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Grazing and Fire Management
Larry Allen 1
ABSTRACT
Natural and man-caused fires have been an important component
of grasslands and forests for many years. Fire suppression and
grazing in the twentieth century have changed the character of those
areas and the characteristics of fires that do burn. Fire is relatively
new to the lower desert regions, with the introduction of exotic grass
species. Many of the plants of these regions are not well-suited to
fire and characteristics of the low deserts have changed in some
areas.
A change in attitudes toward fires is needed. In many cases they
must be allowed to burn. This approach, however, must be
tempered by a full understanding of the characteristics and needs of
specific areas and the actual and perceived impacts on encroaching
population areas.
INTRODUCTION
We have heard today that a number of factors have influenced southwestern ecosystems.
Certainly cattle grazing is one of the bigger ones. There have also been a lot of other man-made
disturbances to the environment - mines, railroads, cities, farms, a lot of different things have
influenced these ecosystems. Probably one of the greatest influences has been fire, and in the last
century or so the exclusion of fire. It was said earlier, many of these fires were caused by lightning.
When I first started to work for the Forest Service, about 85 or 90 percent of our fires were lightning
caused. That's not the case any more. But, I think a long time ago we had man-caused fires too.
So, we had man-caused fires and then we had lightning-caused fires. But we had frequent fires in
southeastern Arizona.
We think that the Indians occasionally might have used fires for vegetation manipulations, but
probably more commonly for hunting and for war. We have the incidences that Kris showed us.
Another well known one is when the cavalry was at Bear Springs in the Whetstones and the
Apaches set that Bear Springs Canyon on fire. That's where lieutenant Cushing was killed, and as a
result he got a bar named after him.
FIRE SUPPRESSION
Now, the tree ring studies show some interesting phenomena on our mountain tops. And, as
we heard, they are now starting to look at lower elevations too. But, the thing that interests me is
the near cessation of fire in these ecosystems starting about 1900. Many people attribute that to
fire suppression and they blame the Forest Service. About 1907, when we assumed management
1
USDA Forest Service, Coronado National Forest, Tucson, AZ. Transcribed from conference tapes.
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of these lands, we had one or two rangers with a horse and a shovel in charge of a whole mountain
range who sent out here to put the fires out. Later on, about the time I came along we had more
modern equipment. But, obviously we werent very effective at it. Although we prevented the spread
of some fires, I don't think that caused the dramatic decline or decrease that the tree ring studies
show. Smokey Bear has had a big influence, but he didn't come along until about the 1950's. So, I
think that probably what we are seeing is a pattern caused more by livestock grazing. Livestock
have been in Arizona since about 1540, and they have been fairly prominent in Arizona since the
1700's. But, the big build up was about the time of the Civil War. That kind of coincides with the
tree ring data. After about 40 years of intensive livestock grazing, fires ceased.
There has been a lot written and studied about what are the factors that brought about the
changes in these ecosystems. I think that there are many varied factors, and that anyone who
espouses any one factor is guilty of an oversimplification. A combination of climate changes and
man-caused factors has resulted in, not total elimination, but certainly a marked decrease in the
effect of fire on these Sonoran grasslands since around the turn of the century.
MESQUITE SAVANNAS
We at one time had mesquite savannas. We think in many of our foothills type areas, this is
probably a fairly natural kind of a situation. If you have a combination of excessive grazing and
drought, you get a situation where it wouldn't matter what the humidity was, you can't burn this kind
of place without doing something to change the situation first. We improved livestock
management. I agree with Jerry, we have a lot of good research and I think we also have a lot of
good range management in the area. By the mid- 1950's or so, we had created enough fuels that
fires probably could have started to spread again. But, by then the agencies were becoming pretty
efficient at putting fires out. So, just about the time that the livestock ceased to be a problem, the
agencies became the problem.
FIRE IN THE SONORAN DESERT
In our Sonoran area we have several different ecosystems, and one that has not evolved with a
lot of fire is the Sonoran desert. This desert does not naturally support very much perennial grass.
So the years that it will burn very hotly are pretty rare. As a result the desert plants that we really
value in the Tucson area are pretty susceptible to fire, easily killed. This causes a problem to those
of us who advocate reintroduction of fire. Another problem with fire in the Sonoran desert is the
great abundance of exotic species such as Lehmann's love grass in Arizona and buffelgrass in
Sonora. These areas have a fuel base that they never had naturally, and these exotic species have
spread. We saw some examples of that this morning of damaging fires as a result of buffet grass.
This can happen in some of the Lehmann's areas too. And, as Jerry said, unfortunately we have not
been able to find a way to use fire as a tool to manage Lehmann's. It seems to thrive on fire.
Another challenge to us is the great public interest. When fires start to bum, whether they are
good or bad, the local publics get very mterested. Some people are concerned about what they
perceive as forest destruction, other people are concerned about their homes and the
improvements they have built close to the fire. The public scrutiny that we have nowadays
complicates the situation quite a bit.
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THE CHIHUAHUAN DESERT
In the Chihuahuan desert areas, we don't have the spectacular cacti, but we do have some
plants that are also susceptible to fire. There has been a lot of concern expressed in the literature
about black grama. They think that burning the stolons can significantly damage black grama. Our
experience in the Malpai area, at a little higher elevation, and a little higher rainfall, suggests that it
doesn't seem to be as bad a problem as it is down in the desert. Anyway, we need to be sensitive
to the fact that some of our grass species are more susceptible to fires than others. So, reviewing
these factors, then, if we for a variety of reasons, remove fire from the ecosystem, we no longer
have the natural pristine kind of an ecosystem. The result of having this bare soil, eventually is the
encroachment of woody plants and probably encroachment into areas that didn't support them or
didn't support them in any numbers in the pa£t, with deterioration of wildlife habitat and watershed
values as well as forage.
WOODLAND AND RIPARIAN AREAS
In our woodland areas, we think that where you have a mosaic of open grasslands, savannas,
and then some dense woodlands is probably a natural state, and certainly a very desirable situation
both for livestock and wildlife, and kind of pretty to look at too. The ecologic tendency in our
woodlands is towards these dense woodlands. If you remove fire from those ecosystems, you get
denser growth. Our riparian areas seem to be naturally fire resistant. The humidity is a little higher,
the plants that are there are not as flammable. Fire burns through these areas periodically, and
they seldom do much damage. In our prescribed burning efforts we try to prescribe cool fires in the
riparians and exclude fire from a few critical ones. But, most of the time fire is not a big problem in
the riparian area.
CONTROLLED BURNS
As we start to do management-ignited fires, we have to consider all of these factors together,
and it gets to be a complicated planning process. The last fire that I planned took about nine
months. The current one we are working on has taken almost two years to get through all the
hoops. I think that fire can and should be used to maintain and enhance biodiversity and it should
be recognized as a natural part of the ecosystem. It is a desirable part, unlike the Smokey Bear
syndrome that we have been living with. I am encouraged by recent policies coming out of
Washington, although I have seldom in my career been very encouraged by anything out of
Washington. The Department of Interior, and Agriculture and Army, have recently come out with a
unified fire policy, which has a lot of common sense, a lot of advocation of prescribed natural fire
and use of fire as a tool. I am very encouraged by that. I'm not particularly encouraged by the fact
that is has been out for 6 or 8 months, and the agencies are slow to respond. But, I think we are
on the right track. I would emphasize that folks in southern Arizona really value the Sonoran desert
vegetation, and we need to recognize that and be careful. These fires have the potential to set back
our burning program because of the possibility that cacti will be killed. But, I think all of the
agencies recognize the value of putting fire back into the ecosystem that evolved with fire. We also
recognize the fact that you can't do it overnight. I hear people advocate that if suppression is the
problem, then just say no, and quit suppressing fires. Particularly on our mountain tops, that
doesn't work without some fuel modification first. But, we need to be headed towards much less
suppression.
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We also need to be aware of the needs of our neighbors south of the border. I've been involved
in fire training and providing tools to our counterparts in Sonora. I am trying hard to avoid the
impression that what the Forest Service is saying to the Mexican Forest Service is you ought to put
the fires out. I will be involved this winter in meetings in small towns in Sonora and will talk to
people about fire management as opposed to fire suppression. I think working together, we have
an opportunity with the agencies working together with the folks who live and use the land, to really
bring about some improvement in these ecosystems. Through a little more sensible fire
management and the application of fire as a tool, and then we'll create habitat for all these
interesting animals that inhabit the border area.
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