The Biggest Estate on Earth

by Bill Gammage

  Among their conclusions in 1991, they report ‘evidence which seems to point to a remarkably stable vegetation pattern over the past century’.42 They go back further, sometimes to the 1830s, more often to the 1870s–1890s, though both at best sketchily, including when criticising Eric Rolls’ book on the Pilliga, A Million Wild Acres. They say that Rolls ‘offers opinion’ on the effect of Aboriginal fire on the forest, and that they will ‘question the details’ of his ‘sequence of events’, the first of which is the pre-European state of the forest.43 They do not do this, resting instead on the baseline they set by excluding Aboriginal intervention—and early European intervention, because ‘there is little evidence of it’.44 This brings their baseline closer to the date of their first useful source, 1914. How can they claim to question Rolls’ details on the pre- and early post-European Pilliga when their earliest substantial evidence is dated 1914? They don’t say, and they don’t do it, yet they imply that objective data shows that Rolls is wrong. This sense permeates the paper.

  Norris et al write, ‘In the 1914 survey, the surveyor recognised areas of thick forest . . . While problems arise here with the exact meaning of a “thick forest”, these denser areas are not obvious on the air photographs of later years [1938 and 1970]; a reversal of the expected trend if the forest was becoming denser.’45 Thick forest was there in 1914: a scientist saw it. If Norris et al could not see it in the photos, they might more sensibly, though not objectively, assume that the thick forest has thinned. Yet they state that humans rarely impacted on the forest core between 1914 and 1938.46 How do they know? Did the forest self-thin? And how does this demonstrate a ‘remarkably stable vegetation pattern over the past century’?

  The authors then state that dense pine patches in the Pilliga core are evident in three twentieth century records, and take issue with ‘the general belief that . . . dense shrub cover was virtually unknown at the time of first settlement’.47 Who had that belief in 1991? Not Rolls. Not any historian or scientist I know of. Aboriginal mosaic burning, including leaving dense scrub, was quite widely accepted by 1991. The authors cite no source to support their claim. Their earliest detailed source is 1914: they seem to think that the 1914 forest is a guide to its condition 80 years before. Perhaps it is as an ‘impression’, but not in the precise way the authors use. For example they report 1914 mosaics (‘areas’48): were these survivors of 1788 fire, or favourable regeneration areas, or both, or something else? We don’t know. We don’t know where the 1914 mosaics were. A better method is to seek this evidence for about 1914 and about the 1830s, and if that fails try a different study area, or try other questions: how did those dense patches get there? If trees were dense there, why not elsewhere?

  Scientists (and historians) thirsting to milk the historical record often shackle themselves in this way, confining their sources to a limited study area. This deprives them of sources and context, tempting them to ask and assume more than the sources they do find can sensibly say. Of course all evidence should be probed for what it might say, but that does not justify making it say what it doesn’t, or making it say of one time or place what it actually says of another. A better approach is to seek as well sources and context beyond the study area. Context is vital. You must get inside a source’s head, steadily building a subjective impression not of what you think was meant, but what he or she thought was meant.

  Rod Fensham compares Leichhardt’s maps and descriptions of inland Queensland with 1945–78 aerial photographs of the same country.49 With such work, Fensham says, the ‘challenge is to develop more rigorous and explicit ways of interpreting [historical] information’.50 Like Norris et al he is interested in vegetation thickening, and he too concludes that his comparison ‘does not support the hypothesis that vegetation thickening has been extensive or substantial. On the contrary the study suggests that the structure of the vegetation has been relatively stable.’51

  To establish his baseline—Leichhardt’s route—Fensham cites Glen McLaren’s Beyond Leichhardt to claim that Leichhardt’s ‘navigation records have proved highly accurate’.52 McLaren says no such thing, instead writing that Leichhardt’s latitudes average 2 kilometres south and his longitudes 34 kilometres east or west of his actual location, and that within three months the loss of his compass rendered his bearings ‘frequently somewhat inaccurate’.53 McLaren could trace Leichhardt’s route with ‘considerable accuracy’ as far as the Mitchell River, that is for about 70 per cent of the country Fensham discusses, but of 309 Leichhardt campsites he could locate only 79 exactly, 35 within about 400 metres, 93 within 400–800 metres, and therefore 102—a third—not at all.54 Whether this is enough to compare vegetation then and now along Leichhardt’s route is difficult to say. My guess is sometimes yes, sometimes no. Fensham always says yes. A good historian would be cautious of investing so much in so little, instead keeping to when vegetation happens to be described near one of those 79 proven campsites—of course assuming McLaren’s ‘impressions’ as a historian are acceptable.

  Fensham assumes that Leichhardt uses words consistently to describe country, influenced neither by changing landscapes nor by adjusting usages as he understands the land better. Fensham writes, ‘It is clear from Leichhardt’s journals and letters that terms describing the structural character of vegetation have specific meaning.’55 It is not clear. Fensham often quotes Leichhardt qualifying key words for country.56 No doubt the words are broadly consistent: rainforest could never be called open. But this does not make them ‘rigorous and explicit’ enough to compare them usefully with 1945–78 aerial photographs across a stretch of inland Queensland.

  To tabulate Leichhardt’s words, Fensham constricts them. He quotes Governor King’s 1805 definition of scrub—‘shrubs of low growth’—which he says is ‘consistent with Leichhardt’.57 Yet he quotes Leichhardt’s men riding horses through ‘scrubs’ overtopping them.58 What then does ‘low’ mean? He offers another definition: scrub ‘includes a very broad range of tall stratum and low stratum structural categories’.59 Is this ‘rigorous and explicit’? Do we know if Leichhardt ever used ‘scrub’ in this sense, let alone consistently? In 1832 his contemporary Mitchell stated, ‘“bush” or “scrub” consists of trees and saplings, where little grass is to be found’,60 while in 1834 Breton wrote, ‘“Open forest” is that description where there is no underwood, and the trees in general are far asunder. “Scrub” is dense forest with much underwood and bad soil.’61 Fensham compounds the problem by stating that ‘brush’ is ‘virtually synonymous’ with scrub.62 It might be now, it wasn’t then. Breton noted,

  ‘Vine brush’ is almost impenetrable forest, where great numbers of climbers, parasitical plants and underwood, are found: the soil is generally good. ‘Brush’ is forest with occasional underwood, but not so dense as ‘scrub’: besides which, the latter may be without large trees: ‘brush’ is never destitute of such.63

  ‘Brush’ often meant what we call rainforest. Sometimes Leichhardt seems to use it in that sense (‘vines’), sometimes not (‘low bushes’). How to be rigorous or consistent about that?

  From scrub to dense forest. Fensham claims that Leichhardt ‘does not refer to “dense forest”’,64 yet quotes Leichhardt’s ‘very dense scrubby Ironbark forest’.65 What did Leichhardt mean? A dense forest can be spaced trees with dense understorey, or close trees with or without understorey, or each in patches, and in time one might or might not become another. To argue for Fensham’s ‘relatively stable’ vegetation structure66 you need to know which was which in Leichhardt’s time. Fensham merely subsumes one alternative under Leichhardt’s word ‘thicket’: ‘The term thicket seems [sic] to be applied to forest with dense patches of young trees of species represented as tall stratum dominants.’67 I suggest that a ‘thicket’ is confined in area, with an under-storey and canopy sometimes of different species. Leichhardt thought so too: he refers to ‘Melaleuca and grass (?) thickets’.68 I can’t link this to Fensham’s definition. Neither can he: except for
cypress pine he later excludes references to ‘thicket’ as ambiguous.69 Since his central purpose is to test whether vegetation has thickened, excluding thickening’s most likely source is venturesome.

  In Leichhardt’s time people called ‘forest’ what we might call woodland, or even grassland. The Australian National Dictionary offers: ‘Forest Obs[olete] A tract of open, well-grassed land, with occasional trees or stands of trees.’ It quotes first King in 1805: ‘Forest land—is such as abounds with Grass and is the only Ground which is fit to graze; according to the local distinction, the Grass is the discriminating character and not the Trees, for by making use of the Former it is clearly understood as different from Brush or Scrub’, and second the American Charles Wilkes in 1844: ‘“forests” . . . are very different from what we understand by the term, and consist of gum trees . . . so widely scattered that a carriage may be driven rapidly through them without meeting any obstruction’.70 How did those forests become so? Why aren’t they still so, if ‘stable’, as Fensham claims?

  ‘The term “plain”’, Fensham states, ‘clearly implies flat country that is either treeless or very thinly timbered.’71 This is not clear. It nearly matches Mitchell in 1831: ‘almost all land free from trees’,72 but not Peter Cunningham in 1828:

  Plain is a term of varied meaning throughout the colony, being generally however applied only to spots of land destitute of trees, without reference to the evenness of the surface; a patch of a few acres receiving this appellation equally with an area of many thousands73

  or David Waugh in 1834: ‘by plains in this country is meant not level ground, but ground either wholly or partially clear of timber—they may be real flats, and indeed generally are, but not necessarily so’.74 In any case Fensham soon confronts Leichhardt’s ‘scrub plains’, which he says ‘include patches of scrub within an otherwise treeless area’.75 These might or might not be today’s ‘patchy plains’,76 but either way, how does Fensham know? A little historical context should have convinced him that people then used the same word in different ways, just as they do now.77

  This treatment of Leichhardt’s language, making it ‘rigorous and explicit’ because Fensham needs it so, is alarming. Fensham says Leichhardt’s usage is consistent; Leichhardt’s text shows it is not. Even had it been, it does not follow that Fensham categorises it accurately or usefully, for he makes unproven assumptions about where Leichhardt was, and what he is saying. In part Fensham recognises these and other imprecisions,78 but they do not deter him. He points out that he is ‘specifically addressing the hypothesis that vegetation thickening has been substantial and extensive over more than 100 years of pastoral management’.79 ‘Substantial’ has been claimed. Has ‘extensive’, in pastoral areas? Fensham’s conclusions do focus on forest, but include ‘open forest’ defined as 5–55 per cent crown cover.80 Mitchell defined ‘forest’ as ‘an open wood, with grass’.81 How to get 5–55 per cent from that?

  Fensham assumes that early reports can be used as baselines for tracking changes in vegetation density over time. I agree, and as he states he and others have elsewhere found evidence of vegetation thickening since 1788.82 The changes can be extensive and obvious, suggesting that they began when Aboriginal management ceased: certainly, apart from random fire, no-one has yet proposed an alternative. But changes in time should not be pushed too far. Imprecision in the sources, even by someone as observant as Leichhardt, warns against that. What he and others better tell us is of changes in place. Fensham quotes Leichhardt on one type of vegetation giving way to another: forest to plain, grass to tree belts or clumps, and so on.83 Where they can be found, such locations are worth checking. They puzzled Leichhardt. Fensham quotes him observing, ‘It is a singular character of this remarkable country, that extremes so often meet; the most miserable scrub, with the open plain and fine forest land.’84 Singular indeed. Why? Leichhardt could see that they did not correlate with soil, salt, altitude or aspect. Instead they point to controlled and repeated burning in 1788. When Fensham suggests reduced fire ‘frequency and intensity’ in European times,85 isn’t the most puzzling conclusion that the vegetation has remained stable? He suggests that rain and drought regulate woody vegetation fluctuations around a rough equilibrium.86 How rough, and why over his 100-year span? In short, Fensham employs assumptions about historical sources fully accredited within his discipline, and gets into a tangle as a result.87

  In 1997 JS Benson and PA Redpath ‘re-examined’ DG Ryan et al’s 1995 booklet on early landscapes, and questioned landscape ‘hypotheses’ by Rolls (1981) and Flannery (1994).88 They examined three main themes: fire frequency, how much forest was dense and/or with a dense understorey, and how much regrowth occurred because Aborigines ceased burning. On the first, they show that Ryan et al exaggerate in claiming general fires every year or so. The second becomes a quibble on words: if it has substance Benson and Redpath don’t show it. On the third they and Ryan et al are both right, depending on how long after 1788 fire ceased their various examples are. Their criticism of Flannery is largely on matters relating to deep time, and of Rolls is ineffectual and based on ‘evidence’ of the Fensham variety. For example they criticise Rolls’ estimate based on historical sources of 3–4 large trees per hectare in the Pilliga. They think 30 more likely.89 They don’t say why.

  They begin by noting the presence of history and the absence of science in Ryan et al: ‘Ryan et al present one line of evidence in trying to explain pre-European vegetation and overlook the extensive scientific literature on past and present vegetation, and on fire ecology in Australia. By referring to the scientific literature, and by re-examining the same historical sources’ they propose to challenge Ryan et al, Rolls, and Flannery.90

  In fact, where scientific research exists they simply assert its paramountcy. Where science and history clash, they say, science must be right. This leads them to claim, on no scientific basis, that Cook’s ‘lawns’ (ch 1) were heath, seen from out to sea.91 Cook lived by one of his lawns, Grassy Hill at Cooktown, for seven weeks, and climbed it several times (picture 13). The claim is not objective, and wrong. Similarly, Benson and Redpath merely speculate on alternatives to Ryan et al’s sources, and sometimes show little skill in interpreting historical evidence.92 They write, ‘Vegetation types such as rainforest, wet sclerophyll eucalypt forest, alpine shrublands and herbfields, and inland chenopod shrublands, along with a range of plant and animal species, would now be rarer or extinct if they had been burnt every few years.’93 Some of these types were rarer in 1788; in any case no-one suggests that people burnt all Australia with the same fires at the same intervals. Yet Benson and Redpath conclude that climate is ‘the main determinant in vegetation change’.94

  Benson and Redpath concede some regrowth after 1788, but claim that clearing outweighed it.95 Others argue this,96 but it is a non-sequitur, and doubtful anyway, especially for hills. Early squatters did not graze hills: they had better grass on flats, so hills thickened. The people who called Black Mountain in Canberra heavily timbered in the 1860s and the 1960s were describing the same burnt woodland Hoddle saw in 1832 (ch 9). More to the point, why did Benson and Redpath’s regrowth occur? Why wasn’t the vegetation as dense in 1788? The clearing baseline Benson and Redpath use was well after 1788 fire was stopped, so too late. In general only accounts within say 20–40 years of the end of 1788 fire suffice, depending on the country. Later than this, and trees and scrub have got away.

  Benson and Redpath use definitions for closed vs open forest and woodland vs open woodland set down by scientists in 1990,97 echoing assumptions Fensham and others use. This is useless in assessing historical sources, which had no obligation to be consistent even within themselves, let alone across future centuries. People differ, and over years or even days might change thinking, or use the same word to include the very landscapes later researchers are trying to distinguish. Few if any state measurably what they mean, none I know uses defining words consistently, and no definition of vegetation from an
y single historical source can be converted into a general description of landscape, let alone used as an objective baseline. Yet scientists readily attach meanings to defining words, sometimes even tabulating or quantifying them as percentages, then using these to show some hypothesis or other. Here is a cutting edge between subjective history and objective science: history knows how circumscribed evidence is; science imagines that making a statement stark, or converting it to numbers or tables, makes it objective. This may save space, but gains no precision or clarity, rests on unproven assumptions, and generates venturesome conclusions. I puzzle why any discipline committed to objectivity troubles with attempting to force-fit sources.

  These attempts matter both on their own, and because others rely on them, with distracting results. George Seddon, a fine ecologist well aware of the impact of Aboriginal fire, quotes Alfred Howitt on Gippsland forest thickening after 1788 (ch 11). He has ‘no doubt’ that Howitt’s observations ‘are essentially correct’, but he finds Howitt’s explanation, that thickening was because 1788 fire ended, not ‘universally applicable’. He offers two proofs: that some forests were ‘dense and almost impenetrable at the time of settlement’, and, quoting a scientist, that it ‘seems that after a fire there is a natural succession from shrub understorey to an open parkland of mature trees and grass, but this takes some 40 years’ unless fire interrupts it. He therefore states that ‘Aborigines rarely burnt this country’, and quotes the scientist that a ‘natural succession is now reasserting itself within the Kosciusko National Park’.98