Prescribed Burning
By James Haywood and Finis Harris,
USDA Forest Service, Southern
Research Station and Kisatchie
National Forest, respectively.  Contact
address:  James Haywood, 2500
Shreveport Highway, Pineville, LA
71360; or e-mail: dhaywood@fs.fed.us


  1.	This presentation on prescribed burning by James Haywood and
Finis Harris with media assistance from Michael Elliott-Smith, Charlene
Howell, and Dan Leduc is a cooperative effort of the USDA Forest
Service, Southern Research Station and Kisatchie National Forest;
Louisiana State University Agricultural Center; and the Joint Fire
Science Program.

PLEASE NOTE:  This text file accompanies the 'slides' in the companion
presentation.  This is intended to be a 30- to 45-minute presentation.  You
may use all are only a portion of the slides, as you see fit.  However, please
give credit to the USDA Forest Service, Southern Research Station and
Kisatchie National Forest; Louisiana State University Agricultural
Center; and the Joint Fire Science Program as the source of these
materials and for funding this project.  The first slide shows the logos
for the supporting institutions and should be included in the talk.

  2.	Open range.  A discussion of prescribed burning should start at the
beginning when 10's of millions of acres of the South resembled this open
range--over-cut, over-grazed, over-burned, and often eroded.  The
reaction to the destruction of the vast southern pine forests was to
reestablish trees by planting, direct seeding, or reliance on natural
regeneration where available.  The key was to stop indiscriminate burning,
bring the range under livestock management, remove free-ranging hogs,
and protect young forested stands from fire.  This cooperative effort took
many decades and involved federal, state and local governments, industrial
forest companies, and innumerable private landowners.  It is one of the
great success stories of our nation.

  3.	Longleaf pine shelterwood.  Today's forests are a testament to this
effort.  Prescribed burns can be easily applied within open landscapes of
pine such as this shelterwood that is being reserved for wildlife habitat.

  4.	Prescribed fires scorch many of the pine seedlings growing in
openings in the shelterwood stand.  However, most of them will recover.

  5.	Natural drainages are not plowed out because when conditions are
right for prescribed burning the fire goes out once it leaves the drier pine
upland and enters the wetter bottom.

  6.	This slide shows the fire fingering out once it enters the wet bottom.

  7.	The Forest Service burns large landscapes for wildlife management
purposes.  On this shelterwood, the primary species of interest is the red
cockaded woodpecker, but across the South nearly 200 plants and animals
must have this type of open forest cover to survive.   Prescribed fire is the
best tool for managing habitat needed by these plants and animals.

However, should private landowners burn?  Before answering that
question, let's discuss the pitfalls of burning.

  8.	Too Much Fire.  Any discussion about prescribed burning should
cover the problems people encounter when burning, and too much fire is a
serious problem.  Nitrogen is always volatized in fires, but nitrogen fixing
microorganisms and plants replenish this nutrient.  However, phosphorus
and potassium in the ash are also transported from the site in the smoke
plume.  Intense fires that destroy most of the surface organic matter can
result in more phosphorus and potassium being lost than is returned to
the site from the atmosphere or by natural weathering processes in the soil.

It may seem that avoiding "too much fire" would be simple enough by using
monitoring procedures that track the wetness of fine fuels (pine litter or
dead grasses).  For example, the Keetch-Byram Drought Index is used for
this purpose, and it would seem that fires would not get out of control.
Unfortunately severe fires still happen, and often times we don't know why.

  9.	Too much large-diameter fuel.  Large-diameter fuels, often not
considered when burning forests in the South, may be more of a factor than
once thought.  This graph of Palmer's Drought Severity Index (PDSI) tracks
the 1998 through 2000 drought in southeastern Mississippi.  The drought
steadily worsens until November 2000, when it ends.

10.	The relationship of PDSI to large-diameter fuel moisture.  The
next figure again shows the PDSI (P) values for west-central Mississippi
but with the relative moisture content values of two logs laying on the soil
surface superimposed (1/Kpa).  The small log (S) was 4.5-inches in
diameter and the large log (L) was 11.5-inches in diameter.   As the
drought worsens, the PDSI and moisture content values follow each other.
However once the drought ends, the moisture content value of neither log
recovers although the drought ended many months earlier.

This implies that on some sites where large-diameter fuels are a significant
component of the total fuel load, these large fuels could create fire
intensities greater than predicted if you are only tracking fine fuel moisture
conditions.  Site preparation areas and stands where trees have been
injected or otherwise killed by chemical or mechanical means are situations
where large-diameter fuel conditions would support fire intensities greater
than those predicted by standard monitoring techniques.  These facts are
self-evident in the Interior West where yearly droughts occur over whole
regions producing millions of acres of overly dry large fuels.  We just have
not paid enough attention to this problem in the South--that is until recently.

11.	Scorch.  Scorch can occur over large areas when prescribed burns
are poorly conducted.  This stand contained hundreds of acres of scorched
40-year-old slash pine.  The trees recovered but volume growth was lost as
the trees rebuilt their crowns.

12.	Dead tops.  Recovery does not always happen.  Even large pine
trees can be killed in prescribed fires or their crowns severely reduced.

13.	Too much fine fuel.  Even when only fine fuels are burned, intense
fires can result because high fuel loads are present (3,300 to 6,000 lbs/acre
of dry fuels) in some young pine stands.

14.	Fire sequence: The headfire rapidly increases in intensity.
15.	Fire sequence: Waxmyrtle, a highly flammable shrub, ignites.
16.	Fire sequence: The fire is at maximum intensity.
17.	Fire sequence: Fuels begin to be exhausted.
18.	Fire sequence: The fire is nearly out.


19.	Severe scorch.   Nearly 100 percent scorch resulted from this burn.
At first glance, this stand appears to be a total loss.

20.	Buds protected.  However, if you pull back the dead needles you
see the terminal buds were protected.

21.	Check trees.  Still if you look at the un-scorched trees on the
unburned areas, it is not hard to realize that growth was lost because of an
intense prescribed burn in too much fine fuel.

22.	Too little fire.  Conversely, you can have too little fire to get the job
done, as on this site.

23.	This low intensity fire does not get the job done because there is not
enough fine fuel (pine litter or dead grasses) at the soil surface to keep a
fire going.  To work, the fuel must form a continuous bed--hence the term
fuel bed.  Here, most of the fuels are vertical and will not carry a fire across
the site.  As a result, the fire is spotty and the hardwoods are not controlled.

24.	Fire has to be periodically reapplied.  This Waxmyrtle height graph
shows the effects of periodic burning.  The blue line is for the unburned
shrubs.  The red line is for shrubs that are annually burned.  The yellow line
is for shrubs that are biennially burned, and the green line is for shrubs that
are triennially burned.  Between biennial and triennial burns, we can see
how much the shrubs recover, only to be reduced in height again.  Clearly,
burning must be reapplied to be effective.

Also, the last triennial burn, for some reason, was not as successful as the
earlier ones, and the shrubs are not nearly as well controlled as in the
previous burns.

25.	One poor burn can create problems.  A fire of too low an intensity
can result for a number of reasons.  For example, showers can create wetter
conditions than expected or put fires out, and fuel conditions may be less
conducive to burning as in the past.  For whatever reason, a poor burn may
result in the brush developing beyond a level that can be controlled with
prescribed burning in the future, at least at fire intensities most landowners
are willing to tolerate.

26.	Legal Issues.  Smoke management--The need to keep smoke off
nearby highways can limit the number of days available for burning.  Can
your neighbors tolerate smoke?  Fires can escape--are you ready to tackle
an escaped fire?  Air quality standards may become more restrictive in the
future limiting the ability to prescribe burn near large urban centers.

27.	So why would you burn?  There are good reasons to burn your
forest property. Forest access and aesthetics, fuel reduction especially
near homes and buildings, and wildlife habitat management are good
reasons to burn.  The closed natural forest pictured here is what nature
gives you without management.  This is poor habitat for animals needing
browse and herbaceous plants for food.  Many animals live in closed
forests, but there are millions of such acres, and you don't need to provide
more.

28.	No forage.  The floor in this closed natural forest provides little or no
food for wildlife.  It is an unproductive site with little recreational value.  It
would be better to burn this forest to provide productive, open habitat for
wildlife and keep dense closed areas used mostly for cover to a minimum.
IN FACT, prescribed burns rarely burn everything, and natural drainages
(remember our earlier examples) and upland "islands" of unburned
vegetation usually provide all the cover needed.

29.	Fire reduces understory brush.  Fire can keep understories open
and producing browse for wildlife.  Here we see brush killed back to the
ground by fire.

30.	Following the fire, the brush begins to recover and provides fresh
nutrient-rich browse for wildlife.

31.	Fire stimulates herbaceous plant growth.  Fire stimulates
legumes, which are good for wildlife.   Most of the plants shown in this slide
are partridgeberry, a good food source for wildlife.  Grasses also flourish
after burning.

32.	The trick is to reapply fire.  This vegetation will need to be burned in
the next year or two to keep its wildlife value at a maximum.  One burn is
not going to do the job.

33.	Burning House.  Heavy fuel conditions may be dangerous near
homes and buildings.  Fire can be used to reduce fuel loads in the
urban/forest interface.

34.	Pine straw harvesting.  Alternative management schemes can also
reduce brush without the need to burn.   For example, pine straw
harvesting can control understory vegetation and remove the fuel bed
necessary for a wildfire to spread across your property.

35.	Goats.  Livestock can be used to keep brush and herbaceous
vegetation under control.  However, unless you are predisposed to begin a
pine straw or livestock enterprise, these two options are not likely solutions
to your fuel problems.

36.	Mechanical equipment.  The device mounted on this tractor is a
rotary mulching head used to grind up midstory-size trees and shrubs.
Such devices are normally mounted on a wide-wheel skidder to lessen
compaction on forest sites and sometimes used to control midstory
vegetation along highways and in red cockaded woodpecker colonies.
Understory brush could also be kept in check with tractor mounted rotary
mowers.  However, the number of acres you can treat with this kind of
equipment is limited.

37.	Herbicides.  To treat large areas, some type of herbicide treatment
may be necessary, whether applied by ground or aerial equipment.

Any of these alternative methods can be used in conjunction with
prescribed burning.  A fuel reduction burn may first be needed.  The woody
vegetation would then be chemically or mechanically controlled.  The dead
vegetation would be allowed to break down and fine fuels given time to
accumulate.  The next burn would follow in the next year or two depending
on the condition of the fuel bed.

38.	Conclusions.  Why burn: fuel reduction, wildlife management,
access, and aesthetics.  Why not burn: loss in stand growth and mortality,
legal issues, poor results are expected or have occurred in the past
necessitating another approach or a combination of treatments.

PLEASE NOTE: This presentation was prepared on official government
time, and is not copyrightable.  It may be used free of charge.

Contact address:
James Haywood
2500 Shreveport Highway
Pineville, LA 71360-5500

e-mail: dhaywood@fs.fed.us