Can the environmental and wildlife conservation movements learn from the (distant) past? This turns out to be a fraught question, with many practitioners preferring to preach pragmatism over nostalgia. Journalist and writer Sophie Yeo agrees that there is no turning back time, but this is no reason to ignore history. In Nature’s Ghosts, she mixes several parts reportage with one part nature writing to both criticize different conservation approaches and showcase some really interesting research. Though centred on the UK, she also discusses projects and problems in Europe and the USA, and the book was deservedly shortlisted for the 2024 Wainwright Prize for Writing on Global Conservation^[1].

Nature’s Ghosts: The World We Lost and How to Bring It Back, written by Sophie Yeo, published by HarperNorth (a HarperCollins imprint) in May 2024 (hardback, 327 pages)

What unites Yeo’s criticism of current conservation practices is how they ignore the past. For example, the British approach of designating areas with particularly valuable habitat, flora, or fauna as sites of special scientific interest (SSSIs) aims to keep these frozen in time. Yeo counters that by resisting the natural dynamism of ecosystems, “these sites, like Peter Pan, may never grow up” (p. 64). EU subsidies as part of the Common Agricultural Policy aimed at enhancing biodiversity in practice have had the opposite effect, as discussed for Romania. They are disbursed on the condition that farmers abandon traditional practices, even though these are far more interwoven with the natural world than the centralised rules imposed by the EU. Fortress conservation, the designation of areas as nature preserves or national parks, has been frequently combined with the forced eviction of Indigenous people from their lands. A recent searing critique exposed its colonialist roots as it pertains especially (though not exclusively) to Africa. It replaces the actual past with a mythical past of virgin wilderness that never existed in the first place. Yeo adds that: “conservation should have never become about displacing people from the land. The wilderness is not a blank slate: until recently, it was our home, our larder, our library” (p. 150).

Yeo is more positive about the track record of rewilding though here the problem of baselines crops up. “The natural world has never experienced one perfect moment of Eden: it has always been a series of novel ecosystems” (p. 66). With nature forever in flux, where do you plant your yardstick? She is critical of the feted Knepp Estate: “whether the land amounts to a genuine approximation of wilderness or a glorified farm remains hotly debated” (pp. 54-55). She feels conflicted by the Carrifran Wildwood project in Scotland that has accelerated its rewilding goals by gathering tree seeds from all over Scotland and Northern England. She likes what she sees but also considers it an example of intense micromanagement: “In many ways, it couldn’t have been a grander monument to human intervention” (p. 72). The Finnish Snowchange Project has the more nuanced aim of integrating humans into the landscape, in this case by supporting traditional small-scale ice fishing. Project leader Tero Mustonen argues that rewilding becomes powerful once you integrate cultural knowledge into it.

Of course, Yeo acknowledges more than once, we cannot turn back time. There are good practical and philosophical reasons for conservationists to be pragmatic and future-oriented. However, “that does not mean that we should treat the past as irrelevant” (p. 5). So, how is the past relevant to conservation today? The second half of Nature’s Ghosts features fascinating research of which I can only discuss a few examples.

“Yeo is more positive about […] rewilding though here the problem of baselines crops up. “The natural world has never experienced one perfect moment of Eden: it has always been a series of novel ecosystems” (p. 66).”

First, the extinction of Pleistocene megafauna. To me, it has become uncontroversial middle ground in this ongoing debate to implicate both climate change and humans. Novel is the notion that humans effectively replaced megafauna as a keystone species, with a new suite of plants and animals becoming dependent on our role in ecosystems (think of the archaeological evidence for forest gardens). The displacement of traditional societies through colonialism has disrupted such relationships, such that rewilding should “reinstate not only the lost ecological functions of megafauna but also people” (p. 136). This is what Mustonen’s Snowchange Project aims for.

Second, shifting baseline syndrome. Originally developed by Daniel Pauly in the context of fisheries, this has become another staple when talking about lessons from the past. Novel is the idea that, with each passing generation, we have not just collectively forgotten how abundant the natural world was, but also how animals used to behave. Ecologists mistakenly assume that an animal’s current habitat is both its preferred habitat and the limits of its tolerance, with conservation boiling down to “wherever an animal lives now, we need more of that habitat”. One example given here is the wild bison in Poland’s Bialowieza Forest. These are not a relic species but refugees: “survivors that have been backed into a corner, making do with what little remains” (p. 170). Indeed, one South African ecologist studying them was puzzled as to “why these European people have cows in the forest” (p. 174). The fact that many plants and animals are more tolerant than we give them credit for is a feeble ray of hope in the ongoing maelstrom of extinction.

Third is how time matters both more and less than we think. On the one hand is the long shadow cast by past human activities. The advent of remote sensing technology in archaeology has e.g. revealed how presumed old-growth forest in France hides the ruins of Roman farms. Amazingly, the soil and plant communities still differ as a result of fertilizer application two millennia ago. One shudders to think what that means for the future legacy of today’s environmental footprint. Will future fossils indeed be technofossils? On the other hand is temporal dispersal. Yeo discusses the many ponds, pools, and puddles that once dotted Britain’s landscape but were backfilled over time. When such ghost ponds are excavated again, their old bottoms contain spores, eggs, and seeds that remain viable centuries later. Many plants and invertebrates can rely on dormancy as a survival strategy to bridge time. Step aside deextinction! This “is scratching back the surface to reveal the real thing” (p. 230).

“we have not just collectively forgotten how abundant the natural world was, but also how animals used to behave.”

Nature’s Ghosts flows over with thought-provoking ideas and Yeo is quick to step in and prevent them from being misinterpreted or hijacked. No, the traditional agricultural practices in Romania or Wales are not blueprints for feeding the world. No, the Finnish Snowchange Project is not “arguing for the revival of a Stone Age lifestyle in North Karelia” (p. 138). No, discussing traditional foraging is “not advocating for the return of a pre-agrarian society” (p. 144), etc. She is well aware that conservation debates have been toxic at times. But it does beg the question, if these are not solutions, then what is?

I have two minor frustrations with Nature’s Ghosts. First, Yeo is reluctant to name the elephant in the room, even if she comes close. When discussing traditional farming methods, she remarks how “fossil fuels enabled us to exceed earth’s natural carrying capacity” (p. 104). When discussing biodiversity loss, she concludes that “so long as humans remain dominant, nature can never return to its primeval abundance” (p. 181) and that “wildlife cannot be restored to prehistoric levels without massive reductions in the human population: the earth will only support so much life” (p. 169). The dreaded O-word is studiously avoided, possibly for fear of getting tarred and feathered. Second, her solution. By no longer seeing landscapes as something sacred (for which she thanks Christianity) we paved the way for today’s relentless extraction. “The trouble is not that the old stories have faded. It is that no new magic has emerged to take their place” (p. 255). Rather than revitalising old beliefs or rituals whose meaning has been lost, she thinks we each need to rewild ourselves and find new symbolic connections with the natural world. If you are of the pragmatic bend that might sound a bit wishy-washy. To my surprise, I actually agree with her. Somewhat. I agree that we are not moved by facts but by stories, so, yes, we do need a new narrative. However, I am rather thinking along the lines of Eileen Crist’s call for an ecological civilization that does not see nature as a mere larder, or Carl Safina’s call to abandon the Platonic dualism that has allowed us to think of ourselves as apart from nature. Abandoning the currently dominant fairytale of endless economic growth will mean a wholesale revision of our socio-economic system, likely involving a period of degrowth towards a steady-state economy. Tall order? Absolutely. Do I expect Yeo to here write the book-length treatment that such big topics need? No, but acknowledging them would have been nice.

Those niggles notwithstanding, Nature’s Ghosts is intriguing, discussing some of the fascinating insights gleaned from studying the past. Yeo has read up on the literature and gone to great lengths to speak to researchers and conservationists first-hand. Given how she combines journalistic flair and evocative writing to explain the relevance of this research, it is easy to see why the Wainwright Prize jury was impressed.

1. ↑ For all my fellow non-UK readers, the Wainwright Prize is an annual UK literary prize that is named in honour of British author, illustrator, and hillwalker Alfred Wainwright (1907–1991). It was first awarded in 2014, split into two categories (UK nature writing and writing on global conservation) in 2020, and saw a third category for children’s books added in 2022. Various sponsors have affixed their names to the prize over the years, resulting most recently in the James Cropper Wainwright Prize.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Yeo’s Nature’s Ghosts

Other recommended books mentioned in this review:

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

Greenland’s name might be considered one of history’s great ironies, apparently part of a cunning plan to attract Viking settlers. The locals simply called it Kalaallit Nunaat or “land of the Kalaallit”, after their people. However, once upon a time, Greenland was green. Tropical Arctic is the fruit of an 18-year collaboration between two palaeobotanists and an artist to bring to life the plant fossils found in East Greenland. In three paintings, it provides a glimpse of Greenland during a 10-million-year window at the Triassic–Jurassic boundary, some 200 million years ago. Much more than a coffee table book, it details the research that goes into producing scientifically accurate artwork, making it a rare treat for readers interested in botany and palaeontology.

Tropical Arctic: Lost Plants, Future Climates, and the Discovery of Ancient Greenland, written by Jennifer C. McElwain and Ian J. Glasspool, illustrated by Marlene Hill Donnelly, published by the University of Chicago Press in February 2022 (hardback, 138 pages)

I will admit that when I first leafed through this book it was not quite what I was expecting. Spoiled as I have become by portfolios of palaeoart I thought this was going to be an art book first. Seeing just three full-page spreads (and, granted, plenty of accompanying sketches) I was mildly surprised. In that sense, Tropical Arctic is an object lesson in patience and the rewards that come with slowly drinking in the details.

To give some background, 200 million years ago Greenland was positioned at a latitude of roughly 50° N (think modern-day Dublin) instead of today’s 71° N and had a warm and muggy climate, not unlike today’s Florida. But things were about to get a lot warmer. The Triassic–Jurassic boundary was a time of upheaval and marks one of the five great mass extinctions. The supercontinent Pangaea split up and the Atlantic ocean was born. This process was accompanied by extensive volcanism for some 600,000 years that led to the formation of a large igneous province, the Central Atlantic Magmatic Province (CAMP). Atmospheric carbon dioxide concentrations shot up from 600 to an eye-watering 2500 parts per million, resulting in an average global temperature rise of 7°C.

Fast forward to 2002 when palaeobotanists Jennifer C. McElwain (co-author of the textbook The Evolution of Plants) and Ian J. Glasspool were part of a team excavating plant fossils in East Greenland. The first chapter recounts the excavation in photos and words, giving you a good feel of both the geological setting and the day-to-day reality of extracting fossils from a 70-metre cliff face under Arctic conditions. Equally interesting is the careful methodology of the excavation. Rather than just presence/absence data, the team was interested in measuring the abundance of different plant species in each of the fossil beds. How do you do that? And, given the vagaries of the fossil record, what caveats and assumptions underlie the results?

“The text […] provides a fascinating mix of palaeobotanical details and revealing insights into reconstructing extinct plants.”

With the fossil haul back in the lab, McElwain and Glasspool enlisted the help of Marlene Hill Donnelly, a scientific illustrator with the Field Museum in Chicago. She asked the fateful question: what colour were those leaves before they fossilized? The three chapters that follow detail the work that went into each of the three gorgeous and detailed paintings depicting a moment in time before, during, and after the mass extinction. The text thus provides a fascinating mix of palaeobotanical details and revealing insights into reconstructing extinct plants. Let me give you a few examples.

Many Triassic species left no living descendants, one example being Czekanowskia, a plant with ribbon-like leaves. Donnelly resorted to making models out of thin sheets of various materials on which she indented vein patterns to see how their leaves drooped down from the stems. Other groups persisted, such as ferns, cycads, and ginkgos. Flowering plants had yet to evolve, but insects were already around. Microscopic studies revealed egg-laying scars on Gingkoites leaves that are ascribed to streamside dragonflies, leading Donnelly to include several dragonflies in the final piece. Leaves of the vine Lepidopteris ottonis showed water pores at their tips, so Donnelly has depicted these leaves with sap exuding from them, so-called guttation droplets resulting from high internal fluid pressure.

One of the fossil beds captured the plant world in the throes of volcanism. Contemporary experiments have shown how exposure to increased sulfur dioxide concentrations, a gas released during volcanic eruptions, results in yellow patches (chlorosis) or dead leaf tissue (necrosis), a detail Donnelly included. Furthermore, leaves grew rounder in the experiment, a change also seen in Greenland’s fossil leaves. At the Triassic–Jurassic boundary, there is a spike in so-called disaster taxa: hardy plants such as ferns and horsetails. Both feature prominently in Donnelly’s second painting. Once we move into the Jurassic, certain plants, called Lazarus taxa for their seeming resurrection, return in the fossil record. Did they go locally extinct, migrate elsewhere, or were they around but temporarily not preserved as fossils? Other species decreased in abundance and the authors write that “The Jurassic ecosystems […] were certainly not restored mirror images of the Triassic forests” (p. 86). In several places, the authors draw parallels to our current era of anthropogenic global warming as the past can offer a baseline of what to expect. However, given that we are emitting greenhouse gases approximately 10–100 times faster, we should not be surprised if some changes will be exacerbated.

“A clever feature of Tropical Arctic is that each chapter features several close-ups of the final artwork to highlight some of the […] details in isolation.”

A clever feature of Tropical Arctic is that each chapter features several close-ups of the final artwork to highlight some of the above-mentioned details in isolation. Once you get to the two-page spreads showing the finished works, you do so with a better appreciation of all the details, rather than being overwhelmed and overlooking them. An appendix shows photos of some of the common or notable fossil leaves found in Greenland and features an interesting introduction to the species concept used by palaeobotanists. Given that most fossils are isolated plant parts and that you cannot observe breeding behaviour, you cannot rely on the biological species concept. Palaeobotanists instead use so-called form taxa based on morphology. This can result in the rather surreal situation where different parts of the same plant are categorised as very differently named genera and species.

As Mark Witton has also argued, careful restoration of plant life can greatly enhance the credibility of your artwork. Tropical Arctic takes this one step further. “Most dioramas and landscape reconstructions of the geological past focus on the enigmatic carnivore of the time, surrounding it with ambiguous vegetation that is difficult to pinpoint to a particular era. Our portal view of the Late Triassic forest floor turns this usual paradigm on its head: the vegetation is rendered in detail, and is of its time and place” (p. 44). For that reason alone, this is a rare treat, but the addition of a detailed look at the research and thinking behind resurrecting Greenland makes this a unique book.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Tropical Arctic

Other recommended books mentioned in this review:

__________________________________________________________________

We often think of tropical forests as pristine wilderness, untouched by human hands. In Jungle, archaeologist Patrick Roberts shows otherwise. A wealth of research reveals a long and entwined history that saw cities and agriculture flourish in this habitat, while later brutal colonial exploitation underlies many of today’s inequalities and environmental problems. Though revisionist and confrontational in tone, Jungle is a breath of fresh air by not falling for simple narratives. Instead, it retains a welcome dose of nuance and willingness to acknowledge complexity.

Jungle: How Tropical Forests Shaped the World – and Us, written by Patrick Roberts, published in Europe by Viking (a Penguin Books imprint) in June 2021 (hardback, 405 pages)

In 2019, Roberts published Tropical Forests in Prehistory, History, and Modernity with Oxford University Press. A rather expensive book that is dense and scholarly, I was nevertheless very impressed with it. Naturally, the first question is whether Jungle rehashes that book for a general audience. It does, but only to an extent. Next to being far more outspoken, Roberts has also decided to make this the complete and utter history of tropical forests by taking you all the way back to the beginning. Jungle thus ends up being a book of three parts.

First is a deep-time history that starts in the Cambrian with the arrival of the first land plants some 500 million years ago. Plants quickly became a planet-shaping force. Increased rock weathering drew down atmospheric CO₂, leading to an ice age marking the Ordovician–Silurian boundary, while Carboniferous forests in death ultimately became the coal reserves fuelling our Industrial Revolution. This part of the book also retreads dinosaur and mammal evolution by focusing on what is normally the vegetal backdrop to this story. There are many surprises in store when you take a plant perspective. For example, palaeontology has accustomed us to the idea of five mass extinctions, but, as one paper puts it plainly, the plant fossil record reflects just two great extinction events. And mammal evolution saw two radiations well before the dinosaurs went extinct, the first linked to Jurassic gymnosperm-dominated forests, the second to the encroachment of angiosperms in tropical forests during the Cretaceous.

Similar counterintuitive delights await you when Roberts turns to the story of human evolution, which was the starting point of his previous book. The idea that we evolved by venturing onto the savannah makes sense on the face of it, Roberts admits, but look harder and the role of forests becomes apparent. Bipedality may very well have evolved in the trees, as evidenced by the limbs of Ardipithecus ramidus. And savannahs are not just endless rolling grasslands but encompass a range of plant types, including trees and forest patches. Roberts also favours a pan-African model for the origins of Homo sapiens. We did not originate in one single place. Instead, “our ancestors lived in distinct, but interconnected, populations across Africa” (p. 102). And when it comes to our dispersal around the world, forests had their role to play, next to savannahs and coastal routes: “our species was not a one-trick pony and was, quite literally, everywhere by the close of the Pleistocene” (p. 114)”. Humans are nothing if not flexible generalists.

“archaeological evidence […] of plant cultivation in tropical forests […] “gives us a remarkable lens into some of the most ecologically savvy farmers there ever were“”

The second part of the book covers our prehistory. Here, Roberts surveys the lines of archaeological evidence that show the long history of plant cultivation in tropical forests and how they “give us a remarkable lens into some of the most ecologically savvy farmers there ever were” (p. 131). These farmers left the forests largely standing, even if species composition was modified. Similarly, island archaeology has revealed that, with some sensibility, humans have long coexisted with native fauna on small and supposedly fragile islands. Finally, thanks to modern remote sensing technology such as laser scanning, there is the spectacular revelation that the tropics were home to large cities and thriving civilizations. Rather than our blinkered view of what cities look like, archaeologists refer to them as agrarian-based, low-density urbanism, and Roberts suggests that they could be “an attractive model for present-day urban planners looking for ‘green cities’” (p. 170).

The third part of Jungle is the most outspoken and confrontational. Here, Roberts covers the era of colonial exploitation from the fifteenth century onwards, including the horrors of the demographic collapse following the Columbian exchange and the ensuing trans-Atlantic slave trade. He convincingly argues how these lay the groundwork for today’s economic and social inequalities. We enriched ourselves at the expense of tropical regions and today still take for granted many tropical products such as coffee, palm oil, and rubber. Simultaneously, we left behind impoverished regions that are now struggling in the face of climate change, deforestation, and soil erosion. These countries have become entangled in a global capitalist system in which their natural resources serve an insatiable export market rather than people at home. Roberts explicitly calls out that we all have our responsibility as consumers. When it comes to conservation, he particularly urges us to support and consult Indigenous people and be humble enough to acknowledge that Western science does not hold all the answers. Sometimes, Indigenous communities have the best local solutions based on intimate knowledge.

“What I particularly enjoyed is that Roberts retains nuance throughout and never shies away from complex realities […] history is frequently complicated and messy.”

Roberts is also critical of the concept of the Anthropocene. Our long history of impact on tropical forests can be used to argue for various starting points of this epoch, and, frankly, the name is inappropriate as it “is not a product of humanity as a whole, nor has it impacted all of humanity equally” (p. 249). I am sympathetic to the latter argument and agree that the former shows a gradual buildup of impact. Nevertheless, I find the concept of the Great Acceleration centred on the 1950s a convincing argument. To me, it represents a clear break with what came before in terms of speed and scale of our impact.

These are but some of the highlights of this information-dense book. What I particularly enjoyed is that Roberts retains nuance throughout and never shies away from complex realities. For example, despite the history of agriculture and cities in forests, disturbance and collapses did happen, though they were not always as dramatic and complete as we might envision them. Demographic collapse following the Columbian exchange was as much a consequence of microbes as of violence and forced relocations, as others have also argued. Simultaneously, Europeans tapped into existing networks of slave trade and interregional warfare, and some African tribes used it to further their own geopolitical ends. Though none of this should be interpreted as letting Europeans off the hook, it does show that history is frequently complicated and messy. One criticism is that Jungle is occasionally let down by somewhat convoluted writing. Especially in early chapters, there are a few sentences that run on for seven or eight lines with subclauses and bracketed sub-subclauses. Fortunately, the writing improves in later chapters. To complete that feedback sandwich I will praise the many illustrations, including some nice infographics designed just for this book.

Jungle is an immensely interesting book that offers a fine revisionist history of conventional narratives in archaeology and anthropology. A worthy follow-up to his 2019 book that expands on the material presented there, it offers much food for thought. If you have any interest in tropical forests I highly recommend you read this book.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Jungle

Other recommended books mentioned in this review:

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

The idea that trees communicate and exchange nutrients with each other via underground networks of fungi has captured the popular imagination, helped along by the incredibly catchy metaphor of a “wood-wide web”. Suzanne Simard, a Professor of Forest Ecology at the University of British Columbia, has developed this idea more than anyone else and happily talks of mother trees nurturing their offspring. This idea has not been without controversy in scientific circles, if only for its anthropomorphic language. I was both sceptical and curious about her ideas. High time, therefore, to give her scientific memoir Finding the Mother Tree a close reading.

Finding the Mother Tree: Uncovering the Wisdom and Intelligence of the Forest, written by Suzanne Simard, published in Europe by Allen Lane in May 2021 (hardback, 364 pages)

First, a quick biology lesson to get you up to speed. At the heart of this story are not just trees but foremost fungi. Except for their above-ground fruiting bodies that we call mushrooms, fungi largely weave their way unseen through soil, decaying wood, and other substances. Here, they form mycelium: networks of fine tubular cells. Many fungi live in symbiosis with plant roots, forming mycorrhizas (combining the Greek words for fungus and root). Mycorrhizas connect plants and fungi into sprawling networks that play a role in plant nutrition and soil chemistry, though not all interactions are necessarily mutualistic (i.e. beneficial to both partners). There are various types of mycorrhiza, but important to this book are ectomycorrhizal fungi. They are predominantly associated with woody plants and envelop plant roots in a sheath of fungal cells. By the 1980s, researchers such as David Read (and others before him) had shown that chemicals can pass between plants via these fungal pathways. Simard would pick up on this discovery and run with it.

Interestingly, Simard was born in a family of loggers and, before entering academia, worked for a logging company and later the Forest Service of British Columbia. She thus experienced up close the government’s standard forestry practice, their free-to-grow policy. This means that plantations are actively cleared of native plant species using herbicides and mechanical means so that Douglas fir and other lucrative trees are “free to grow” without competition. Why, then, were so many seedlings failing?

“Easily the strongest suit of Finding the Mother Tree is the story of the uphill struggle of a young woman in the masculine world of Canadian forestry […]”

Easily the strongest suit of Finding the Mother Tree is the story of the uphill struggle of a young woman in the masculine world of Canadian forestry to try and convince them that their approach is misguided. Simard excels at describing her experiments and the rationale behind them in an understandable way. Some of her main findings are that removing native trees such as birch only provides short-term benefits to fir but leaves them more vulnerable in the long run. Starting from her suspicion that fungi have something to do with this, she discovers how birch and fir exchange carbon and nitrogen via mycorrhizal networks and can swap roles as source and sink over the seasons. Allowing fir and birch to grow together results in richer fungal communities and protects fir from pathogenic fungi. Digging deeper into fundamental aspects of mycorrhizal fungi, she notices that older and younger firs are connected underground, and hits on the idea of mother trees nurturing their offspring. Further work shows how fungal networks allow for warning signals to be communicated, kin to be recognized, and how dying trees might even off-load nutrients to younger trees. In an industry that sees trees as a commodity and focuses on short-term benefits and maximizing profit, her findings are not particularly welcomed and heavily scrutinized. She has faced plenty of abuse in the process.

The other, perhaps less expected part, is that Finding the Mother Tree is also a memoir in which Simard writes openly of her personal life. It is not until chapter 5 that you get to the first research, the preceding chapters telling of her family and childhood. In later chapters, the science sometimes takes a backseat to her life story, which is a shame as this is when her findings become more open to interpretation.

“Take the phrase “mother tree”. Beyond masking a biology quite unlike our own […] in scientific publications […] she instead talks of “hub trees” which evokes network topology. Quite the difference, no?”

My beef with this book is three-fold. First is its tone. Though she does not go as far as Peter Wohlleben did in The Hidden Life of Trees (and for which he was )^[1] some of Simard’s language and metaphors are emotive and value-laden. The introduction is full of words such as “ancient”, “wisdom”, and “healing”. No doubt her message will resonate with readers of Braiding Sweetgrass and Lessons from Plants, but when she concludes that “the forest is wired for wisdom, sentience, and healing” (p. 6), I cringed. Why, yes, I do have a giant chip on my shoulder regarding overt spirituality—I cannot deny my bias. In all seriousness, though, take the phrase “mother tree”. She admits that they are “mother and father trees, since each Douglas-fir tree has male pollen cones and female seed cones. But… it felt like mothering to me” (p. 228). Beyond masking a biology quite unlike our own, you would not get away with such emotive language in scientific publications. There, she instead talks of “hub trees” which evokes network topology. Quite the difference, no? But it is not a word you will find in this book. It contributes to my impression that this is Simard’s platform to share her beliefs and speculate to her heart’s content, unhindered by peer review.

This leads to my second objection: I have no issue with her experiments and results (I think she has done amazing work over the years), but I question some of her interpretations. For example, having explained concepts such as turgor pressure, source–sink gradients, and pressure-flow in chapter 8, she then mentions how birch transfers carbon to fir. Birch transfers more carbon when shading the fir and hindering its photosynthesis, i.e. when there is a steeper concentration gradient between the two. Can we really conclude from this that “birch was detecting and staying attuned to the needs of fir” (p. 160), or is this just simple physics? What she does insufficiently, in my opinion, is discuss how her ideas have been received by the wider scientific community, how she has defended them, and what other interpretations are possible. Furthermore, there is not much here in the way of signposting where her ideas become speculative, such as her brainwave that mycorrhizas resemble neural networks and the chemicals zipping around them resemble neurotransmitters. These are interesting ideas, but my concern is that lay readers will unquestioningly accept them as established facts, Simard’s track record as a publishing scientist giving them an air of legitimacy. One of the best critiques I have read is the chapter on the wood-wide web in Sheldrake’s Entangled Life that raises numerous objections. For example, he points out how this plant-centric metaphor downplays the role of fungi and mentions David Johnson, who cautions against extrapolating from laboratory findings on potted seedlings to whole forests. Unfortunately, Finding the Mother Tree left me with the impression of a scientist so enamoured with how her findings align with her values and beliefs that she cannot take sufficient distance to critically interrogate them.

“The reason I object to [anthropomorphic metaphors] is not that I think animals and plants are automatons devoid of agency [but because] comparing them to us introduces a new straitjacket.”

Finally, Simard freely uses anthropomorphic metaphors and assigns agency to trees. The reason I object to this is not that I think animals and plants are automatons devoid of agency. If anything, I am convinced that we routinely underestimate them, as I hope my reviews of books such as Safina’s Beyond Words and Mancuso’s The Revolutionary Genius of Plants have shown. But comparing them to us introduces a new straitjacket. In Entangled Life, David Read argues that “utopian visions of the soil are a shameless projection of human values onto a non-human system” (p. 180). Sheldrake, I think, captures best the objection to anthropomorphism: “Are we able to stand back, look at the system, and let the polyphonic swarms of plants and fungi and bacteria […] be themselves, and quite unlike anything else? What would that do to our minds?” (p. 193).

Above criticism is not intended to pooh-pooh Simard’s work. Though I might disagree with some of her interpretations, what she has uncovered about plant–fungi interactions is truly amazing and shows there is so much more happening below-ground than we ever realised. Her book successfully shows how aggressive forestry policies do not produce the desired results and she points the way toward better practices. Indeed, understanding mycorrhizal networks can have many applications. Whether or not her concept of mother trees resonates with you, I recommend this book simply because it is a first-hand account from the woman who pioneered this research. I would, however, recommend you read it in tandem with Entangled Life for a fuller picture.

1. ↑ A 2023 publication in Nature Ecology & Evolution further critically reviewed the portrayal of mycorrhizal networks in popular media, while this July 2024 opinion piece in The Guardian charts the fall-out from that publication.

Addendum 1: Readers might also be interested in a series of episodes of the In Defense of Plants podcast where Matt Candeias interviews Melanie Jones (episode 425), Jason Hoeksema (episode 427), and Justine Karst (episode 430) to discuss what the data really tell us about mycorrhizal networks and the notion of the wood-wide web.

Addendum 2: Thanks to Graeme Miller for linking me to episode 135 of the YourForest podcast which features another excellent interview with Justine Karst that critically reviews how limited the data are that undergird the idea of the wood-wide web.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Finding the Mother Tree

Other recommended books mentioned in this review:

__________________________________________________________________

__________________________________________________________________

Throughout human history, wood has been our constant, if somewhat overlooked companion. With The Wood Age, professor of biological sciences Roland Ennos delivers an eye-opening piece of environmental history. Reaching beyond the boundaries of this discipline, it gives the reader a comprehensive picture of how we have shaped wood and how, in turn, wood has shaped us.

The Wood Age: How One Material Shaped the Whole of Human History, written by Roland Ennos, published in Europe by William Collins (a HarperCollins imprint) in March 2021 (hardback, 327 pages)

The core of The Wood Age^[1] is an environmental history as you might expect it, charting our use of wood through time, though it is driven by an interesting and, to me, novel argument: “technological advances in other materials helped people make far better use of the material they had always exploited: wood” (p. 78). In Tree Story, Trouet made a similar argument, writing that “human civilization as we know it is founded on trees” (p. 201 therein). Ennos argues that anthropologists and archaeologists have long overemphasized the importance of stone tools. Many of them were probably accessories to create better wooden tools. It is an attractive idea, though somewhat tenuous given wood’s tendency to not be conserved in the archaeological record. With later technological progress, however, this argument starts to look more and more convincing.

Take later stone axes with blunt heads made from jade, basalt, or other rocks. Although seemingly useless for chopping wood, they were excellent at splitting it. Metallurgy gave us better weapons but also better woodworking tools. Ennos charts how the refining of copper coincided with the production of the first plank ships and wheels. Iron allowed us to make the first saws and later tools such as planes and lathes. Other advances were the switch from working with freshly cut wood, so-called green woodworking, to using wood that has been allowed to dry out, or the steaming of wood to bend it. Wood allowed us to overcome the limitations inherent in large stone structures—Ennos even writes that “the history of architecture can be seen as the development of increasingly effective techniques to harness timber to stabilize and shelter ostensibly stone buildings” (p. 156). We shaped wood ever more precisely, making everything from furniture and household items to beautiful musical instruments such as violins and guitars.

Even the Industrial Revolution did not spell the end of wood. Wrought iron allowed metal joints to be incorporated into larger wooden structures, while the invention of industrial machines gave us mass-produced nails and screws, making everyone a carpenter. Wood pulp fed a booming newspaper and book industry and we engineered wood into new materials such as plywood (which saw a surprising use in early aeroplanes), chipboard (on which IKEA built its flatpack furniture empire), fiberboard, cardboard, and, more recently, laminated wood (glulam) and crossed-fibre laminates that are used to make the enormous beams seen in large halls and wooden high-rise buildings.

“The Wood Age is an environmental history […] driven by an interesting […] argument: ‘technological advances in other materials helped people make far better use of the material they had always exploited: wood’“

For all its miraculous properties, an interesting argument that Ennos develops here is that wood also locked us in a period of technological stasis. The Romans already hit upon the limits of what could be achieved with wood, with e.g. ships and roof trusses not increasing in size with time. Given the poor state of roads, transporting wood over any appreciable distance was expensive. Only port cities or those along navigable rivers could easily float wood in from further away. This also meant that many fuel-intensive industries that produced e.g. glass, soap, iron, or gunpowder were scattered throughout forests, close to their fuel source. There was a literal disconnect between craftspeople and the burgeoning class of scholars at universities and little exchange of knowledge. Though, as mentioned elsewhere, craft guilds also had a role to play in stifling innovation. It was not until some countries hit upon fossil fuels that this technological deadlock was broken. The Dutch built a brief Golden Age on the back of peat, but it was the English and the coal-stoked Industrial Revolution that would change the world forever.

Ennos has previously written about both trees and biomechanics. His background knowledge has seeped into this book as he delves into a fair bit of materials science, metallurgy, architecture, and woodworking. Though his explanations are clear, the only minor complaint I had was the use of unfamiliar terminology. The plates section offers some illustrations, but I still found myself looking up certain woodworking joints (e.g. dovetail joints), architectural terms (e.g. hammer-beam roofs), or tools.

This point aside, what elevates this book beyond “merely” a solid piece of environmental history are the chapters that bookend the core. The first three chapters are an unexpected dive into primatology, showing our deep affinity with trees. It is pretty well known that various great ape species fashion tools out of sticks, but fewer people might be familiar with the treetop nests in which they sleep. Furthermore, Ennos considers the evolution of bipedalism. Might it have evolved in the treetops when walking along branches? This was one of several ideas discussed, though not favoured by, Begun in The Real Planet of the Apes. And he briefly touches on the limb anatomy of Danuvius guggenmosi and Ardipithecus ramidus (especially its big toe, such a bone of contention in Fossil Men).

“Ennos has previously written about both trees and biomechanics. His background knowledge has seeped into this book as he delves into a fair bit of materials science, metallurgy, architecture, and woodworking.”

At the other end, the penultimate chapter takes aim at what Ennos calls deforestation myths. A superficial reading suggests he is contradicting himself as he next outlines how much impact we have had. However, what he takes issue with is the narrative told by the likes of Jared Diamond that deforestation led to environmental catastrophe and eventual civilizational collapse. The idea that felling trees results in catastrophic soil erosion is based on modern industrial forestry practices, he claims, “our impressions exaggerate the historical extent of the problem” (p. 246). Ennos in no way suggests that deforestation itself is somehow a myth: “environmental historians are starting to realize that even before industrial times our impact was enormous” (p. 258). “Virgin” rainforest has long been under cultivation and there is a clearly documented decrease in both forest cover and species diversity with time, with practices such as plantation forestry and species translocations adding further insult to injury by introducing plant pests and diseases. Indeed, writes Ennos, the only times when forest cover rebounded in Europe and the Americas was after major events such as the fall of the Roman Empire or pandemics.

Looking ahead, high-tech uses of wood have the potential to replace steel and concrete though I appreciated Ennos’s scepticism. Such wood products are energy-consuming to fabricate, while technofixes “continue to move our juggernaut economy even further along the path of unlimited economic growth” (p. 272). Instead, he has several suggestions by which we could make trees part of our lives again and so undo the disconnect that has grown between people and forests.

The Wood Age is an eye-opening piece of environmental history that considers a wide range of topics and is particularly strong on the materials science aspect of wood. It joins a recent crop of excellent books on trees and forests and, if you enjoyed any of these, comes highly recommended.

1. ↑ Thanks to Andreas from Reißwolf for highlighting it was first published in the US market in 2020 by Scribner as The Age of Wood. Hence the book’s use of degrees Fahrenheit and other imperial metrics throughout.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

The Wood Age

Other recommended books mentioned in this review:

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

What is the price of humanity’s progress? The cover of this book, featuring a dusty landscape of tree stumps, leaves little to the imagination. In the eyes of French journalist and historian Laurent Testot it has been nothing short of cataclysmic. Originally published in French in 2017, The University of Chicago Press published the English translation at the tail-end of 2020.

Early on, Testot makes clear that environmental history as a discipline can take several forms: studying both the impact of humans on the environment, and of the environment on human affairs, as well as putting nature in a historical context. Testot does all of this in this ambitious book as he charts the exploits of Monkey—his metaphor for humanity—through seven revolutions and three million years.

Cataclysms: An Environmental History of Humanity, written by Laurent Testot, published by The University of Chicago Press in November 2020 (hardback, 452 pages)

To be frank, Testot deals with the first 2,988,000 years in the first two chapters. Understandably, as the pace of progress was initially slow, and comparatively little information is available to us from the palaeontological and archaeological records. Thus, he starts his history proper with the agricultural revolution ~12,000 years ago. Given the synthesizing nature of this book, Cataclysms will be a feast of recognition for readers that are familiar with the literature.

Some examples include the near-simultaneous rise of agriculture in several places, with geography playing an important role in which plants and animals were available to domesticate, or the fall of the Late-Bronze Age civilizations in the 12th century BCE. The myth of virgin rainforests and the long history of agriculture practised in the jungle. The microbiological onslaught that accompanied the Columbian exchange when Christopher Columbus and other explorers brought new epidemics to the Americas, or the scourge of mosquito-borne diseases that later decimated European colonialists overseas. The medieval Little Ice Age and the global crises it precipitated, or the worldwide impact of the Tambora volcanic eruption. The Great Acceleration in the 20th century and the recognition of the Anthropocene. All of these have been chronicled at length in books and other publications.

“Given the synthesizing nature of this book, Cataclysms will be a feast of recognition for readers that are familiar with the literature.”

Testot also mentions episodes that I was barely familiar with; partially, I suspect, because he can draw on the French history literature. For example the eruption of the Samalas volcano that seems to have served as a transition between the Medieval Warm Period and the Little Ice Age. Or the 15th-century mining for silver in the Andes and the immense pollution that caused. Or the environmental roots of the expression “mad as a hatter” (it involves the 17th-century beaver trade). Cataclysms sometimes seems to forget it is an environmental history book. Thus, the environment takes a backseat when he describes the Axial Age, the period between 800 and 300 BCE that saw the birth of universal religions and philosophies in both Asia and Europe that are still with us today. Similarly, the chapter charting the rise of money, empires, and trade in Europe and Asia before the Common Era only at the very end examines the environmental impact of it all.

The book’s style might divide opinions. Testot throws all his eggs in the proverbial narrative basket. The book is clearly deeply researched, but the notes section at the end encompasses a mere 16 pages. Testot must have decided that supporting every claim and fact with a footnote would have distracted from the story he tells. Although the references contain many interesting books and publications, those wishing to check up on certain claims will have to do their own research. Furthermore, the book is strikingly devoid of photos, maps, graphs, and tables, bar a single chart of the human world population through time in the appendix. As such, I felt Cataclysms did not deliver on the dustjacket’s promise of providing “the full tally” the way e.g. Vaclav Smil did in Harvesting the Biosphere. Those wanting a more data-driven overview will probably want to check out Cataclysms‘s big contender for 2020, Daniel R. Headrick’s Humans versus Nature. I had the chance to rifle through a copy, though not yet read it in full. At 604 pages with a 100-page notes section (and some illustrations), it promises to be a denser read.

“[The book] will undoubtedly charm newcomers to the field with its narrative style and ambitious scope […] but I suspect that seasoned readers will crave something more dense and data-heavy.”

Testot’s outlook for the future is bleak, though his concluding chapter wanders somewhat aimlessly. Rather than offering an overview of which planetary boundaries we have breached and how far in overshoot we are, Testot focuses on what he calls the upcoming Evolutive Revolution before turning to some likely consequences of climate change. This final revolution could either pan out as the pipe-dream of transhumanism where nano-, bio-, and information technologies converge into the singularity that would make humans immortal / obsolete as Artificial Intelligence takes over (something Testot is critical of), or we may end up as mutants in the chemical cesspit that we are making of our planet. Throw in a conclusion and an epilogue to the English edition that both reiterate main points from the book, and it starts to feel a little bit like Tolkien’s struggle to let the reader go in the last book of The Lord of the Rings.

Environmental history has become a rather crowded subject and opinions will probably be divided on whether Cataclysms stands out from the crowd sufficiently. It will undoubtedly charm newcomers to the field with its narrative style and ambitious scope—Testot knows how to spin a fine yarn and provides an entry point to many fascinating chapters in world history that readers will want to explore further. I certainly enjoyed reading it, but I suspect that seasoned readers will crave something more dense and data-heavy.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Cataclysms

Other recommended books mentioned in this review:

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

The legendary British broadcaster and natural historian Sir David Attenborough needs almost no introduction. Since his first appearance on our television screens in 1954, he has gone on to a long and distinguished career presenting and narrating groundbreaking nature documentaries. And he shows no sign of slowing down. His voice and style have become so iconic that he has been dubbed the voice of nature. Over the years, he has increasingly expressed concern over the state of the natural world, and in A Life on Our Planet Attenborough fully engages with this topic. However, when you turn to the title page you will notice the name of a co-author, Jonnie Hughes, who directed the Netflix documentary tied in with this book. As Attenborough explains in his acknowledgements, Hughes has been particularly instrumental in the writing of the third part of the book, together with substantial assistance from the Science Team at WWF. This is Attenborough’s witness statement, yes, but whose vision of the future is it?

A Life on Our Planet: My Witness Statement and a Vision for the Future, written by Sir David Attenborough with Jonnie Hughes, published by Witness Books (an imprint of Ebury Press) in October 2020 (hardback, 282 pages)

A Life on Our Planet is divided into three parts, the first of which features highlights from Attenborough’s filmmaking career. Interwoven with vignettes that you might recognize from his autobiography are short episodes in the history of life on our planet and the rise of human civilization—this is Attenborough writing at his finest. Overlaid is his increasing concern for the changes he has witnessed. Each chapter heading ominously lists the human world population, the atmospheric carbon level, and the estimated percentage of wilderness remaining in a certain year.

The brief second part, “What Lies Ahead”, serves as a bridge to the third part and introduces several important concepts. One is the Great Acceleration, the period following the 1950s in which our activity and impact on the environment ramped up tremendously. The other is the Planetary Boundaries model drawn up by Johan Rockström and colleagues, which I brought up in my previous review of Planetary Accounting. This Earth systems science framework demarcates a “safe operating space for humanity” by identifying nine planetary processes and systems with their boundary values, several of which we have exceeded with our actions. In just ten pages, the book then looks ahead to some likely environmental tipping points in our near future, such as forest dieback and permafrost melting. I was expecting a longer section along the lines of Lynas’s Our Final Warning and Wallace-Well’s The Uninhabitable Earth, but clearly, this book has no interest in dwelling on the catastrophes ahead.

“Interwoven with autobiographical vignettes are short episodes in the history of life on our planet and the rise of human civilization—this is Attenborough writing at his finest.”

This brings us to the vision for the future, which is where the question of authorship becomes increasingly blurred. At times I was not sure whether I was reading Attenborough’s voice or a WWF policy brief. The book takes the planetary boundaries model with its ecological ceiling and Kate Raworth’s modification known as the Doughnut model, which adds a social foundation to it, i.e. the minimum requirements for human well-being. It then outlines some of the changes required to significantly reduce our impact on the planet, leaning towards “green” and nature-based solutions aimed primarily at restoring biodiversity. The overall tone here is hopeful and the book hits many relevant points, though I have some criticism.

Let’s start with what I appreciated. First, and this feels like Attenborough speaking, it gets its philosophy right, tackling anthropocentrism: “We moved from being a part of nature to being apart from nature […] we need to reverse that transition” (p. 125). It also acknowledges the shifting baseline syndrome in the context of fisheries and beyond: how each generation takes an increasingly impoverished environment as the new normal. Right out of the gate it tackles the need to move beyond the paradigm of perpetual growth and abandon Gross Domestic Product as our prime measure of welfare. Agriculture will have to rely on far less land through solutions that are high-tech (e.g. hydroponic greenhouses run on renewable energy), or low-tech (e.g. a shift away from monocultures to something more approaching functional ecosystems via regenerative farming and the growing of mixed crops). Most important would be a change from a meat- to a plant-based diet. Attenborough again: “When I was young […] meat was a rare treat” (p. 169). We should want less stuff and require our things to be repairable and recyclable, moving ultimately towards a circular economy. This all ties in nicely, although it is not spelt out here, with an ethos of self-limitation that we need to reclaim.

“This brings us to the vision for the future, which is where the question of authorship becomes increasingly blurred. At times I was not sure whether I was reading Attenborough’s voice or a WWF policy brief.”

Carbon capture will have to be achieved not by high-tech solutions, but by both reforestation on land and the farming of kelp forests in the sea (Ruth Kassinger already made the point in Slime that algae might just save the world). Both these solutions will help the massive rewilding efforts this book envisions: Marine Protected Areas will help fish populations to recover, resulting in sustainable fisheries, while on land more habitat will become available for wild animals. And, finally and importantly, the book tackles human population numbers, aiming for the humane solution of stabilising the world population as quickly as possible at 9–11 billion people by lifting people out of poverty and empowering women.

The holistic package proposed here, underpinned with examples of success stories from around the globe, almost makes it sound like we can have it all. Can we? The authors acknowledge that many of these transitions will not come easily and will require everyone to come together and cooperate (in itself a tall order). Where achievability is concerned, the devil is in the details, and I do feel that these are sometimes glossed over and that taboo subjects are avoided.

Take agriculture—there is no mention of the tremendous potential of genetically modified organisms. Similarly unmentioned regarding renewable energy is the concept of energy density and our reliance on increasingly energy-dense fuels as civilization progressed. There is no consideration of the tremendous amount of resources needed to build and maintain the necessary infrastructure. A combined solution of renewable and nuclear energy (admittedly a non-renewable) is considered a no-no. And though a circular economy is a step up from our linear system of produce-use-discard, you cannot endlessly recycle: a constant influx of virgin material is required. Not all metals can be economically recovered, nor all the compound materials we make unmade. Ever tried unfrying an egg? Entropy does not run that way.

“The holistic package proposed here […] almost makes it sound like we can have it all. Can we? […] these transitions will not come easily and […] the devil is in the details.”

The word “overpopulation” is studiously avoided, which is remarkable as Attenborough has been outspoken on the subject elsewhere (see this short explainer or the 2011 RSA President’s Lecture). The closest he gets to it here is when he writes that “we have overrun the Earth” (p. 100). Later, the possibility of a demographic transition to a declining world population is mentioned, but not the suggestion put forward by some that a lower world population of, say, 2–3 billion might be more sustainable. And though Attenborough points out increased longevity as a contributing factor, there is no examination of our relationship with death. Should we really direct all our efforts to maximising life span? At what cost, both environmental and quality-of-life-wise? And, lastly, the now-dominant narrative of female empowerment is only half the story and puts the onus squarely on their shoulders. Making contraception and abortion available to women is needed, but better still would be to prevent pregnancies by starting with male education. Condom, gentlemen?

Admittedly, I am arguing details here. Though they need serious consideration in my opinion, much of what is proposed here is sensible. A Life on Our Planet is very accessible and admirably concise. Its central message, that things cannot continue as they are, stands. If there is anyone who can communicate this to a wide audience, it is Sir David Attenborough. Some of the writing here will stick with you long after you have closed the book: “We often talk of saving the planet, but the truth is that we must do these things to save ourselves.” (p. 218). Here speaks a wise elder who, even at 94, indefatigably defends our environment.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

A Life on Our Planet

Other recommended books mentioned in this review:

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

What I am about to write is probably going to upset many people, but… I am growing frustrated with the narrative of much of the environmental movement. Taking to the streets to protest and demand change, to “do something!”, is all fine and dandy, but it is also a bit hypocritical. It fosters a narrative in which the onus is always on others and it begs the counter-question: “what are you willing to give up?”. That is the hard question.

There, I said it. You have the option to stop reading now.

In all seriousness, if we want to avert dangerous climate change or allow forests to recover from deforestation, how much change is enough? How much are we allowed to consume? Planetary Accounting will not offer you final prescriptive answers, but it is an important first step in quantifying per capita quota for what each of us can consume and pollute without it costing the planet.

Planetary Accounting: Quantifying How to Live Within Planetary Limits at Different Scales of Human Activity, written by Kate Meyer and Peter Newman, published by Springer in March 2020 (hardback, 290 pages)

This book follows on perfectly from Kallis’s Limits that I just reviewed, which urged for a culture of self-limitation. The immediate follow-up question then is: how much? In Planetary Accounting, sustainability scientists Kate Meyer and Peter Newman take the planetary boundaries framework as their starting point and translate it into planetary quotas. If the former can be likened to a patient’s diagnosis, the latter can be interpreted as the doctor’s prescriptions: here is the amount and direction of change needed.

In case you are not yet familiar with it, the planetary boundaries framework was developed by Johan Rockström and colleagues and presented in a 2009 Nature paper, followed by a book for a general audience in 2014, and further refinements proposed in a 2015 Science paper. It is an Earth systems science framework that demarcates a “safe operating space for humanity” by identifying nine planetary processes and systems with their boundary values. Think climate change, biodiversity loss, or ozone depletion. For several of these, we have crossed the limit and are collectively pushing our environment towards a new state that is likely to be a lot less friendly to human life. A case is even being made that we have entered a new geological epoch, the Anthropocene.

You might ask why it matters that we emit more nitrogen and phosphorus into our environment than we should, or are seeing species extinction rates far above background values. Surely, our world always changes and is not a museum piece. Consider the following, I think very interesting, argument. Some authors propose that it took the stable climatic conditions of the Holocene for civilization to take off. Not because climate drove civilization—humanity was rearing to go—but because we needed a stable window of opportunity. Meyer & Newman mention Cook’s A Brief History of the Human Race, but I came across this same argument in Dartnell’s Origins where he suggested that there may have been earlier attempts at migrating out of Africa or developing agricultural civilizations, that simply fizzled out before taking off because environmental conditions were unfavourable. Rockström and colleagues argue that the state of the planet during the Holocene is the only one we know of in which settled societies can thrive. Whether we can in other environmental states is unknown, nor do we know what new balance the Anthropocene will reach. So, how lucky, really, are we feeling?

“it took the stable climatic conditions of the Holocene for civilization to take off. […] Whether we can [thrive] in other environmental states is unknown […] So, how lucky, really, are we feeling?”

This introduction is accompanied by a very capable routing of the arguments of climate change denialists and a brief exploration of other environmental impact assessment frameworks before Meyer & Newman turn to the limits of the planetary boundaries framework. One issue is that it describes the problem, but does not prescribe solutions. Some translation is needed and to that end, Meyer & Newman here propose the planetary accounting framework.

The bulk of the book describes this framework and develops quotas for each of the nine planetary boundaries, though it should be noted that readers might have to turn to supporting publications, including Meyer’s PhD thesis, for more details. What this exercise reveals is interesting. Four planetary boundaries have been exceeded, three not yet, and for two we lack information. The planetary quotas calculated here show we exceed seven, are at the limit of one and lack information for the last. If that seems confusing, remember that boundaries describe the state of the planet and quotas our annual impact. Some boundaries will be breached soon if we maintain current rates.

To illustrate this with an example. For climate change, one planetary boundary is an atmospheric carbon dioxide concentration of 350 ppm (parts per million), which has been exceeded. The corresponding quota is based on CO₂ emissions, expressed in gigatonnes. To meet the target of the IPCC climate change scenario that the authors have selected (limit global warming to +1.5 °C by 2100) we should change our emissions from the current +36 to -12 GtCO₂/year. This is an example where we should not just reverse direction (i.e. emit less), we should be actively removing atmospheric CO₂. Deriving quotas for all boundaries is not necessarily straightforward and Meyer & Newman have drawn on the knowledge of a large body of specialists when developing the planetary accounting framework, with caveats, justifications, and assumptions described here.

“[The planetary boundaries framework] describes the problem, but does not prescribe solutions. Some translation is needed and to that end, Meyer & Newman here propose the planetary accounting framework.”

Each chapter also gives suggestions on how these quotas can be achieved at different levels (from individuals to nations) and in different sectors (communities, governments, and businesses). They call their approach poly-scalar. Although this is a first step in translating planetary boundaries to something more actionable, you will notice that this is still several steps away from usable advice. The authors acknowledge that more work is needed, that there are different ways to achieve these quotas, that the quotas are moving targets subject to revision, and that there will be a lot of political and ethical horse-trading when it comes to deciding who has to sacrifice what (especially in the developed vs. developing world). In short, they have laid out the total amount of change needed but how we are going to achieve this is yet to be decided.

I have two points of criticism. First, with the book itself. Though accessibly written, it suffers noticeably from typos and spelling errors that should have been picked out in the editorial stage. Furthermore, seeing the importance of the subject matter, the book is exorbitantly priced, probably putting it out of reach for many readers. I recommend you also have a good look at the website of The Planetary Accounting Network, the non-profit that Kate Meyer founded after completing her PhD.

My second point of criticism is with the planetary accounting framework, which has its limitations. There is no mention here of non-renewable resources: all the ores and other minerals we extract from the planet’s crust, many of which, such as rare metals, are vital to the technological solutions we envision will help us address environmental problems. Whether their framework can be expanded and adjusted to account for these is questionable, seeing such resources are finite. Furthermore, Meyer & Newman are conspicuously silent about overpopulation, although occasionally mentioning that quota sizes will depend on future population growth. I know that I am starting to sound like a stuck record, but should there be a population quota? Depending on living standards plugged into your equations, some authors have tentatively concluded that 3 billion is a more sustainable limit and that we cannot justify having more than one child.

Of course, it would be unreasonable of me to expect their framework to be a cure-all—they acknowledge it is not “one supersystem to solve everything”. Keeping that in mind, Planetary Accounting is a first step in translating the planetary boundaries to something more actionable, and Meyer & Newman provide a valuable roadmap that I expect will be widely welcomed.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Planetary Accounting

Other recommended books mentioned in this review:

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

We tend to think of forests as static. Trees, after all, do not move. But that is a perspective foisted upon us by our limbed existence. Science reporter Zach St. George unmasks this illusion in plain terms: when trees die or new ones sprout, the forest has moved a bit. “The migration of a forest is just many trees sprouting in the same direction” (p. 2).

There is no shortage of books on trees, but this sounded like such an unusual take on the subject that I was utterly stoked when I learned of The Journeys of Trees. A journalist who delves into the palaeontological record to consider the slow-motion movement of forests over deep time? Get in here!

The Journeys of Trees: A Story about Forests, People, and the Future, written by Zach St. George, published by W.W. Norton & Co. in August 2020 (hardback, 244 pages)

The question of where in space and time organisms live where they do, and don’t where they do not, is the purview of the academic discipline of biogeography. St. George’s handling of ecological concepts here is excellent, especially when considering the many unknown factors that keep a tree from growing somewhere, or his clear breakdown of different niche concepts (his description of Hutchinson’s fundamental niche as a multidimensional hypervolume is fascinating). He traces the interest in questions of biogeography back to 18th-century naturalists such as Alexander von Humboldt, Asa Gray, and Darwin and Wallace. It was not just dinosaurs that fossil hunters unearthed, but also fossil trees, revealing that they had grown in places they now no longer did.

There are spine-tingling peeks into the deep past sprinkled throughout this book. Giant sequoias—today restricted to a few groves in North America—once towered over trees from Alaska to Europe while the quintessentially British oak spend the Pleistocene ice age in Spain and France. He mentions the ecological anachronisms of plants that have become marooned when their pollinators went extinct. Or, and this one blew my mind, the striking pattern seen in forest invasions. Time and again, tree species on one continent succumb to insects or fungi native to their sister species on another continent. This hints at the boreal forest that once ringed the globe at northern latitudes and connected these forests. As St. George explains, each continent now has its own oaks, maples, chestnuts, pines, etc. evolving separately, but their shared history is recent enough that they are still vulnerable to each other’s pathogens and pests.

“There are spine-tingling peeks into the deep past sprinkled throughout this book […] and I would have happily had St. George discuss nothing but palaeobiogeography.”

Through these examples, St. George cultivates a mindset that Marcia Bjornerud has called “timefulness“. For me, this is the rare, vertigo-inducing sensation where you find yourself peering down the yawning chasm of deep time and, for just a fleeting moment, connect with its incomprehensible vastness. Not many books manage to induce this and I would have happily had St. George discuss nothing but palaeobiogeography. However, there are two important topics linked to the present and the future that almost eclipse his writing on the ghosts of the past: the burden of invasive species and the question of forest conservation in the face of future climate change.

Plants do not just move themselves, we are increasingly doing the moving for them. While naturalists and geologists were still getting to grips with the age of the Earth and concepts such as biogeography, the Industrial Revolution was busy producing its legacy of Victorian plant hunters filling up botanical gardens and private collections in Europe, and entrepreneurs moving trees to improve colonies overseas. One such thread that St. George follows here is the story of how the Monterey pine growing in California and Mexico ended up blanketing New Zealand.

But each such translocation is an experiment. We take species out of their evolutionary context at our peril. Each journey that moves plants, wood, or even soil brings the risk of unwanted stowaways. Only a minority of translocated species become a problem, but with global trade and travel having increased exponentially, so have the risks posed by invasive species. A recent example recounted here that came to light only in 2001 is the decimation of North America’s ash trees when they fell victim to the emerald ash borer, a small beetle imported from Asia, possibly in pallet wood.

“it is exactly [the] legacy of species invasions that is now causing great tension […] when considering the future of the world’s forests, [particularly] the conservation initiatives taking matters in their own hands by planting trees in new areas.”

As St. George highlights, it is exactly this legacy of species invasions that is now causing great tension in the academic and conservation communities when considering the future of the world’s forests. As the deep-time perspective of The Journeys of Trees already reveals, forest migration is closely linked to climate change, and there is plenty of that in store, with St. George highlighting the risk of exacerbated droughts and fires in particular. One difference with past climate change is that in the geologically speaking short intervening time we have laid claim to vast swathes of the Earth’s surface, largely deforesting it.

Thus, the third and final important form of forest migration that St. George considers here are the conservation initiatives taking matters in their own hands by planting trees in new areas, often in the face of caution urged by ecologists. This varies from “assisted population migration” where trees are planted in their current range, to forward-looking initiatives better labelled “assisted range expansion” where they are planted outside of the current species’ range. St. George discusses Connie Barlow’s Torreya Guardians project that is planting Florida torreya all over North America, and the living seed bank of giant sequoias created by timber company Sierra Pacific Industries.

The flap text on the dust jacket mentions that the book focuses on five trees, but the story defies any rigid or chronological organisation, looping round in circles and delightfully intersecting its own narrative in numerous places. Much as I had hoped, The Journeys of Trees ended up being a fascinating sylvan road trip that sets itself apart from the many books written on trees, not least by its deep-time perspective.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

The Journeys of Trees

Other recommended books mentioned in this review:

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

Charismatic as big cats might be, their origins and evolutionary history are still not fully understood. In a mind-bogglingly beautiful marriage of art and science, On the Prowl provides a current overview of big cat evolution that will have many a book lover purring with pleasure.

On the Prowl: In Search of Big Cat Origins, written by Mark Hallett and John M. Harris, published by Columbia University Press in June 2020 (hardback, 259 pages)

Before I even get to the contents of the book I simply have to first highlight the artwork. On the Prowl is authored by naturalist and scientific artist Mark Hallett and geologist and emeritus curator John M. Harris, with Hallett additionally providing artwork. And these are not mere pretty decorations.

Oh my, where do I even begin?

This is the rare category of tastefully executed scientific illustrations: anatomical drawings, behavioural sequences, phylogenetic trees, maps, reconstructions of life appearance, and beautiful full-bleed (i.e. printed edge-to-edge) pictures opening each chapter. Every drawing, full of detail, has been carefully crafted, has a function in the book, and has been drawn in the same tasteful pencil-sketch style. Jaw-dropping? Gob-smacking? You pick your favourite superlative—I was floored when I first opened this book. Basically, do not browse through this if you were planning not to buy more books this month, because it will be very hard to put it back down.

But what of the actual writing? On the Prowl spends five chapters tracing the outline of big cat evolution during the last 23 million years. The last three chapters deal, notably, with recent declines and extinctions, and current conservation concerns. The focus here is on the pantherines or subfamily Pantherinae; the lions, tigers, jaguars, leopards, and snow leopards. Not discussed in as much detail and acting more as supporting cast are the Felinae (pumas, cheetahs, and smaller genera such as lynxes, ocelots, clouded leopards etc.) and the various sabertoothed cats. Seeing the number of books already dealing with these (Anton’s Sabertooth and the two edited collections from Johns Hopkins University Press) it is easy to agree with their decision not to focus any further on sabertooths here.

“I simply have to first highlight the artwork […] This is the rare category of tastefully executed scientific illustrations […] I was floored when I first opened this book”

The story of pantherine evolution is far from fully resolved, and this part of the book required close attention and occasional rereading. The various lineages and subspecies, notable fossil finds, and competing hypotheses all make for a rather complicated story full of details. I should add that I am not faulting Hallett and Harris’s writing, as they do an admirable job distilling a lot of technical literature into a very readable book. It is simply that, much as we might like a good narrative, reality is often unruly and does not yield to a clean, neat story. Biology is messy like that. But what a story it nevertheless is!

An introductory overview gets you up to speed on early carnivore and carnivoran evolution and explains the difference between the two. The first cat-like species you then meet is the genus Proailurus, which (likely) evolved into Pseudalaerus, the potential ancestor to all the big cats and the “true” sabertooth cats (the machairodontines, which includes the famous Smilodon). At the time, these faced stiff competition from the so-called “false” sabertooth cats, the nimravids and barbourofelids.

Personal revelation number one: I was ignorant of the fact that not all sabertooths are closely related (had I actually read Mauricio Anton’s Sabertooth, I would know all this). The family Nimravidae arose very early, some 50 million years ago, and is technically merely a cat-like carnivore. The subfamily Machairodontinae split off from the cat family Felidae some 16 million years ago and is technically a true cat. Despite this taxonomical distance, they came to closely resemble each other. (Whoever said that what looks like a duck and quacks like a duck, probably is a duck never heard of convergent evolution…).

“it is starting to look that the Tibetan Plateau was ground zero for the pantherines from which both the snow leopard–tiger and the jaguar–lion–leopard lineages dispersed globally.”

What probably gave the Felidae the competitive edge was changes in climate and, with it, vegetation: closed forests gave way to open woodlands and savannas. Chapter 2 describes in marvellously illustrated detail the anatomical and behavioural adaptations of the pantherines that made them such formidable hunters in these open habitats and helped them claw their way to the top. This placement of big cat evolution in the context of their ecosystems and their relationship to other animals is a recurring and very welcome theme in this book. The earliest known pantherine we then meet is Panthera blytheae, a possible ancestor of the modern snow leopard, which brings me to…

Personal revelation number two: it is starting to look that the Tibetan plateau was ground zero for the pantherines from which both the snow leopard–tiger and the jaguar–lion–leopard lineages dispersed globally. Two appendices give an illustrated overview of felids in geologic time and pantherin dispersal across the world. These are useful, but, like executive summaries, are very condensed. I would have loved a few more detailed illustrations of the various timelines over which this happened, breaking out the individual lineages.

Now, connoisseurs might have immediately perked up their ears when hearing of this book. How does it compare to the 1997 book The Big Cats and their Fossil Relatives? This was, incidentally, also published by Columbia University Press, and similarly combined beautiful artwork with accessible text. It is one of the first things the authors tackle, writing that it focused more on the true felid and the nimravid cats, and comparing the books indeed confirms this. I can see two reasons why owners of the 1997 book want to pick up this one as well. One is that it fills you in on the intervening 23 years of scientific research, especially that coming out of the Asian palaeontology community. Panthera blytheae was only discovered in 2010, and pinpointing the Tibetan Plateau as the centre of pantherine radiation strikes me as a significant advance in our understanding. Two, On the Prowl spends a substantial chunk dealing with both recent extinctions and conservation concerns, something that the previous book mentioned only briefly at the end.

“Having told the story of big cat evolution, it would have been an oversight to turn a blind eye to the massive losses caused by human greed and cruelty.”

Having told the story of big cat evolution, it would have been an oversight to turn a blind eye to the massive losses caused by human greed and cruelty. Thus, these chapters and their no-punches-pulled tone are fully justified. One chapter focuses on the early decline following the last ice age, in particular discussing the decline of the steppe lion (of the four discussed extinction scenarios, only one involves humans). I was somewhat surprised to see only minimal mention of Paul Martin’s overkill hypothesis when drawing a comparison to the fate of the American lion, Panthera atrox, and no mention at all of End of the Megafauna that critically discussed it. A second chapter picks up the story of extinction with the slaughter of big cats in Roman amphitheatres and habitat destruction ever since agriculture took off some ten thousand years ago. It also prominently mentions the huge impact of trophy hunting by western colonialists in Africa and Asia. The last chapter highlights the ongoing threats of poaching and wildlife trafficking (particularly slamming tiger farms in China and the canned lion hunting industry in Africa), human-wildlife conflict between carnivores and cattle herders, the shortcomings of national parks, and reasonable and critical consideration of future options such as captive breeding, rewilding, and de-extinction.

Overall, On the Prowl provides a superb overview of the complex and rich story of big cat evolution, while being an outstanding showcase of how beautiful artwork can support science communication. I have no hesitation to recommend this book as one of 2020’s must-buy palaeontology books.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

On the Prowl

Other recommended books mentioned in this review:

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________