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Land of Contrarities

Drought, dry seasons, and, more than all—that deadliest weapon of the tyrant—the bush-fire, reduces and selects the life of the country.

—W.H.L. RANKEN, The Dominion of Australia (1874)

The aspect of the country was fearful. Brown, burnt-up, and sweltering under a broiling sun! … Imagine all the trees and scrub high above your head blazing—all the ranges, as far as the eye can reach, one mass of smoke and fire.

—MARCUS CLARKE, letters

IN ITS ORIGINS, ancestral Australia was all but indistinguishable from the rest of Gondwana. Its biota was similar, if not identical; its climate was mild and wet; its seasons, invariant. But the breakup of the supercontinent had led, inevitably, to changes that demanded, and forged, new identities. Leaching, drying, and burning, each in turn and with cumulative impact, worked over Australia’s Gondwanic legacy. The tempo of disturbance quickened and beat to irregular rhythms. Isolation ensured that recolonization was negligible, that new biotas would have to evolve from the inherited stocks. The Great Upheaval installed to dominance a dramatically different biota. A second revolution within the emergent scleroforest furthered and confirmed that transformation. After Homo infiltrated the continent, the process was irreversible. Out of Gondwana rainforest emerged, through these trials, Australian bush.

By the time Europeans arrived, the bush presented an inverted world, a parallel universe. It was as if a second ark had escaped the Flood, as though a whole continent had passed through an enchanted looking glass. Compared to northern Europe, Australia exuded the alien, the hostile, the sterile, the bizarre. François Peron alluded to “whimsical freaks of Nature” that defied attempts at scientific understanding. James O’Hara disparaged a Nature that apparently “indulged in whim,” such that nothing—neither animal nor vegetable—resembled anything anywhere else. Charles Darwin mused that here at the antipodes “an unbeliever in everything beyond his own reason might exclaim, ‘surely two distinct Creators must have been at work.’” Marcus Clarke invoked a “Weird Melancholy” to conjure the spirit of the bush, later softening that cry with an appeal to “read the hieroglyphs of haggard gum-trees.” Perhaps the most famous denunciation, already couched in sardonic tones, was the declaration of an anonymous colonial poet of the 1850s:

There is a land in distant seas

Full of all contrarities.¹

The nature of Australian exceptionalism was difficult to identify precisely. It was there in the bush, certainly, though the bush echoed bits and pieces of other Gondwanic lands. It meant coming to grips with miserable soils, aridity, desert winds. And, everyone agreed, it involved bushfire. Whatever elements led to the bush, fire integrated and accelerated, like a flask of chemicals held over a Bunsen burner. By geologic standards, the bush was a sudden invention, kindled almost instantaneously from drying Gondwanic tinder and the flint of Homo sharply striking the continent. However the bush defined Australia, so fire defined the bush. In ways both obvious and obscure, the land of contrarities was a land of fire.

AN EVER-LIVING FIRE

The geographical border that so sharply segregates rainforest from scleroforest has a temporal analogue in the veritable explosion of fire that raged across Australia during the Holocene. Fire was abrupt, ubiquitous, grasping. It insinuated itself into malleable biotas. It welded the biotic pieces into a dynamic whole. Not fire alone but its versatility—its ability to interact with the other elements of the bush—established its importance. Fire dominated the dynamics of the Australian bush as fully as Eucalyptus dominated the composition of its forests and woodlands.

This was not inevitable. Had Australia rafted into the tropics at a different rate, had its initial floristic composition not included so many scleromorphs, had Acacia replaced the ancestral Eucalyptus as part of the original Gondwanic ark, had Australian soils experienced more general rejuvenation, had other species leaked across its borders, the story might have turned out differently. Instead fire seized the core, not merely recycling habitats and nutrients but diverting the whole biota into new evolutionary pathways from which recovery might be impossible. Fire integrated the elements of the bush, and anything that affected the presence of fire ramified throughout the bush. Above all, fire bonded the bush to humans. The bush could not be understood without its distinctive, singular fires.

But fire did not by itself render Australia a land of contrarities: fire is everywhere on the planet. The evolution of the Earth into a fire planet has paralleled the evolution of life. Marine life gave it an oxygenated atmosphere; terrestrial life packed its surface with fuels accessible to oxygen; lightning supplied spark to both life and fire. Since the time these elements first came together, the Earth has burned. Terrestrial life has evolved in the presence of fire. The earliest coal beds are laced with fusinite, the charcoal of ancient fires. Heracleitus was right, “This world … was ever, is now, and ever shall be an ever-living fire, with measures of it kindling, and measures going out.”²

Fire has been everywhere on the Earth’s lands. Huge conflagrations have swept the boreal forest on a cycle of centuries. Temperate forests burn on more irregular rhythms, with greater variations in intensity. Conifer forests throng like chemical kindling, ready to erupt into fire. Thick lenses of charcoal underlie the Amazon Basin. Fire on the order of 4 million hectares gutted the normally dripping jungles of Borneo after several years of drought. Tropical savannas burn almost annually. Fire invades temperate grasslands routinely, sometimes yearly. The grasses of wetlands burn. Tundra burns. Peat burns. Swamps drained by drought burn. Deserts, suddenly flush with life after rains, burn. Cropping out from the ice of Antarctica are coal seams charged with pyrofusinite. The fires in each of Australia’s climates can be matched, and often exceeded, by fires elsewhere or in the past.³

Likewise, the adaptations to fire regimes that Australian organisms display, while marvelous, have analogues among the flora and fauna of other continents. Warm-season grasses everywhere show a similar suite of traits to protect against grazing, drought, and fire. The longleaf pine of the American South experiences a “grassy” stage in its early life cycle that makes it susceptible to burning; if not burned, it is vulnerable to the fatal blue spot fungus as an adult. The seeds of Sequoia germinate best in warm, ashy soil, exactly the conditions that prevail after an intense fire. Several North American pines—lodgepole and jack, among them—feature serotinous cones that open only when heated; a flash fire through the canopy exactly serves this purpose, and the exposed mineral soil is quickly saturated with descending seeds; the forest recovers as an even-aged stand. Other organisms rally around these patterns—the endangered Kirkland warbler thrives only in jack pine of a certain age class. Evergreen sclerophylls exist in all Mediterranean-climate sites. The chamise of California, for example, prepares itself to burn as it ages. By age twenty it steadily increases the proportion of dead wood to live in its crown; virtually all new growth is available as fuel; a woody understory begins to form; the oily leaves, drained of moisture by seasonal or secular drying, blaze like blow torches.

The list goes on. And on. Combustion is too much a part of the biological fabric of the Earth for Australia to have created a monstrous incongruity of fire. The fire regimes of ancient Australia echoed those found elsewhere among its Gondwana cognates. In the deserts fire followed episodes of unusual rainfall. In a pattern that mimicked the central Australian fires of 1974–75 extensive fires swept the Kahalari in the early 1980s after a bout of exceptional precipitation. The border between grassland and desert has ebbed and flowed with the movement of storm tracks and monsoonal winds. Fires have crept into the Sahara with the encroachment of grasses; in Pleistocene times, when the region was much wetter than at present, fires burned grasslands in what is now sanddune and stone. The border of rainforest in eastern India, equatorial Africa, and Amazonia is all but universally inscribed by fire. Tropical savannas burn almost annually. More temperate grasslands burn only slightly less often, a shifting cultivation by fire of scattered trees, shrubs, and grass. The Mediterranean-climate regions of modern Gondwana are notorious as fire environments, fluffed with scleromorphic vegetation, kiln-dried under a baking sun, and subject to outbreaks of foehn and sirocco winds that drive fire before them like a flaming avalanche. Fire is everywhere, differentiated into regimes but never truly absent.

Yet Australia was incontestably different, and fire served as a catalyst for that difference. By the end of the last glacial epoch the island continent moved from the triumvirate that had governed Old Australia—impauperate soils, aridity, lightning fire—to the triumvirate that would shape its succeeding Australias—eucalypts, humans, anthropogenic fire. Old Australia felt that impact first in those regimes where the new elements most intersected, its savannas and its Mediterranean-climate lands. Its ever-living fire was a means of transition, the point through which, like a crystal lens reversing everything within its field of vision, the landscape inverted.

FIRE FUSE: THE AUSTRALIAN SAVANNA

Australia’s savannas link it with a global biogeography. Tropical savannas are extensive in Africa, South America, Mesoamerica, India, and Southeast Asia; temperate savannas, often enormous, border the pampas, veldt, steppes, and prairies of the major continents. The essential ingredients are grasses, a seasonal cycle that brings sufficient moisture to grow fuels yet passes through a dry phase, and fire. In the tropics and subtropics, the border between savanna and rainforest is abrupt and, except in droughts, unbridgeable by fire. In more temperate lands, wooded enclaves thrive in wet river bottoms or on the lee side of rocky outcrops, wherever fires cannot routinely penetrate. When fires are excluded, forest reclaims grassland. Apart from these generic traits, however, the Earth’s savannas reflect local biotic materials and their history.⁴

It is not clear how the savannas originated. Grasses first appear in the geologic record during the Eocene (50 million years ago). Associated forbs and composites materialize in the Miocene, roughly coincident in Australia with the onset of the Great Upheaval. To what extent this grass mélange constituted a grassland is difficult to determine; almost always there is a concurrent record of trees, either conifer or hardwood. Probably the associated grasses were elements of a forest understory. Then, as climates dried, as drought appeared in seasonal rhythm, as fire increased in prominence, grasses replaced trees as a dominant flora, and forests evolved into savannas. In some places grassy fuels massed; elsewhere they fingered outward into surrounding biotas. Regardless, they became an enormous fuse that carried fire throughout Old Australia.

What complicates this simple scenario is the origin of that critical fire. In historic and prehistoric times, the vast proportion of ignitions has been anthropogenic—so much so that many observers have even doubted the competence of natural sources. In part this reflects how massive human intervention has been: humans have preempted natural fire, or through their fire practices have restructured its vital core. In part, however, contemporary observations speak to a biota that now exists under a climate different from that under which it was created.

The savanna exists in dynamic equilibrium between a tidal climate that drives it alternately to grassland or forest. Lightning fire assisted, and anthropogenic fire arrested, those natural oscillations. The contemporary savanna is likely a human artifact, a biotic edifice sculpted by anthropogenic burning. Fire is not merely something that occurs in a savanna: it is a prime mover of savanna dynamics. To be effective, the burning must be regular and at short intervals for which, as Carl Sauer asserts, “man is the competent agent.” ⁵

Yet where humans are removed, where the climate is sufficiently ambiguous to support either regime in the absence of hominids, natural ignitions are evident and often potent. Lightning at the onset of the wet season can be effective at kindling large fires. When combined with drought, grass-fueled fires may break through the microclimatic barrier that segregates grassland from forest and raze even rainforest into prairie. The rhythms, however, are irregular. The geography of a natural savanna is a swale of patches, of lands lost and reclaimed as drought and rain alternately flame and quench grassy and woody fuels. What humans do is to overwhelm, redirect, and regularize that fire regime; and particularly where fire is used with other forms of land use such as herding or swidden agriculture, to extend their mutual dominion. Human firesticks can reorganize the geography of fire much as irrigation can reorganize the natural geography of water and extend the realm of agriculture. With routine anthropogenic burning, savanna can even defy climatic changes that, if left untrammeled, would push the biota into forest.⁶

Its fire bond with humans made the Australian savanna more than one biota among many. It opened Old Australia to Homo. It seems likely that hominids emerged on an African savanna swept by lightning-caused and volcanic fires. Alone among organisms humans learned to use fire actively, and they learned those practices on grasslands. It is likely that humans entered Old Australia when the Sahul was a grassy plain that not only defined a physical corridor by which to travel but gave entree into the critical dynamics of the emerging Australian ecosystems—a biotic corridor, a fuse for anthropogenic fire. Fire created conditions attractive to humans, and humans reciprocated by introducing more fire.

CONCENTRATED FIRE: AUSTRALIA’S MEDITERRANEAN LANDS

Its Mediterranean landscapes are Australia’s other special environment. Like its savannas, they are local expressions of a global feature. They come and go with climatic oscillations. They are recent, dating from the Pleistocene. And they are at least partially anthropogenic, their histories inextricably tied to humans and their biological allies. Unlike the savanna, Mediterranean lands are not corridors but collecting basins. They are less a frontier, advancing and receding, than a crossroads where many biotas converge, claim distinctive niches, and settle into a complex caste system of subbiotas. If savannas are fuses, the Mediterranean landscapes are the explosives to which they lead. Australia’s Mediterranean and peri-Mediterranean regions contain its most heavily stocked biotas, the densest populations of humans, the fullest congregation of fire practices, and the most violent fires.

By area less than 5 percent of the Earth’s land surface, the Mediterranean-climate lands fall into five terrains—the Mediterranean Basin proper, South Africa, northern Chile, Southern California, and the southern perimeter of continental Australia. Each terrain exhibits mild wet winters and long dry summers. Their common geographies include a littoral, a seasonal pattern of cold offshore currents, mountains, and recurring disturbances. Interestingly, four of the terrains border fragments of Gondwana. Mediterranean California (ever the exception) overlies a sliver of the Pacific plate that is only coincidentally, ephemerally attached to the North American plate. Their common Gondwanic heritage helps to account for the apparent dominance of evergreen scleromorphs that trace their evolutionary origins to tropical or subtropical floras; they mingle the moist with the arid, the tropical with the temperate. Their complex physical geography makes possible, in turn, a complex geography of life, the mosaic of microclimates sustaining a mosaic of microbiotas.⁷

Mediterranean ecosystems are chocked with new and relict species—a living palimpsest stuffed with biotic glosses and interlinear subtexts. The border between floral types is abrupt. A change in climate, land use, or fire patterns can deflect the system into any of several subbiotas. At their core are shrubby scleromorphs—chamise and chaparral in California; maquis, garrigue, macchia, and phrygana in the Mediterranean; renosterveldt and fynbos in South Africa; matorral in Chile; mallee in Australia. Each label subsumes a host of species. If precipitation increases, scrub matures into mountain forests of evergreen scleromorphs or, if they front Laurasian lands, of drought-toughened conifers. If precipitation decreases, scrub surrenders to a subdesert of low, dispersed shrubs. If soil fertility improves, grasses thrive. If fertility degenerates, heath flourishes. Each terrain pieces together a mosaic that balances, on small sites, these competing pressures.

All share, too, a history of human manipulation. Humans are intimately implicated in the maintenance, if not the origins, of the Mediterranean lands, all of which emerged during the Pleistocene under the combined impact of climate, biotic revolutions, and humans. Mediterranean soils are either impauperate or prone to degradation; their constituent species are survivors—tough, weedy, thriving on disturbance, perfect associates for humans; and microclimates are ideal for fire. Burning can occur over a long dry season, droughts blanch the land frequently, and while large burns are possible, the rugged terrain compartmentalizes fire, giving it a specificity not unlike the fuels upon which it fed. Such an environment humans found congenial—as they cut, grazed, and fired and so altered biotic composition, induced soil erosion, and upset water regimes.

Anthropogenic fire was everywhere present and everywhere absorbed. Yet, while formative, it was not always mandatory. In Chile, for example, lightning fire is infrequent (less than 2 percent of all starts), and it appears that the scleromorphs took over the landscape without fire driving them into ascendancy. But because these environments were so susceptible to fire, they were especially susceptible to human manipulation, and once colonized, humans indelibly branded them with anthropogenic fire, typically associated with other practices such as hunting, grazing, clearing, farming, and war. So ubiquitous has anthropogenic fire become that it is difficult to reconstruct what a fire regime without human influence might look like.⁸

There were of course differences among the Mediterranean environments. Chile lacks the violent winds that power large fires in the cognate lands—the bora, mistral, and sirocco that sweep the Mediterranean Basin; the Santa Ana and Mono of Southern California; the desert winds and southerly burster of southeastern Australia. But large or small, fires were in Chile, as they were in the other sites. The Mediterranean Basin was notorious as a tinderbox, constantly burned in association with human land practices. The west Mediterranean and islands like Corsica and Sardinia continue to be known, because of their fires, as the “red belt.” Southern California was fired until it resembled a burnt-out case. Veldt and fynbos fires greeted the first settlers of Cape Town. The Chilean landscape continued a pattern of burning that extended from the lowland llanos to the lofty altiplano. Australia was rimmed with smoke, seared with episodic conflagrations. Whatever the natural state, the condition of the Mediterranean terrains from the time of human colonization has been one of chronic fire.

Australia’s Mediterranean terrains possess some distinctive features. They are more influenced by intermittent summer rains, less controlled by a weaker ocean current. Their soils are among the oldest and most degraded, constantly pushing the system toward heath and scrub. With fewer mountains, the terrains display fewer niches. Their shrub component—mallee—is high, between half and three-quarters of all the biomes assimilated. They have experienced a far more intense isolation because they have been severed from large continents that could restock the site with new species. Instead they have been exceptionally dependent on flora and fauna introduced by humans, often from other Mediterranean terrains. While the number of eucalypts included among the mallee is comparable to the total number of woody species found in cognate terrains, the mallee all derive from a single genus, and its genetic variability is inherently less than the others.

As with its savannas, however, the decisive difference between Australia’s Mediterranean terrains and those elsewhere derive from their human history. In the southeast, particularly, fire practices congregated. The Aboriginal occupation of Australia subjected the Mediterranean terrain to elaborate foraging and burning, but without farming, land clearing, herding, and the massive introduction of exotic flora and fauna that grossly complicated and magnified the effects of anthropogenic fire elsewhere. That came with European colonization. Europeans, in fact, arrived already long experienced in the settlement of Mediterranean-type terrains, and with remarkable persistence they sought out one Mediterranean landscape after another.

And with good reason. It was in the Mediterranean Basin that Western civilization honed its agricultural techniques, selected its preferred species of plants and animals, accumulated the experience that would make possible the colonization of the remaining Earth’s Mediterranean terrains, all prime sites for human habitation in part because of the ancient bonds developed in the model region. Thus Australia quickly established important ties with South Africa, Chile, and California, and through Britain with the Mediterranean Basin as a source of crops, livestock, irrigation expertise, and human immigrants. In return, Australia exported eucalypts.

As with savannas, so also Mediterranean lands became points of entry for human colonizers. If the Aboriginal march through Sahulian savannas recapitulated the origins of Homo, European colonization into Australia’s Mediterranean terrains recapitulated the origins of Western civilization. In both instances, those biotas influenced Earth history far beyond what their minuscule land areas suggested was possible. It was no accident that both streams of colonists sought out exactly those Australian lands most amendable to anthropogenic fire. Landscapes that had known fire apart from humans now found themselves ruled, in good measure, by human fire.

“A FIRE HUGE IN IMAGINATION AS THE WORLD”

The Australian bush was far from completed when the first humans arrived, and its antipodean qualities only partially confirmed. It shared ancestral origins with other Gondwana flora. Its biotas and subbiotas had analogues elsewhere. Other Gondwanic shields had leached soils, some on a massive scale. Seasonal drought afflicted every continent and most islands. The Sahara and the Kalahari deserts in Africa, the Atacama in South America, the Thar in India—all developed on Gondwana cratons in roughly the same latitudes as Australia’s Red Centre. Excluding only the ice sheets, free-burning fire was universal. Everywhere fire performed similar functions and obeyed the same laws of physics. In Mediterranean terrains fire was routine, sometimes explosive.

Yet the landscape of Old Australia was different, too. It contained some unique elements, combined in unique ways, and animated by fire into a unique presence. The universality of Eucalyptus is a striking phenomenon. Other lands had evergreen scleromorphs that dominated a biota, many such genera of ancient tropical or subtropical origins and all inured to fire. But nowhere else did one genus dominate across nearly all the wooded environments of a continent. In Australia gums define the character of the bush from tropical savanna to Mediterranean shrubland to mountain forest. Eucalypts tyrannize the entire spectrum of wooded lands, excepting only the mulga mélange. It is as though, in North America, chamise (Adenostoma) grew not only as a shrub but as a tree, as though it were supreme not only in Southern California but in the Everglades and the Rocky Mountains and along the watercourses of the High Plains, as though forests of pine, spruce, fir, oak, and hickory were all banished or shrunk into vestigial relicts and replaced by species of chamise. While the variety within the Eucalyptus alliance is staggering, there remains a commonality of history and behavior that has indelibly equated the bush with the eucalypt and stamped that bush with a distinctive monotony. When the explorer John Oxley despaired that “one tree, one soil, one water, and one description of bird, fish, or animal prevails alike for ten miles and for one hundred,” he was hardly accurate, but Australia did show a remarkable singularity for which its singular addiction to fire is partly accountable.⁹

The pieces that made up the bush came together in a unique context. Australia combined unusual size with extraordinary isolation. Until humans arrived, there were few exchanges with other lands. Australia imported little and exported less. Environmental stresses acted wholly on indigenous materials. Particularly in the southeast, winds, soils, precipitation, and biotic reserves concentrated the bush into a dense, volatile mosaic boiled down into a distillate by periodic fire. By Pleistocene times—as climatic and biotic disturbances became more violent and routine—Homo arrived with flickering firesticks to impose a complex economy of hunting, foraging, and gathering. For this task fire was an indispensable and universal tool. Initially it affected those landscapes that were especially susceptible to anthropogenic fire, then spread like an oil slick into every niche it could find.

In the process fire became more than a phenomenon: it asserted a presence. In Australia fire had a relentless intensity and a continental scale. It was pervasive, persistent, singular. It magnified, telescoped, and simplified the bush. Fire had touched other continents, but it branded Australia. The contrast with New Guinea, once joined to Australia across the Sahul plain, is instructive. Here soils were remade or freshened by volcanism; the climate was spared aridity, except in a few sites that were seasonally dry; and fire loads were vastly reduced, almost wholly anthropogenic. The environment resisted fire. Only constant attention by swidden agriculturalists and hunters, only on sites prepared by humans into slash or prairie, could fire persist. The island overflowed with cornucopic diversity—a continental flora in miniature; a fifth of known human languages. By contrast, Australian fires burned over long periods and large areas, anthropogenic and natural ignition complemented each other, and once installed fire became inexpungable.¹⁰

The greater the commitment to fire, however, the greater the difficulty of removing it. Pyrophilia had its perils. Fire could become a kind of biotic addiction, seemingly relieved only by more fire. It opened Old Australia to fire-hardy species and denied it to others. It imposed a special character on the bush, and committed it to a special vulnerability. Any change in the frequency, intensity, or timing of fire would ramify throughout the continent. Species that shaped Australian fire would be, in turn, shaped by it. If humans used fire to reorder the bush, it was equally true that the bush, through fire, would reorder human society. What it granted as power, fire also took away as weakness. Fire, for humans, meant both access and danger.

Those conditions that made fire so universally powerful also placed it beyond total human control. Bushfires could burn independently of any human will or act. If fire was a universal solvent, bushfire was also a brooding, ineffable, sometimes fatal presence that from time to time could burst forth with terrifying effect, a psychological as much as a physical presence, a nightmare out of a Gondwana Dreamtime.

When, with the dreams of Egremont, a strange

And momently approaching roar began

To mingle, and insinuate through them more

And more of its own import—till a Fire

Huge in imagination as the world

Was their sole theme: then, as arising wild,

His spirit fled before its visioned fear …

—CHARLES HARPUR, “The Bush Fire”