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Aldo Leopold and the Evolution of
Ecosystem Management
Susan Flader1
I
Abstract - In his 1992 policy statement on ecosystem management, the
chief of th~ Forest Service stated a principle to "strive for balance, equity,
and harmony with land ... by sustaining what Aldo Leopold called the land
community." Aldo Leopold (1887-1948) developed his ecological approach
to land management and his concepts of land health and a land ethic
through a lifetime of observation, experience, and reflection? His most
penetrating observations came as a forest officer in the Southwest in the
early 1920s, when he sought to understand the problem of soil erosion and
the role of fire on forest watersheds. His forest inspection reports and other
writings of the time reveal a strong commitment to ecological analysis and
ecosystem-based objectives aimed at restoring the integrity of the
landscape. But his experience within the Forest Service as he sought to
develop objectives of management and principles of administration that
would move the service beyond its traditional bounds suggests that
implementing an ecosystem approach to management on national forest
lands may not be easy.
forests into the next centwy. Clearly, Aldo Leopold (1887-1948)
was a man ahead of his time. Just how far ahead is apparent
when we reflect that he made some of the greatest advances in
thinking about system-based land management during the first
fifteen years of his forty-year career, especially during the early
1920s.
This paper will examine Leopold's experience as a young
forester seeking to understand the dynamics of a landscape
subject to everchanging physical, biological, and cultural forces
and, in his definition of the problem and his proposed course
of action, pushing the still youthful Forest Service farther and
faster than it was prepared to go. We will seek to understand
something of what may be itwolved in implementing an
ecosystem approach to management within an agency culture
that is, if anything, more entrenched now in its traditional ways
than it was during Leopold's time. But we may also come to
appreciate through this stOly that the Forest SeIVice long has
had among its traditions a refreshing openness to mavericks like
Aldo Leopold.
Aldo Leopold graduated from the Yale Forest School in the
class of 1909 and left that summer for his frrst assignment in
the Forest Service, as forest assistant on the Apache National
Forest in Arizona Territoty (Flader, 1974; Meine, 1988). The
Apache was one of a series of newly created forests straddling
the highlands along the Mogollon Rim that trended from the
In his 1992 directive on ecosystem management, setting forth
a new management philosophy to guide the national forest
system as it enters its second century, chief F. Dale Robertson
declared a principle to "strive for balance, equity, and harmony
between people and land ... by sustaining what Aldo Leopold
(1949) called the land community." In this significant document
Aldo Leopold is the only person besides Gifford Pinchot to be
named and his 1949 classic, A Sand County Almanac, is the
only publication referenced. Consider the role Leopold occupies
in the progression of ideas that have guided the Forest Service,
as defined by Chief Robertson: Gifford Pinchot is credited with
articulating the conservation philosophy that underpinned
national forest management from the inception of the Forest
Service in 1905, the conseIVation approach was augmented by
the multiple-use philosophy enshrined in law in 1960, and now
Aldo Leopold's enlarged concept of the land community,
expressed most clearly in his essay on "The Land Ethic" in his
1949 book, has been identified by the chief as the basis of the
ecosystem management philosophy that will take the national
1 Susan Flader is Professor of American Western and
Environmental History, University of Missouri-Columbia.
2 This paper is based in large part on original, unpublished
manuscript material from Forest Service records and Leopold's
personal papers, most of which may be found in the Aldo Leopold
Papers, University of Wisconsin Archives, Madison, Wisconsin.
15
just then beginning to incorporate early concepts of ecology such
as forest succession and climax, it is perhaps natural to assume
that scientifIc management meant management according to
principles of botanical or even ecological science. Yet a careful
reading of early Forest Service administrative correspondence
makes it clear that the term "scientifIc management" referred
to the principles of industrial management just then being
articulated by the time-and-motion-study expert Frederick
Winslow Taylor (1911). Leopold himself was attracted to
Taylor's ideas by the early 1920s, when he became chief of
operations for all national forests in the Southwest, and he
participated avidl~ with his operation counterparts in other
regions of the country in a round-robin discussion of the
application of Taylor's ideas to forest administration.
This is not to say that there was no biological basis for early
forest management. There was, but the biological basis-which
was in part ecological-was simply assumed (Flader, 1976). As
such, it was scarcely open to question The ecological concept
of forest succession, the admonition to halvest only individually
matked, mature trees, usually of climax species, the absolute
control of fIre (which set back forest succession)-all these
notions were part of the ideology of Americanforestry-dogmas
assumed as givens, with little need of further testing or research.
Another given was the doctrine of forest influences, the belief
that forest tree cover at the headwaters of streams was crucial
in preventing destructive flooding and erosion downstream.
These doctrines, and more, would become open to question as
Leopold began to think hard about what he saw happening on
the ground in his new role as chief of operations and principal
inspector for twenty million acres of national forests in the
Southwest.
For fIve years, 1919-1924, Leopold criss-crossed the forests
of the Southwest, usually on horseback, observing conditions
nowhere more trenchantly than on "that tumbled sea of pale
blue hills" along the Mogollon Rim, where he had fIrst
encountered the Southwest as a timber "reconnaisseur" a decade
earlier. The reports of his earliest inspections were sketchy,
though he made it clear that he was still looking for imagination
and initiative on the part of forest rangers and was determined
to judge their success by the effects of management on the forest.
In particular, he began noting the effects of gullying and soil
erosion on forest ranges and arguing for actual work on the
ground to test and improve techniques of management. By early
1920, during an inspection of the Prescott National Forest, he
wrote home to his mother that he was "seriously thinking of
specializing in erosion control. The problem is perfectly
tremendous here in the Southwest and I seem to be the only
one who has any faith in the possibilities of tackling it
successfully. "
Despite his inclination to deal with real problems on the
ground, Leopold in his new operations post again had to
overcome doubts about his administrative ability on the part of
both subordinates and superiors, who thought of him as
highbrow and inattentive to detail, moving along "with his feet
somewhat off the ground." As he had several times previously,
Prescott Forest near Flagstaff three hundred miles southeastward
to the Gila in New Mexico Territory. It was the region where
Leopold would make the most telling obselVations of his
fIfteen-year career in the Southwest, and he began that fIrst
summer, ravenously absOlbing impressions of watersheds and
wildlife and history and culture as well as of board feet of
ponderosa pine. He led a reconnaissance party that cruised
timber along the route of a proposed road from Clifton to
Springerville that would have to clamber high over the
mountains because an earlier route up the valley of Blue River
had been washed out by severe flooding and erosion It was his
first introduction to the realities- of erosion in the Southwestern
environment that would shape so much of his thinking about
system-based management.
Leopold had trouble on that fIrst assignment, enduring a
months-long personnel investigation into charges of
incompetence and inefficiency in his handling of the
reconnaissance crew. But technically trained men were scarce
in those days; his superiors 4ccepted half the blame for his
missteps and gave him another chance. Having learned that the
selVice expected absolute adherence to administrative procedures
and the minutiae of management, he did so well on his second
chance that in 1911 he was appointed deputy supelVisor and a
scant year later supelVisor of the Carson National Forest in
northern New Mexico. He was age 25.
The course of Leopold's life was changed by an attack of
acute nephritis, a kidney disease, resulting from exposure on an
arduous trip to settle range disputes in April 1913. He nearly
died; and, given the state of medical opinion at the time, he had
to give up all hope of resuming the strenuous life of a forest
supelVisor in roadless mountain terrain. During eighteen long
months of convalescence, much of the time back home in
Burlington, Iowa, he had ample time to reflect on the meaning
of Forest Service work, and he shared some of his thoughts with
his compadres back on the Carson in a series of letters published
in the Carson Pine Cone, a newsletter he had founded:
After many days of much riding down among thickets of
detail and box canyons of routine, it sometimes profits
a man to top out on the high ridge leave without pay,
and to take a look around
Leopold had already learned that the Forest Service was
dedicated to its thickets of detail and its maze of routines. But
what was the measure of success in forest management? "My
measure," wrote Leopold, "is THE EFFECT ON THE
FOREST." Too often, it seemed to him, foresters fell into a rut
of routine, following the prescribed procedures without
considering the objectives. The rangers on the ground, as he saw
it, had the responsibility to apply the stated principles of forest
management in detail on particular areas and to monitor and
gauge their effect on the forest. To Leopold, the greatest
necessity was for "clear, untrammelled, and independent
thinking on the part of Forest Officers."
Gifford Pinchot's management philosophy is often termed
"scientifIc management." Knowing that Leopold and other
early foresters were trained in botany and silviculture that were
16
he had already tallied thirty mountain valleys in southwestern
forests and had found twenty-seven of them damaged or ruined.
Where several years earlier he had thought artificial controls
such as check dams, willow plantings, and plugging gullies
might be the answer, he was now much more intent on
understanding the "virgin state" of the watersheds and the
causes of erosion in order to detennine the appropriate objectives
of management.
When he compared obselVations in the field with Prescott
supelVisor Basil Wales and local rangers, he discovered that they
had significantly different inteIpretations of the history of the
area and hence different notions of what management should
seek to accomplish. Where Wales and his rangers thought the
grass cover had always been thin on the granite soils of the
Prescott and assumed, like most foresters of the day, that grazing
pressure was essential in order to hold down the fIre hazard of
brush, Leopold saw evidence in the fire scars of ancient juniper
stumps to conclude that fIre had been a recurring feature of the
virgin landscape. The grass cover had been much heavier and
the brush much thinner than at present, he surmised, owing to
grass fires and grass-root competition In his view, it was
overgrazing and trampling by cattle that had thinned the grass,
thus inhIbiting the fires and initiating both the destructive erosion
and the encroachment of brushfields that were now a severe fire
hazard. Leopold's inteIpretation, it should be noted, flew in the
face of virtually the entire coIpus of scientific dogma in the
Forest SeIVice of his day.
More to the point, differences in inteIpretation called into
question the objectives of management. "If the prime objective
is wood products," Leopold wrote, "we may continue to
overgraze, letting in the woodland and sacrificing watershed
values. If on the other hand the prime objective is watersheds,
we should restore the grass, which all the evidence indicates is
a better watershed cover than either brush or woodland.", So
struck was Leopold with the problem of determining the proper
objectives of management for particular areas that he sat down
to draft a paper on what he now called "Standards of
ConselVation" (1922c), using examples from the Prescott.
Here Leopold was dealing with the fundamental problem of
ecosystem management--the problem of specifying objective
standards of conselVation. But he never fmished the paper. In
fact, it ends in mid-sentence, just as he was tIying to explain
how one might use management plans to set the standards of
conselVation. Baird Callicott (1991) has suggested that perhaps
when Leopold got to this point he may have said to himself
"Who are you kidding?" and simply put down his pencil. He
realized that as long as Pinchot's utilitarian calculus prevailed
in the Forest SelVice, even the most sophisticated science would
not suffice to set objective standards. As Callicott put it, "The
paper self-deconstructs, so to speak."
Aldo Leopold would devote the remaining quarter century of
his life to working on the scientific and philosophical problem
of determining the objectives of conservation. His first
significant effort came several months after his inspection of the
Prescott in a paper titled "Some Fundamentals of ConselVation
Leopold declined transfers to other regions or positions in order
to prove he could master the job as chief of operations. He
proved it by designing and implementing a new, more systematic
method of forest inspection, complete with printed,
notebook-sized tally sheets for recording a myriad of details on
evetything from the cleanliness of outhouses to the condition of
grass and sod on pastures. In the area of fire control alone, his
tally sheets increased the number of obselVations required of the
inspector from twenty points under the old system to 165 points
in the new, all minutely classified as to subject and
administrative unit and designed to facilitate comparisons year
by year and forest by forest (LeoP'>ld, 1921).
Leopold's superiors in the Southwest and in Washington were
impressed-all those details, so ~fficiently catalogued. They
were particularly impressed with the first field test of the new
system, his 1922 inspection of the Gila National Forest. This
was the now-famous report in which he recommended a
wilderness area policy for the Gila and drew a red line on the
map to indicate the limits of motorized accessibility-the first
step toward designation of the Gila in 1924 as the prototype of
national forest wilderness areas. But it was not the wilderness
area proposal that attracted his superiors' attention to the Gila
report; rather, it was the painstaking detail and
comprehensiveness of the inspection itself.
Leopold considered his contributions to the development of
a forest inspection system for the Southwest to be "one of the
two or three points" in his own Forest SeIVice career that gave
him the greatest satisfaction. But, while his supeIVisors may
have been impressed by his systematic attention to detail-what
Leopold called the machinery of inspection-to him what still
mattered most was the results on the ground.
In an address on "Forest Inspection as Developed in the
Southwest" presented to the New York Forest Club (1924b) he
tried to grapple with the inherent difficulty of expressing what
he was tIying to accomplish in language that could as readily
be applied today to the difficulty of defining ecosystem
management:
It is always difficult to flatten out upon a printed page
a system of thoughts and facts which are concentric to
a single idea. Their relationships to that idea and to each
other are actually expressible only in three-dimensional
space. The flattening process inevitably severs many of
these relationships and leaves them at loose ends.
And then the kicker, whether for inspection or for ecosystem
management: " The only way to really see it is to watch it work
on the ground." Inspection to Leopold was a technique for
diagnosing local problems and monitoring the effectiveness of
management solutions.
Even as Leopold was developing his inspection system he
was also struggling, especially through his repeated forays into
forests along the Mogollon Rim, to understand the dynamics of
southwestern watersheds and to consider the implications of his
fmdings for conselVation policy and social values. These lines
of endeavor came together incrementally during his inspections,
but nowhere more so than on the Prescott in 1922. By this time
17
Madison, Wisconsin, then the principal research ann of the
Forest SeIVice. Never particularly happy in an institution devoted
to utilization of the tree after it was cut when evetything about
him made him interested in the forest as a living community,
he elected to leave the seIVice in 1928 to devote himself more
fully to his consuming interests in wildlife and conselVation
By any standard, Leopold had enjoyed an extraordinarily
successful career in the Forest SelVice. Despite some challenges
along the way, he had won the respect of colleagues up and
down the line for his unsweIVing loyalty to the agency, his
dedication to its mission of conservation, his obvious
administrative skills, his open, ever-questioning mind, and his
vision for the future. Because he never gave up tIying to move
the seIVice farther and faster than it was prepared to go, he
actually moved it farther than his colleagues at the time would
have thought possible. But he was under no illusions as to the
distance yet to be traveled.
The day before he retired from the Forest SeIVice in June
1928, the Service Bulletin (a house organ) published a response
by Leopold to a critic of his wilderness proposal that may stand
as his valedictoty challenge to the agency:
The issue is whether any human undertaking as vast as
the National Forests can be run on a single objective
idea, executed by an invariable formula. The fonnula in
question is: Land + forestry = boards. . . .
Whether we like it or no, National Forest policy is
outgrowing the question of boards. We are confronted
by issues in sociology as well as silvicu/ture,- we are
asked to show by our deeds whether we think human
minorities are worth bothering about; whether we regard
the current ideals of the majority as ultimate truth or as
a phase of social evolution; whether we weigh the value
of any human need . . . wholly by quantitative
measurements; whether we have forgotten that economic
prosperity is a means, not an end
To AIdo Leopold, the decision-at that time regarding
wilderness, today concerning ecosystem management-would
indicate whether the Forest Service was simply a bureau that
executed the laws, or "a national enterprise which makes
histoty." Naturally, Leopold challenges us to make histoty.
in the Southwest" (1923), in which he first sought to drnw his
obselVations about vegetation change and soil erosion into a
cultural and philosophical context. It was here that he first
expressed his intuitive sense of a living earth and addressed the
implications of conselVation as a moral issue. But again he did
not publish, whether because of uncertainty about the
philosophical argument or, just as likely, because of criticism
from colleagues about his analysis of the problem of erosion
Instead, he turned his fonnidable analytical and writing skills to
explaining more clearly the processes at work on southwestern
watersheds and the implications for management in a series of
papers that drew on his obselVations of forests along the
Mogollon Rim. In a Journal of Forestry article (1924a) titled
" Grass, Brush, Timber, and Fire. in Southern Arizona" he issued
a direct challenge to Forest SeIVice dogma: "Fifteen years of
forest administration were based on an incorrect interpretation
of ecological facts and were, therefore, in part misdirected." In
another paper, "The VIrgin Southwest and What the White Man
Has Done to It" (1927) he drew evidence from the accounts of
early explorers along with his· own uncanny skill at reading
histOlY backward in the land to sketch a vision of what the
Southwest had once been and hence what management might
aspire to restore.
Then in 1933 in his well known essay "The ConselVation
Ethic" he returned to the theme of conselVation as a moral issue,
this time thoroughly grounded in an understanding of the
dynamic functioning of interrelated elements of the system,
physical and biological, natural and cultural, through time. It
was this essay, significantly enhanced by a clearer statement of
the concepts of land health and the biotic community, that
became his celebrated essay "The Land Ethic," first published
in Sand County Almanac a year after his untimely death at age
61. And now it is his "land ethic" philosophy that is presumably
pointing the way to the future in Chief Robertson's directive on
ecosystem management.
If we would look for guidance as to the fundamental
objectives for ecosystem management, we could do no better
than to start with AIdo Leopold's famous dictum in "The Land
Ethic": "A thing is right when it tends to preselVe the integrity,
stability, and beauty of the biotic community. It is wrong when
it tends otherwise."
But if we would look for insight as to what might be involved
in actually implementing an ecosystem approach to management
on national forest lands, we might rather recall Leopold's
insistence on setting specific standards of conselVation for each
area through careful obselVation, historical study, and scientific
research and then monitoring and evaluating the effect on the
forest. Leopold's own experience as a forest inspector in the
1920s striving to comprehend processes of ecosystem change
along the Mogollon Rim in Arizona and New Mexico might be
our guide, informed by his even earlier call for "clear,
untrammelled, and independent thinking."
For reasons that have never been satisfactorily explained,
Leopold left the Southwest in 1924 to assume a new position
as associate director of the Forest Products LaboratOly in
LITERATURE CITED
Callicott, 1. Baird. 1990. Standards of conselVation: then and
now. Conservation Biology 4(3):229-232.
Flader, Susan L. 1974. Thinking like a mountain: Aldo Leopold
and the evolution of an ecological attitude toward deer,
wolves, and forests. Columbia: University of Missouri Press.
Flader, Susan L. 1976. Ecological science and the expansion of
our forest heritage. America's renewable resource potential:
the turning pOint (Proceedings: Society of American
Foresters): 108-120.
18
Flader, Susan L., and J. Baird Callicott, eds. 1991. The River of
Leopold, AIdo. 1924b. Forest inspection as developed in the
Southwest. Address to New York Forest Club, November 25.
Leopold Papers.
Leopold, AIdo. 1927. The virgin Southwest and what the white
man has done to it. Chapter II of" Southwestern game fields."
Leopold Papers. Revised version in RMG:173-180.
Leopold, Aldo. 1928. Mr. Thompson's wilderness. USFS
Service Bulletin 12:26 (June 25):1-2.
Leopold, AIdo. 1933. The conselVation ethic. Journal of
Forestry 31(6):634-643. RMG:181-192.
Leopold, AIdo. 1949. A sand county almanac and sketches here
Oxford University Press.
and there. New Yode
I
Meine, Curt. 1988. Aldo Leopold: his lifo and work. Madison:
University of Wisconsin Press.
Robertson, F. Dale. 1992. Ecosystem management of the
national forests and grasslands. Memorandum to regional
foresters and station directors, June 4.
Taylor, Frederick W. 1911. The principles of sCientific
the Mother of God and other essays by Aldo Leopold.
Madison: University of Wisconsin Press. [hereafter cited
RMG].
Leopold, AIdo. 1913. To the forest officers of the Carson, July
15, 1913. Carson Pine Cone (July). RMG:41-46.
Leopold, AIdo. 1920. Letter to mother, 15 May. Leopold Papers.
Leopold, Aldo. 1921. The D-3 notebook tally sheet: a
combination inspection outline and report. Topic #60, Fire
Conference, November 10. Leopold Papers.
Leopold, AIdo. 1922a. General inspection report of the Gila
National Forest, May 21-June 27, 1922. Leopold Papers.
Leopold, AIdo. 1922b. Report of general inspection of Prescott
National Forest, July 31-Septemger 1, 1922. Leopold Papers.
Leopold, AIdo. 1922c. Standards of ConselVation. RMG:82-85.
Leopold, AIdo. 1923. Some fundamentals of conselVation in the
Southwest. RMG:86-97.
Leopold, AIdo. 1924a. Grass, brush, timber, and fIre in southern
Arizona. Journal of Forestry 22(6):1-10. RMG:1l4-122.
management.
10
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