These four techniques include:
- back fire
- parallel (flank) fire
- perimeter (ring) fire
- strip head fire
Each method has strengths and weaknesses depending on the weather conditions,
size of the area, and expertise of the individuals conducting the fire. Special
considerations when conducting the burn include power lines, telephone lines,
and oil or gas lines.
A backfire is used downwind of the burn site. This is most often the
coolest and safest fire. However, it is slower burning and therefore takes
longer to finish. The fire is ignited on the downwind side of the fuel and
slowly burns into the field against the wind, expanding the firebreak. This burn
technique is often used in conjunction with other burn methods.
A strip head fire burns slightly faster than a backfire, is relatively
safe, and works well for burning rectangular or odd shaped parcels. It is also
cost-effective. A series of strips are lit, starting at the downwind side of the
site. Ideal when burning with a limited number of
personnel.
A parallel or flank fire burns hotter and faster than a strip fire or
backfire. It works well on square or circular parcels. A fire is ignited on the
sides of the burn site parallel to the wind direction at the same time or soon
after a backfire is lit. The people igniting the fires on either side should
keep continuously in touch by 2 way radio.
A perimeter fire is not only one of the quickest burn methods, but
also creates a hotter fire than those listed above. Since this type of burn
technique develops a hotter and faster moving fire, which can be harder to
control, it must be handled carefully. This method starts with a backfire,
followed by lighting the flanks, and finished by lighting the upwind side of the
burn site called the head of the site. This headfire will move rapidly towards
the flanks and backfire.
Remember that when choosing a burn technique, your level of experience
with burning and that of your burn crew should be a major factor in your
choice.