Fire in America

A Cultural History of Wildland and Rural Fire

Stephen J. Pyne

• Publisher: University of Washington Press
• Year: 2017
• ISBN:
  9780295805214
• Topic: Biological Sciences
• Subtopic: Ecosystems & Habitats
• Index: Biological Sciences

From prehistory to the present-day conservation movement, Pyne explores the efforts of successive American cultures to master wildfire and to use it to shape the landscape.

1NATURE’S FIRE

Gie me a spark o’ Nature’s fire,

That’s a’ the learning I desire.

—Robert Burns, 1786¹

And whereas it is generally conceived, that the woods grow so thick, that there is no more clear ground than is hewed out by labour of men; it is nothing so: in many places, divers acres being clear, so that one may ride a hunting in most places of the land, if he will venture himself for being lost: there is no underwood, saving in swamps and low grounds that are wet . . . for it being the custom of the Indians to burn the woods in November. . . .

—William Wood, New England Prospects, 1634²

It is the peculiar quality of fire that it is both natural and cultural. Nature gave fire to man, presented an arena for its use that was to some extent adapted to fire, and established limits, based on fire’s behavior and effects, to its potential exploitation by mankind. Man’s ability to create and control fire with relative ease makes his relationship to fire unique vis-à-vis those other potentially destructive eruptions of energy, such as windstorms and floods, which, like fire, cannot be separated from the landscape. An understanding of fire behavior and fire ecology is basic to any comprehension of how fire has functioned historically and how policies for its management must be shaped. Its origin in lightning, moreover, makes fire an essential component of any environment that mankind purports to manage in a natural or wild state.

The fire history of the northeastern United States is a particularly apt preamble to the fire history of the nation. The region presents a historical kaleidoscope, previewing the problem fire types, the range of fire regimes, and the responses typical of the American experience. In its coal fields are the residue of ancient geologic fires. In its rich accounts of European settlement are excellent descriptions of Indian fire practices. It was the first region to experience agricultural reclamation and logging on a grand scale and the first to undergo industrial counterreclamation, that is, the abandonment and transformation of arable land. The Dark Days recorded in eighteenth-century literature foreshadowed the spectacle of holocausts to come. The 1825 Miramichi fire was the first conflagration to enter into the historical chronicle of great American fires. The 1947 Maine fires were among the first to suggest the volatile mixture of wild and urban areas created in post–World War II America. The New Jersey fires of April 1963, sweeping over more than a quarter of a million acres, testified to the endurance of one of the hardiest fire climax biotas in North America. The debate in the 1970s over wilderness fire management in Maine’s Baxter State Park, shows the modern paradox that wilderness, like fire, is both natural and anthropogenic.

From the Northeast came many of the fundamental experiments in organized fire protection. New York, in particular, early enacted fire codes to regulate the agricultural uses of fire and established a rural fire warden system to protect against damaging escapes. The creation of the Adirondacks Reserve in 1885 set an important example for fire patrols not only in the Northeast but also in the Lake States and even the Far West. At Cornell and Yale the first schools of professional forestry were endowed. Fires in 1903 and 1908 had national repercussions in the campaign for organized fire control and conservation. The Weeks Act of 1911, by allowing the creation of national forests east of the Mississippi, helped to extend the example of the Adirondacks preserve throughout the Appalachians. Following the disastrous 1947 fires, the northeastern states set up the first interstate fire compact, a model for civil defense and rural fire protection throughout the nation. The fire history of the Northeast was, as often as not, a prototype for what was to come.

ELECTRICAL FIRE: A NATURAL HISTORY OF LIGHTNING FIRE

The agent by which fire was first brought down to earth and made available to mortal man was lightning. To this source every hearth owes its flames.

—Lucretius, De Rerum Natura³

This is the forest primeval.

—Henry Wadsworth Longfellow, Evangeline⁴

I

In the mid-1770s William Bartram undertook the travels that made him famous as a naturalist and littérateur. Somewhere in the Carolinas he “found friendly and secure shelter from a tremendous thunderstorm, which came from the northwest and soon after my arrival began to discharge its fury all around.” It was “an awful scene; when instantly the lightning, as it were, opening a fiery chasm in the black cloud, darted with inconceivable rapidity on the trunk of a large pine-tree, that stood thirty or forty yards from me, and set it in a blaze. The flame instantly ascented upwards of ten or twelve feet, and continued flaming about fifteen minutes, when it was gradually extinguished by the deluges of rain that fell upon it.”⁵ Electricity, it has been observed, “came on the eighteenth century as unexpectedly as nuclear power came on our century.”⁶ Bartram’s naturalistic description of lightning fire was complementary and nearly contemporary to Benjamin Franklin’s more physical analysis of “electrical fire.” What each man shared was a long-embedded cultural association of lightning with fire.

Electrical fire operated on the earth’s surface as soon as an atmosphere evolved and vegetation appeared. The relation between lightning and life may be even more intimate. Work by Oparin, Urey, and Miller has suggested that lightning may have catalyzed the earliest organic compounds out of a “primordial soup” of chemicals. Whatever the ultimate origin of the relationship between life and lightning, the antiquity of this association is impressive. E. V. Komarek has observed that “it has become apparent that lightning fires are only one illustration of the ecological effects of lightning and that lightning itself is only one example of a basic natural and ecologically important component of the universe: electricity.”⁷

Lightning restores electrical equilibrium to the earth. Because air is a poor nonconductor, some electricity constantly leaks to the atmosphere, creating an electrical potential. When the potential is great enough, electricity moves back according to the gradient. During a thunderstorm, the gradient becomes very steep, and the electrical potential discharges as lightning. The discharge may move between any oppositely charged regions—from cloud to earth, from earth to cloud, or from cloud to cloud. It was calculated as early as 1887 that the earth would lose almost all its charge in less than an hour unless the supply were replenished; that is, on a global scale, lightning will discharge to the earth every hour a quantity of electricity equal to the earth’s entire charge. Thunderstorms are thus an electromagnetic as well as a thermodynamic necessity. It has been reckoned that the earth experiences some 1,800 storms per hour, or 44,000 per day. Collectively, these storms produce 100 cloud-to-ground discharges per second, or better than 8 million per day globally. And these estimates are probably low. The total energy in lightning bolts varies greatly, but about 250 kilowatt hours of electricity are packed into each stroke—enough “to lift the S.S. United States six feet into the air.”⁸ Almost 75 percent of this total energy is lost to heat during discharge.

Two types of discharge patterns are commonly identified: the cold stroke, whose main return stroke is of intense current but of short duration, and the hot stroke, involving lesser currents of longer duration. Cold lightning, with its high voltage, generally has mechanical or explosive effects; hot lightning (also known as long-lasting current, or LLC), with higher amperages, is more apt to start fires. Studies in the Northern Rockies suggest that about 21 percent of all lightning moves from cloud to ground, of which about 20 percent is of the LLC variety. That is, in the Northern Rockies about one stroke in 25 has the electrical characteristics needed to start a fire. Whether it does or not depends strongly on the object it strikes, the fuel properties of the object, and the local weather. Ignition requires both heat and kindling. Lightning supplies the one with its current and occasionally finds the other among the fine fuels of rotton wood, needles, grass, or dustlike debris blown from a tree by the explosive shock of the bolt itself.⁹

The consequences of lightning are complex. Any natural force of this magnitude will influence the biological no less than the geophysical environment, and the secondary effects of lightning are significant to life. Lightning helps to fix atmospheric nitrogen into an organic form that rain can bring to earth. This may be important in regions of heavy lightning fire, because fires tend to volatilize organic nitrogen. In areas of heavy thunderstorm activity, lightning can function as a major predator on trees, either through direct injury or by physiological damage. In the ponderosa pine forests of Arizona, for example, one forester has estimated that lightning mortality runs between 0.7 and 1.0 percent per year. (The burned-area objective for fire control, by contrast, is 0.1 percent per year.) Other researchers have placed mortality as high as 25–33 percent. For southern pines, the figure may be even steeper. A study in Arkansas calculated that 70 percent of mortality, by volume, was due to lightning. These figures describe only direct injury, primarily the mechanical destruction of branches and bole; the other major causes of mortality—insects, wind, and mistletoe—are likely secondary effects brought about in trees weakened by lightning. All of these effects, in turn, may be camouflaged by fire induced by lightning.¹⁰

The process of “electrocution” is increasingly recognized. Lightning scorch areas of between 0.25 and 25 acres have been identified among southern pines in Georgia, Douglas fir in the Northwest, chestnuts in Virginia, saguaro cacti in Arizona, peat swamp forests and mangroves in Malaysia, and cabbage palms in Florida. Nor is the process limited to trees: it has been documented for grasses, tomatoes, potatoes, cabbages, tea, and other crops. Long attributed to inscrutable “die-offs” or to infestations by insects or diseases (often a secondary effect), such sites are now recognized worldwide as a product of physiological trauma caused by lightning. Interestingly, these effects are most readily visible in subtropical or tropical regions where lightning fire is rare and cannot mask the electrical effects of lightning alone. This may explain why, in areas where a lightning fire type, such as the southern pine in Florida, has been converted to crops or citrus groves, lightning kills are better recognized. Even where trees have been converted to barns, barn fires testify to the effectiveness of lightning predation.

The most spectacular product of lightning is fire. Except in tropical rain forests and on ice-mantled land masses like Antarctica, lightning fire has occurred in every terrestrial environment on the globe, contributing to a natural mosaic of vegetation types. Even in tropical landscapes lightning bombardment by itself may frequently be severe enough to produce a mosaic pattern similar to that resulting from lightning fire. Lightning fires have ignited desert grasslands in southern Arizona, tundra in Alaska, chaparral in California, swamplands in the South, marshes in the Lake States, grasslands of the Great Plains, and, of course, forests—especially conifer forests—throughout North America. Though the intensity and frequency of these fires vary by region, their existence is undeniable.

So is their persistence through geologic time. Fused inorganic tubes caused by lightning strokes to the ground, called fulgurites, are abundant in many portions of the earth. Ample evidence of fossil fires, called fusain, lies buried in the coal beds of all the coal-forming periods known to geology. For more recent geologic times, evidence of ancient fires can be found in peat. Lightning and fire scars have been identified on petrified trees. The geologic record even finds collaboration from the genetic record. Komarek has observed that “the antiquity of fire seems apparent in that the most ancient of tree families, such as the conifers, and the apparently oldest genera of grasses, such as Aristida, Stipa, Andropogon, etc., have the greatest concentration of those genes responsible for resistance and adjustment to a ‘fire environment.’ ” Komarek has also suggested that intense lightning bombardment (and, indeed, intense fire) might act as a mutagenic agent, accelerating fire adaptability in zones of heavy lightning fire.¹¹

The contemporary geography of lightning and lightning fire is equally impressive. Lightning behaves like other natural eruptions of energy. It exhibits a large number of discharges but a relatively small number of really intensive displays—a pattern that is repeated by lightning fire and by fire behavior. Komarek has tried to demonstrate some typical meteorological conditions that can distribute lightning to various regions of the United States. In one study he traced the passage of a cold front from Canada to Florida from April 30 to May 16, 1965. Using data only from national forests and grasslands (except for Florida, where full records were available), he identified 47 lightning fires—6 in South Dakota, 5 in Tennessee, 4 in Virginia, 3 in Nebraska, 2 in Georgia, 1 each in Michigan, West Virginia, and North Carolina, and a whopping 34 in Florida.¹² In another system, the summer monsoon typical of the Southwest, some 536 lightning fires were reported in Arizona and New Mexico between July 7 and July 16, 1965. Between 1940 and 1975 a total of 59,518 lightning fires occurred on the national forests of the Southwest, 79,131 on the forests of the Rocky Mountains, and 88,680 on the forests of California and the Pacific Northwest.¹³ Though the effect of lightning fire may be masked when considering a continent or when amalgamating it with all fire starts, the local effect may be considerable. The evolutionary consequences are undeniable.

Lightning, however, is but one component of climate, and thunderstorms alone are inadequate to ignite fires. The heaviest lightning activity globally is in the tropics, where natural fire is rare; the lightest lightning loads are in the upper latitudes of the boreal forest, where natural fires, though infrequent, can reach conflagration size. In the summer of 1957, for example, some 5 million acres burned in the interior of Alaska, largely due to lightning. The most effective fire starters are “dry” lightning storms—thunderheads from which little precipitation reaches the ground and which commonly occur after droughts or dry seasons. The largest episode on record came during a 10-day period in June 1940, when 1,488 lightning fires broke out in the Northern Rockies. This is the heaviest known concentration by a factor of two; but from 1960 to 1971 the Northern Rockies and the Southwest regions of the Forest Service witnessed six separate 10-day outbreaks of 511 to 799 lightning fires each. Dry lightning storms occur in the Northern Rockies and Pacific Northwest several times each decade, whereas they are almost annual events in the Southwest (during the spring) and in Florida (during the winter). Major episodes are rare, of course, but as with floods, windstorms, and earthquakes, proportionately more change results from these larger eruptions than from the cumulative effects of minor events.

The appropriate lightning must interact, in turn, with other environmental conditions before fires can result. Natural fire regimes expand and recede, like the ebb and flow of glaciers, with fluctuations of climate and the effect of climate on fuels. Even with man’s capacity to simulate lightning through ingenious ignition devices, there will be no fire unless weather and fuel are right. In areas somewhat resistant to fire it is often necessary to create conditions equivalent to drought before burning can begin. This can be done, for example, by draining swamps or marshlands, by killing or dessicating vegetation prior to ignition, or by altering microclimates through fuel type conversions.

Lightning fire brings a persistent and perhaps unalterable number of fires to the total fire load of a region. As a manifestation of climate, it is the basis for fire ecology, for fire behavior, and for the possession of fire by man. There are reports of fires starting from other ignition sources in nature—from branches rubbing together, stones striking against each other, volcanic discharges, and even spontaneous combustion (most evident in caves). But these sources cannot account for the widespread adaptations to fire by natural communities or for the universal capture of fire by man. The evolutionary reality of natural fire is an inescapable fact, and lightning fire is the philosopher’s stone for nearly all contemporary thinking about the objectives of wildland fire protection.

The apparent rarity of lightning fire is a statistical phenomenon camouflaged by the ubiquity of anthropogenic fires. When it occurs, however, it can have tremendous impact. Many of the most stubborn and costly fires of recent years have been the result of lightning, often of multiple lightning fires in remote areas that burned together: the Alaska conflagrations, 1957; the Sleeping Child fire, Montana, 1961; the Elko fire, Nevada, 1964; the Glacier Wall, Trapper Peak, and Sundance fires, Montana, 1967; the Swanson River fire, Alaska, 1969; the Wenatchee fires, Washington, 1970; the Carrizo fire, Arizona, 1971; the Seney fire, Michigan, 1976; the Baxter Park fire, Maine, 1976; the Marble Cone and Hog fires, California, 1977; the fire complexes in southern Arizona and interior Idaho, 1979. Man-caused fires occur in areas accessible to people, which makes the fires equally accessible to control forces. Lightning fires are more randomly distributed, and remote fires, of whatever size, escalate suppression costs rapidly.

The relationship between lightning and life, like that between fire and life, has affected man no less than other elements of the biota. Lightning has been a persistent predator on man and his stru...