Perlin’s potentially perfect plants-and-people publication

A Forest Journey: The role of trees in the fate of civilization, by John Perlin, 2023. Patagonia Works.

When creating a reading list for my Plants and People module in 2002 one of the ‘finds’ I was most pleased with was the 1989 first edition of John Perlin’s A Forest Journey. It was a great book that told a fascinating plants and people story and was perfect for the course. Although my students should have been left in no doubt what I thought of that tome, I didn’t have the opportunity to share my enthusiasm for that book with a wider audience. But now I do with the publication of a new version of the book. So, what can I tell you about the 3^rd edition of John Perlin’s A forest journey [which book is here appraised]? In short, it’s a brilliant plants-and-people book(!). At somewhat greater length and in more depth…

What’s it about?*

In essence, the book’s idea is that human civilisations have been profoundly influenced and affected by the way people have used – and abused – trees and forest products. That notion provides the historical dimension to the book [and its sub-title The role of trees in the fate of civilization] in which the role of forests and timber in the rise and fall – or just rise in some cases – of many civilisation is analysed by Perlin. By considering many historical examples of the way humans have interacted with forest resources over millennia, and in view of the manner in which we continue to mismanage trees, Perlin concludes starkly: “To save our home and each other, we must actively protect what is left of the Earth’s forests” (p. 8). Sadly, as Perlin notes throughout the book, those lessons of history are still not being learned – even though some ancient commentators were well aware of the undesirable consequences of wide-spread forest clearance, and had written about it.

Perlin’s premise is developed and defended by detailed considerations of forest-fuelled both rises and demises of ancient civilisations particularly in the Middle East and around the Mediterranean – e.g. Bronze Age Crete, Classical Greece, and Ancient Rome – and of more recent entities such as the Republic of Venice. The empire-building ambitions of European powers are also considered, and documented in the case of Atlantic-sited colonies established by Portugal, initially in Madeira and then in the Caribbean and Brazil. Although the Portuguese civilisation has not fallen, Perlin makes a very strong case for the involvement of trees – e.g. to build ships and fuel its sugar industry – in its initial rise to power from the middle of the last millennium.

Two other societies that have also not yet fallen and disappeared are the subjects of the two biggest of the book’s 13 chapters. Interestingly, although that devoted to England only begins in 1485 CE, Perlin not only reminds us of much-older wood-consuming, iron smelting activities during the Roman occupation of that land, but also of the subsequent regeneration of the forests post-occupation. And it’s that resurgence of woodland that fuelled much of England’s (which later became Great Britain) growth, development and colonialist expansion. The chapter on America is such an amazing catalogue of timber-related usage that it is clear to see why that country could justifiably be considered a nation built on wood. To some extent, those two chapters can be viewed as separate and distinct sections. But, and importantly, Perlin points out the crucial and strategic wood-related connection between America (before it became the USA) and Britain [clue: mast ships], and is a reminder of a timber dimension to the interconnectedness and interdependence of societies.

But, since the fall of the ancient civilisations considered by Perlin, fossil resources such as coal, oil, and natural gas have been developed and exploited as energy sources. Whilst these have to a large extent replaced society’s dependency upon timber for fuel, this calorific substitution has not future-proofed modern-day civilisation against its own folly. Rather, global warming from CO₂ (e.g. Sarah Fecht) released from combustion of those fossil sources, and the climate emergency has given us different concerns that could determine whether civilisation as we know it survives, or declines and falls. And these modern-day preoccupations arguably still have a tree dimension in that it’s the switch from timber to fossil fuels that is having its own impact on the planet and people.

Furthermore, trees have always been about much more than fuel-wood. Ever since they evolved on Earth they’ve been changing the environment and continue to provide crucial environmental services, including promotion of human health and well-being (e.g. Jennifer Salmond et al. (Environ Health 15 (Suppl 1): S36, 2016; https://doi.org/10.1186/s12940-016-0103-6); Jessica Turner-Skoff & Nicole Cavender (Plants People Planet 1: 323-335, 2019; https://doi.org/10.1002/ppp3.39)).

So, and despite what we may choose to believe, humanity continues to be dependent upon trees and forest resources in one form or another: Trees continue to play a major role in the fate of civilisation. However, that life-sustaining power of trees is under constant threat; we still consume forests at an alarming rate for many purposes (e.g. removing trees to plant crops of soybean or pasture grass for beef production in the Amazon (Hannah Ritchie & Max Roser), and the global area covered by such wooded land continues to decrease (Hannah Ritchie & Max Roser). This deforestation is acknowledged by Perlin, and the take-home message from A forest journey is that poor forest stewardship seems to be the common denominator – the lowest common factor – that unites all human civilisations. Which is a damning indictment of, and a poor legacy for, humanity. But, Perlin still has hope that this situation can be changed – if we act with the necessary urgency.

Along our own forest journey we learn: about the relationship between deforestation and soil erosion [which can lead to silting of waterways and harbours, and development of mosquito breeding grounds in swamps], salinisation of soil [and consequent depressed agricultural yields which can topple civilisations], and droughts; the implementation of wood-saving – and forest-protection – measures of ancient societies; why mighty Venice wasn’t able to compete with other European powers in establishing colonies in the New World; the suggestion that collapse of Minoan civilisation wasn’t due to eruption of a Theran volcano (e.g. John Antonopoulos, Nat Hazards 5: 153–168, 1992; https://doi.org/10.1007/BF00127003) but increasing scarcity of timber; and that the UK’s Forest of Dean is regarded as the ‘nursery of the English navy’ (p. 283).

The book’s scope is considerable, stretching back 5,000 years with the cautionary tale of Gilgamesh and ‘ill-advised forest management’ in Mesopotamia (Joshua Mark), right up to the present day with a connection between forest loss and the Covid-19 pandemic. A further indication of the range of topics dealt with in the book comes from a glance at the Index, whose 11.5 pages of 3-columned entries go from ‘Abd al-Malik ibn Marwān to Zygouries, via: American colonies; axes; baths, Roman; bricks; carpentry; charcoal; deforestation; dowry, wood as; ecological consciousness; erosion; famine; fuelwood; glass industry; global warming; Hammurabi; house building; Iron Age; irrigation; Jefferson, Thomas; Kingston-upon-Thames; Knossos’ laws, wood use; log rolling bee; Maine (colony); Mesopotamia; Native Americans; New England; oak wood; old-growth forests; Parliament, English; pine wood; railroads; Rome; salinization; “ships of the line”; silver fir; transportation; United States; Uruk; Venice; Virginia (colony); wagonways; wheat; Xenophon; and Zeno.

It’s a great idea, but is it supported by evidence?

Yes! For all of the examples assembled by Perlin to support his thesis, he provides extensive references. These sources – indicated in-text by super-scripted numbers – amount to almost 1800 endnotes and are a combination of historical documents and up-to-date scientific articles. Helpfully, all of the sources have been published on-line, which reduces the book’s length quite considerably. In removing them from the book, Perlin has made the sources freely available to all so they can be scrutinised by interested and/or sceptical readers. They can be accessed here, or from this link, as “endnotes to A Forest Journey”. However, and as extensive as the endnotes collection is, a few more sources are needed in-text for some of the statements made – e.g. 1^st, 2^nd, and 4^th paragraphs on p. 14, re text in 2^nd half of 3^rd paragraph on p. 166, regarding resources made available upon dissolution of the monasteries on p. 235, and re 4^th paragraph of p. 444. In some of those instances it may just be a case of reciting an already-stated source to indicate that it also applies to the new paragraph.

Supported by such a wealth of endnotes, A Forest Journey appears to be one of the most thoroughly-researched, evidence-based, statement-sourced and -supported books I’ve read. Perlin has therefore set the bar extremely high for all plants-and-people books. Indeed, he’s done so for all fact-based publications. And for that we should thank him [although, I suspect, many lesser authors happy to produce poorly- – or even un- – sourced publications will be rather less appreciative…]. However, although the veritable torrent of evidence-based statements in A Forest Journey seems irresistible, I must add a note of caution about accuracy and appropriateness of the sources cited [see ***].

It may be evidence-based, but is it credible?

Arguably, to answer that question you’d need to be an expert in the history of all the civilisations considered in the book, and in disciplines such as technology, ecology, forest management, economics, etc. However, because Perlin has assembled an extremely diverse range of sources – from historians, technologists, etc., and has sought advice and criticism on chapters from scholars with the necessary expertise (Acknowledgements p. 509) – one can reasonably conclude that that hard work has been done for us. As a botanical generalist with an appreciation of plants and people interactions, I am persuaded that Perlin’s interpretation is entirely plausible.

However, whilst wood is probably unlikely to have been the only factor that has influenced the fate of civilizations over millennia (e.g. Jenna Frawley re decline of the Minoan civilisation), Perlin paints a compelling argument of the relevance and importance of trees and forest resources to humanity and therefore their likely contribution to the rise and fall of societies. And that theme is not just relevant to civilisations that are long gone such as the Ancient Greeks and Minoans, it is also applicable to the changing fortunes of more modern-day societies. This notion is especially well-developed in Perlin’s detailed consideration of the early days and rise of the USA [whose ‘story’ commences in 1673 CE].

A Forest Journey is an excellent example of how to marshal evidence in support of an hypothesis. But, the book is more than a doom-and-gloom laden catalogue of ‘failed’ – or flawed – societies. In focussing on the relationship between trees and people, Perlin sounds a note of caution that is all-too relevant to humanity in the modern day. And that is brought home – and as up-to-date as it can be – in the final chapter where he mentions the connection between forest loss, bats, and coronaviruses.

What’s new to this edition?

When I read the first edition of A Forest Journey, I was very impressed and didn’t think it could be improved. Fortunately, the author thought differently: “Since A Forest Journey was first published in 1989, I have continued discovering new material that would add breadth and relevance to the book, believing that one day a new edition would appear. The new edition not only emphasizes the importance of forests for the wood they have supplied for the development of societies from ancient Mesopotamia to nineteenth-century America, but also shows the role forests have played in making large-scale terrestrial life—including us—on planet Earth possible” (p. 13). Although most of the first edition’s original text is retained, it has been supplemented with additional sources, and much new material has been added.

In particular, two important additions in the present edition are the sections about China and India, and Africa, and the consideration of Archaeopteris [https://en.wikipedia.org/wiki/Archaeopteris], ‘the earliest known modern tree’ (Brigitte Meyer-Berthaud et al., Nature 398: 700–701, 1999; https://doi.org/10.1038/19516) in the first chapter. Inclusion of China and India – both of which have forest-based ‘founding stories’ – considerably extends the geographical range and civilisations encompassed by the book. New mention of Africa also expands the global coverage of Perlin’s hypothesis, and documents that continent’s ancient and highly-sophisticated knowledge of steel producing technology**, whose level of accomplishment was not replicated by Europeans for almost 2000 years. The introduction of Archaeopteris adds an important temporal extension to the story – back almost 400 million years – with an account of the global importance of trees since they first evolved.

A third important addition is the Epilogue which considers the relevance of forests for humanity’s survival [as if the preceding 480 pages hadn’t already convinced the reader of this(!)]. This includes important discussion about the relative merits of old-growth forest versus younger, intensively-managed forests, and the ecosystem services that trees provide. In respect of the latter, Perlin considers such contributions as their role in carbon storage [including the combined role of roots and mycelia in locking-up CO₂ in the soil] and climate change, temperature control [with the eye-popping revelation that “without the forest canopy, seasonable temperatures in the Amazon basin could get up to 41 degrees warmer” (p. 496)*** ] and water supply, biodiversity, and human health. Although there’s no specific mention of the practice of forest bathing in connection with human wellbeing, Perlin mentions the role of forest loss in the spread of diseases such as lyme disease, and malaria in Brazil. But, probably the most jaw-dropping moment of the whole book was mention of bats and the Covid-19 pandemic with reference to Aneta Afelt et al’s prescient article entitled ‘Bats, Coronaviruses, and Deforestation: Toward the Emergence of Novel Infectious Diseases? (Front Microbiol. 2018; 9: 702; doi: 10.3389/fmicb.2018.00702)(!).

Another welcome addition is the book’s 2-page map on pages 20-21. However, although entitled ‘world civilizations’ this graphic mainly places in time and space the major Mediterranean, and Mesopotamian empires that are discussed at length in the book. Whilst that is useful in helping the reader get the timings and relationships between these various societies sorted out, it certainly doesn’t cover the whole world – the Americas are clearly absent. Its title could therefore do with some amending. Furthermore, and noticeably many ‘home-grown’ civilisations are overlooked in place of occupying forces such as the British Empire in large parts of Africa, Arabia, and the Indian sub-continent, and the Roman and Muslim empires in place of many indigenous societies along the north African coast and into Arabia and the Middle East. And it’s the areal extent of African iron works that is indicated rather than names of any of the peoples involved. But, this is not a complete history of the peoples of those regions, and is only intended to serve a much more-limited purpose.

Inclusion of on-line resources are new and comprise: a ‘synopsis of A Forest Journey’ [masterful summaries of each of the book’s chapters]; the ‘Endnotes’ [all of the 1780 sources enumerated in-text]; and ‘Deforestation and Reforestation maps from ESRI [Environmental Systems Research Institute, Inc]’. This latter resource actually contains far more than is suggested by its description: In particular it includes an animated graphic showing sites of major cities from 3700 BC to 2000 AD. The teacher’s and reader’s guides for the book are yet to appear [as I pen this piece in late May 2023]. Where available on-line resources can be accessed here. There’s a wealth of information in those extra resources that add several layers of depth to the book, and represent considerable added-value.

Interestingly, although the book’s title remains the same, there’s been a subtle change to its sub-title, from 1989’s The role of wood in the development of civilization to this edition’s The role of trees in the fate of civilization. Not only does that emphasise that it’s trees more generally rather than wood specifically that’s concerned, but it also provides more of a predictive dimension to that people-plants interaction. We have been warned.

This edition appears so comprehensive that one wonders whether a future – revised/enlarged – edition can be contemplated. But, if it can, it can surely only enhance the solid foundation that has already been laid down.

Personal appreciation

Since reading the first edition of Perlin’s book I’ve been a fan. Reading this new version has only enhanced my appreciation of what he has achieved. Although A Forest Journey is undoubtedly a scholarly text [but, and despite being a plant-based story, Perlin has avoided use of scientific names except for Archaeopteris, and Burkea africana], it is also highly-readable. Its readability is helped by the numerous illustrations [mainly in black-and-white for historical material, but colour photographs of modern day sites and vistas] that break up the text, and by having lots of quite short sections of text with instructive headings. This combination of erudition and engaging style is always nice to see.

It’s also a very informative book. I learnt a lot about people from Perlin, and a considerable amount of history, especially of the Mediterranean and Middle East, but also America and England. I also now have a much better appreciation of the role played by forests and the ways in which humans have – and continue to – use, exploit, and abuse trees and tree products. Whilst it can be a little overwhelming with all of its dates and different civilisations, the new-to-this-edition map greatly helps in trying to get one’s head around who was doing what, where, when, why, to whom – and how.

Summary

This edition of A Forest Journey by John Perlin is even better than the 1989 version. It continues to be a great story that’s very well told, but with much additional material and resources. Although this version isn’t perfect, it’s not far off, and shows what a model plants-and-people publication can look like. If you haven’t read the first edition, you’re in for a treat in this one. If you have read the first edition, this version is even better – and well worth the rereading. A Forest Journey is a brilliant book that should be compulsory reading for everybody – not just those with an interest in plants and people.

PS, if you don’t want to commit to the full book yet, the masterful summaries of chapters and sub-chapters are freely-accessible here, or from the book’s main site here, as “a synopsis of A Forest Journey”.

* It’s about time this wonderful book was better known, more-widely read, and its conclusions and suggestions heeded, and acted upon. And we apparently have to thank Yvon (David Gelies) and Malinda Chouinard of Patagonia Inc. [which business they no longer own (Andrew Weaver)] for this revised edition seeing the light of day [from Author’s Foreword on p. 7]. So, a big shout-out to that enterprising duo!

** In case you were wondering how steel and trees are linked [and it’s not by way of the taxonomically-diverse group of trees known as ‘ironwoods’], it’s via charcoal – the product of high temperature treatment of wood in a low-oxygen environment. As a fuel, charcoal is used in preference to wood to generate the sufficiently-high temperatures required in the manufacture of steel – and extraction of other metals, such as copper, from its ore. The importance of tree-derived charcoal to metallurgy (Paul Shewmon et al.] is so fundamental to human development that there is a suggestion that the Bronze Age and Iron Age should really be called the Charcoal Age [as indeed they are in the timeline to Perlin’s world civilizations map, beginning in 4000 BCE]. And, for good measure, “The Stone Age should more accurately be called the Wood Age, because most of the tools used by ancient hunter-gatherers were made of wood” (p. 31), citing Yuval Noah Harari in his book Sapiens: A brief history of human kind. On which basis, trees and wood are even more important to human history than we have been used to acknowledging.

*** Irrespective of whether the degrees were Fahrenheit or Centigrade, and although a source was cited, I was sceptical of the claim. I therefore checked Perlin’s source – C. Kevin Boyce et al’s Angiosperms Helped Put Rain in the Rainforest: The Impact of Plant Physiological Evolution of Tropical Biodiversity (Annals of the Missouri Botanical Garden 97: 527-540, 2010; https://doi.org/10.3417/2009143). Reading page 533 of the article that Perlin cited specifically for this fact, the only mention of temperature differential was in this text: “Because evaporation entails the transfer of large amounts of energy from sensible to latent heat (Lee et al., 2005), angiosperm transpiration also exerts a strong cooling effect with temperatures seasonally up to 5^oC warmer in their absence”, at the top of that page. Nowhere in the paper could I find mention of the 41 degrees difference stated by Perlin. So, although the notion that tree cover helps to reduce surface temperatures seems intact, it’s the magnitude of that effect that’s in question: Where does Perlin get his value from? And, how does that affect the accuracy of the other sources cited in A Forest Journey? It’s a matter of some concern that the only source I checked – out of the hundreds cited – appears to be wrong…