This is my review of two most recent books by the Italian botanist Stefano Mancuso, professor at the University of Florence and activist for the protection of plants, environment, climate and human civilisation which depends on it. Mancuso leads the International Laboratory of Plant Neurobiology, which studies plant intelligence and plant behaviour.
Don’t panic, Mancuso is certainly not claiming that plants have a brain or emotional feelings. Quite the opposite, he seeks to dispel our animal-centric view on life, and shows that plants are amazing in their own way, and in many respects much more advanced than animals. Especially more than humans, who after some measly 300k years of existence are poised to destroy the entire planet and themselves, while plants and photosynthetic bacteria have been doing exactly the opposite, terraforming and creating life for all on Earth, for a billion years already.
The two books are:
The books were originally published in Italian, but my own knowledge of the language (despite over four and a half years postdoc in Italy) suffices merely for grocery shopping. This is why I read the books in German translation, having received them from the publisher Klett-Cotta. If you don’t speak Italian or German, there are also English versions of these two books available.
Although I read his books in translation, Mancuso comes across as a gifted writer, with an engaging story-telling approach, an Italian way of a professore to entertain friends at a table. The books are written in a popular science format, the reader is not expected to have any biology knowledge whatsoever, merely an interest for nature and the living things. Yet if Mancuso makes a scientific claim, it is usually properly referenced to a research paper or other sources. The books are not long, around 150 pages each. They are both very entertaining, informative and never boring.
The Incredible Journey of Plants
This book was first published in 2018, under the title “L’incredibile viaggio delle piante“. It is illustrated with many beautiful aquarelle paintings by Grisha Fisher and is about the amazing skills of plants to colonise the Earth and to survive, skills which no animal can match. After all, it was plants which first colonised the dry land around half a billion years ago, and made it habitable for animals. But even now, it is the pioneering plants which conquer new territories, daily. Be it a newly formed volcanic island, a deserted military installation near Mancuso’s institute in Florence, the abandoned and radioactive town of Pripyat in Ukraine, or the former steel factory in my quasi-home city Duisburg, where trees grow even inside vertical walls and walkways many meters up in the air.
Plants are actually born travellers and pioneers. They produce enormous amounts of seeds and deploy all possible vectors for their dispersal: wind, water and animals. Once taken root, plants can perform the most amazing feats of survival, simply because they cannot go elsewhere as animals do. The book tells us in a series of stories how plants do it.
We tend to think of plants as immobile, but they are most definitely not. They do move, a lot actually, but on a different time scale than animals. Plants are indeed sessile, i.e. they are rooted to the spot where they were born until their death, which in some cases however is a relative thing, because plants can regenerate and clone themselves, thwarting the concept of mortality which is so daunting and final to animals.
The sessile nature of plants is what makes them so resilient and pioneering, allowing them to colonise every single corner of the earth, never mind how remote. Plants cannot run away from their predators, yet they evolved ingenious ways to defend themselves not just from animals, but also from fungi, bacteria and viruses. But this Mancuso book is about plants on the move: the colonisation via seed dispersal, and the stamina to survive when plants conquer new territory or encounter new environmental challenges.
In this regard, plants are the absolute masters in engaging animals, fungi and bacteria (probably not viruses?) into mutually benefiting partnerships. Everyone will know about the flowers and the bees, but partnerships with mobile animals and most recently with humans also allowed plant species to settle and dominate areas they would never have reached by themselves.
Mancuso tells us about plants, even trees, colonising newly formed volcanic islands with the help of birds, the plant seeds arriving from far away in birds’ stomachs or stuck to their feet. Trees of the Chernobyl exclusion area in Ukraine, where no human is allowed to live, managed to cope with dangerous levels of radiation, after an entire pine forest turned red and died in 1986 when the nuclear reactor exploded (more on this topic here). As Mancuso notes, even heavy radioactive pollution is a manageable problem for wildlife compared to the damage human presence does to the environment. Plants, especially trees, actually make the area habitable by up-taking and storing radioactive fission nuclides in their wood. That is also why forest fires in the Chernobyl exclusion zone must be avoided at all costs.
Chernobyl fallout is poppycock compared to what some trees in Hiroshima managed to survive. Mancuso tells a story how he learned of Hibakujumoku, the survivor trees of the Hiroshima atom bomb blast. These trees are revered in Japan, representing all victims of the nuclear bombings, dead and alive alike. The surviving trees stood generally one kilometre or more from the epicentre, and they are still there, alive even if damaged. One tree grew merely 370 meters from the blast site. It evaporated like the humans next to it, but then the tree returned. The roots survived the immense heat and radiation and sprouted a new trunk.
In a similar manner, the Old Tjikko spruce in Sweden managed to live to around 10,000 years so far, by growing a new trunk whenever the old one collapsed. A huge clonal forest of aspen, called Pando, grows out from the genetically-identical root system in Utah, USA. It is the heaviest living organism on Earth and estimated to be up to 14k years old (Mancuso uses the outdated estimate of 80k years though).
On top of that, even individual trees can achieve bizarre ages. Mancuso writes about the last acacia tree of the Ténéré desert in the Sahara, which must have been around 5,000 years old, from the long-gone times when trees still grew in that now utterly arid and inhospitable desert. It could have grown for further thousands of years maybe, but humans kept hitting the lonely tree with their lorries until it died.
Plant seeds in turn can survive for hundreds and sometimes even thousands of years (especially in permafrost) and still be able to germinate. Mancuso offers among his examples the extinct date palm species of the ancient Judea, which was brought to life from a two thousand year old kernel (Sallon, Solowey et al 2008). And, what rotten luck, the date tree proved to be male, so no mythical Judean dates to be expected unless someone finds and germinates a female plant.
Trees are indeed amazing survivors, and Mancuso gives more examples, like the most remote tree in the world, the lonely Sitka spruce on the Campbell Island, south of New Zealand and near the Antarctic, which is the only survivor of a silly forest planting project by the English colonial authorities. But then again, also that tree found a new habitat only thanks to using humans as vector. It also served to support the claim that Anthropocene began in 1965 (Turney et al 2018), when the fallout from nuclear tests left a clear geological trace over the planet, including in that remotest tree of all. Although I personally would be careful with Chris Turney’s clickbaity claims.
Another tree, the avocado, almost went extinct after humans arriving in the Americas exterminated the huge herbivores like mastodons and giant ground sloths who ate the avocado fruits whole and dispersed its large seeds. But then humans discovered the taste fro avocados, and became the plant’s saviours and its most successful vectors, spreading the species all over the world. Mancuso however warns of the pact with the devil, because humans don’t like seeds in their fruits, with many plants bred into sterility – the clonal Cavendish banana, which constitutes 99% of world’s crop, now threatened by a fungus, being the most notorious example. Also a seedless avocado has been bred by now, the devil is about to claim his price.
One tree doesn’t need any vectors because it doesn’t travel at all. Coco de mer (the palm tree which gigantic nut looks like a lady’s bottom) is the exact opposite of the world-conquering coconut palm and instead takes care of its offspring in a doting manner we generally know from vertebrate animals. That’s because the two Seychelle islands it grows on are so poor in soil quality that the option that tree went for, was to produce an enormous an offspring seed every ten years which drops and germinates right next to the mother trunk (there are male and female trees of this dioecious plant species). The mother tree then literally feeds its growing progeny by channelling water and nutrients from bird droppings to it, via special channels in its leafs.
It is of course not just trees which this book is about. Mancuso talks about smaller plants which managed to spread to new territories because humans found them pretty or interesting and carried them there, intentionally. Some became to be seen as pests, a notion Mancuso vehemently rejects. For him, there is not such thing as invasive species, and he keeps suggesting humans should first look at themselves, the most destructive apex predator and the most invasive species by far. And this is what his most recent book is about.
The Nation of Plants
This book, in Italian “La Nazione delle Piante“, which got the strange title in German “Pflanzen und ihre Rechte” (plants and their rights), is actually not about plants, but about humans, who are advised to learn from plants how to live and survive on this planet unless we wish to go extinct very soon, having taken everyone else with us.
Mancuso wrote a charter of plant rights, a green constitution with 8 paragraphs, which is an appeal to humans to save themselves and the planet before it’s too late. His proposal is that we should respect plants and learn from them, also because plants are very successful in everything they do.
For example, our animal-brain-centred approach to bureaucracy and hierarchies is all wrong, as Mancuso explains. A downstream command system like our institutions usually have may be fast but it is error-prone and extremely energy-wasting. Instead, human networks should be organised de-centrally, like plants operate. Plants lack defined organs as animals do, their “nervous system” does not exist in the way we understand it. Yet plants are perfectly able to perceive, react and adapt to, and even move towards or from any possible environmental factor affecting it. An animal which loses an organ or part of its body will not survive long. For a plant, losing its bits is daily life routine. Human societies which rely on a leader figure fall into disarray when something happens to the leader; those with flatter hierarchies are more robust even to the most aggressive challenges. Mancuso then names the internet as an example of a organisation modelled on plants. Internet has no central command, it is distributed over many routers and servers, a local blackout is globally never a problem. Maybe this is why the internet is such a success story?
Another thing we should learn from plants: cooperation. Social Darwinism, beloved by capitalists and eugenicists, has exactly zero to do with what actually happens in nature. Instead, cooperation is the basis of successful survival, and plants are masters of it. Think of lichen (symbiotic organisms consisting of cyanobacteria or algae and a fungus), or nitrogen-fixating bacteria living in root nodules of some plant families, or the wood-wide-web, the vast mycorrhizal network which connects trees via fungal hypha, and serves to trade sugars for water and minerals, and, most astoundingly, to share information between trees.
Mancuso also reminds of the endosymbiotic theory developed by Lynn Margulis in 1967, according to which eukaryotic cells evolved when one cell consumed a photosynthetic bacteria and instead of digesting it, formed a symbiotic metabolic relationship. The green bacteria became the chloroplast, which provided the host cell with sugars generated from sun light and CO2. Mitochondria are the other case of endosymbionts which allowed the new life forms to generate vast amounts of energy from “burning” sugars using oxygen. In short, cooperation is something we humans must urgently learn from plants, instead of constantly blathering about survival of the fittest and eugenics of wealth inheritance (example read here).
And of course we must not forget whom we owe the existence of all life on earth including ourselves: the photosynthetic plants. Without them, there obviously would be no green Earth. There would probably even be no blue Earth, because without plants climate would superheat on CO2 and all water would evaporate. Maybe we should stop destroying nature or else we will destroy ourselves?
Mancuso keeps warning the humanity to stop degrading natural habitats and soil, polluting the land and oceans, basically to stop the anthropogenic mass extinction of all living species which happens at a scale and speed never before seen in Earth’s history. We must especially stop burning fossil fuels, simply because the impending climate catastrophe will not only cause wars and famine, but may even to destroy us as a species. The botanist even has an idea how we can reduce the carbon dioxide output, by reminding us how first plants which colonised the land made the Earth habitable by bringing down the CO2 content in the atmosphere. Let’s put plants everywhere, is Mancuso’s idea, especially in the cities. Break up concrete wherever possible, and plant trees, flowers and grass, even on the roofs!
Constant economic growth is not possible given the limited resources of the planet. Again, Mancuso offers plants as example to emulate. Since plants cannot wander off in search of better habitats, they evolved many amazing ways to adapt to all possible shortages. In particular, plants can do something animals can’t: they can control their growth. Animals die when there is no enough food, plants just stop growing. I interpret it that maybe we could do without our car fetish, holiday flights, useless consume products and eating meat all day, and save the planet and ourself in the process.
Finally, Mancuso does not believe in the concept of invasive species, not for animals, not for plants, and he applies this attitude to human societies also. The Italian scientist says that migration is a normal process, including and in particular for us humans. He is appalled by the behaviour of politicians, including in his own Italy, who turn away refugees boats and oppose immigration. Mancuso says that we must accept that climate change is already happening and recognise human migration as a right, instead of barring desperate refugees from crossing our national borders.
This book about plants is actually a piece of humanist literature, with many important ideas and food for thought.
Disclaimer: As usual, I receive no payment or incentive to write this review, but I did receive the books gratis from the publisher upon request
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