Laurent Tillon – Head of Biodiversity at France’s National Forestry Office – uses an oak tree in his 277-pager Being An Oak, published by Ithaka Press  [an imprint of Bonnier Books UK], in June 2025, as a representative of biospheres around the world, to tell a story grounded in ecology and conservation, and conveying nuggets of implicit wisdom and advice to readers. These are takeaways to one and all, which will help to contribute to sustainable human existence in perfect harmony with Mother Nature. Structured quite like a biography of an oak tree named Quercus petraea by Tillon, Being an Oak is composed of 33 short chapters arranged chronologically from 1780 to 2020. The author avails of self-made, beautiful illustrative sketches of leaves, trees, insects, birds, reptiles, animals etc. to magically facilitate a travel in space and time, to the French forest in which Quercus stands. This is a rich account of arboreal metabolism and a detailed exposition of a complex temperate-forest ecosystem with its myriad symbiotic interrelationships. Tillon’s book promises to play a key role in spreading awareness. Key sections and chapters from the book are summarised hereunder by the reviewer.

1. A chosen acorn 

Quercus-as-acorn, formed by cross-pollination or self-pollination aided entirely by wind, crosses the first barrier when he escapes weevils and drops to the ground, not knowing that there are more hurdles to overcome en route to striking root somewhere. Tillon succeeds in making readers imagine Baby-Quercus [the acorn in other words] to be a ‘doer’, quite like the other creatures of the forest, which cross his path. Thanks to providential protection provided by Nature, Baby-Quercus exhibits resilience and endurance to bide his time during the harsh winter months, waiting patiently for the right moment.

Tillon meticulously describes the development of the radicle into the taproot and the secondary rootlets, the ‘prospecting’ for water, macro-, and micronutrients, the plantlet’s rise above the ground seeking sunlight, and remarks that these are wonders which go unappreciated, mysteries which have not been satisfactorily solved by scientists. The mutualistic symbiosis between the sugars-seeking fungus Leccinum and young-Quercus who is in search of trace elements, and the formation of ectomycorrhiza [a fungus-Quercus combo], enabled in a way by the water-seeking, nitrogen-fixing rhizobium bacteria, reads like a story of betrayals as blessings in disguise, a lesson in trilateral diplomacy, and an instance of serendipity.       

2. Petraea rises above the struggles…

Quercus’s surname Petraea means ‘strong as a rock’ in Latin…and speaks volumes for the sessile oak’s dogged resistance to multifarious tormenters in Nature – birds and beasts, insects and parasites, vagaries of the weather, and forest fires [natural or anthropogenic]. The vilest tormentor of them all is  the Homo Sapien! By a sheer stroke of luck, thanks to a silvicultural decision made by the ‘Little Corporal’ Napoleon Bonanparte, Quercus benefits and starts his ascent upward, gaining height, girth and depth [as above, so below], and in the process, beauty and strength, true to his name^[1]. We learn about the role Quercus has played in the hydrological cycle, this knowledge also reinforces the need for afforestation to combat water scarcity in the years to come.

Symbiosis includes parasitism and commensalism as well, in addition to mutualism [which Quercus exhibits with Leccinum for instance]. Tillon takes us through the life-cycle of a type of butterfly, dwelling at length on the voracious green oak caterpillar which prima facie comes across as a leaf-eating parasite, but it is revealed later on that it recirculates nutrients [nitrogen and phosphorus primarily] derived from Quercus’s leaves through its droppings as well as ‘leaf-wastes’, back to the oak through the decomposers [saprophytes] proliferating in the humus-rich soil.

Another instance of commensalism between Quercus and the wolf brings to light the fact that courtesy wolves which feed on herbivores [including wood-mice], the probability that an acorn will become an oak, increases. The oak tree offers refuge to several lichens, mycophagous booklice, ants, mealybugs, aphids, scorpions, beetles, spiders, inter alia, on the outer surface of its hard bark. Spiders, scorpions, carnivorous insects [as well as bats and birds] feeding on leaf-destroying caterpillars and xylophagous organisms, may be considered to be multiple instances of mutualism.  Talking of parasitism, Tillon writes about the spangle gall wasp Neuroterus which ‘scams’ and deceives Quercus, quite like cuckoos lay their eggs in unsuspecting crows’ nests; and ‘freeloading’ owls and wood doves wait for woodpeckers to bore holes in tree-trunks and rush in to occupy them!

The myriad decomposers are extremely indispensable for the functioning of a forest ecosystem. The recirculation also applies to the red-brown-yellow leaves which are shed by deciduous Quercus in the autumn…their constituents are available for uptake by the tree in the following spring, through the enriched humus.  

3. Quercus’s Swiss army knife…

Tillon uses the metaphor of a Swiss army knife to tell us about all the various defences Quercus develops to protect himself from a host of ‘attackers’.  Learning on the go, the tree fights on – weakened often but never defeated - fulfilling its life’s mission of providing a range of ecosystem services to a wide spectrum of biological entities, including humans. That includes soaking up carbon dioxide from the air and helping us rein in global warming.

The tree’s arsenal includes, inter alia, tannins as ‘insect-repellents’ to curb defoliation, ‘sunscreens’ to protect leaves in hot summers, ‘ultra-selective security guards’ and  ‘insulators against the external chill’ found in the roots and the bark; glutamic and aspartic acids [low-nitrogen] and alkaloids to deter caterpillars from munching on his leaves, starch reserves to be called upon as ‘anti-frostbites’ during harsh winters, electrical micro-discharges producing negative ions in the air  which serve to repair damaged plant tissues, and inhibit cortisol production in us humans in the spring-, and summer-months of the year.  This explains why Tillon, off and on, refers to feeling de-stressed in the company of Quercus!

Forests the world over, including the one in which Quercus stands, have been at the mercy of humans all along – available for exploitation, to be harnessed for a multitude of needs. The economic and industrial ones have always taken precedence over the psychological and the spiritual.    

4. Post-war Quercus

Quercus witnesses both the world wars, which impact his sylvan home in varied ways, and feels fortunate to be growing old in peace. He silently watches oaks, birches, beeches and pines around him being felled using advanced chainsaws, to be processed into end-use products in the technosphere, the  dynamism of  silviculture, the emergence of landowner associations and forest management societies, and national laws related to conservation of nature. He takes delight in a welcome improvement in the biodiversity of his forest,  with a return of bird species like the woodpecker and the owl, typical to old and tall trees, as well as bats and a host of saproxylic organisms. Quercus, however, also senses that the air he is exposed to, is increasingly getting polluted with undesirable constituents from activities in the anthroposphere, and the soil in the forest is getting acidified and thereby inhospitable to the much-needed decomposers producing humus.  He lives through devastating cyclones at the turn of the 20^th century and toughs it out during the droughts, epidemics, floods and heat waves [the symptoms of climate change which the world has been experiencing of late] which hit later, while observing changes in the composition of the fauna occasioned by alterations in the physiognomy of the forest. Tillon observes that each tree in the ever-adaptable forest increases the likelihood of survival of the whole. He wonders if biomimicry [‘arboromimicry’, more specifically] can inspire humankind to unite and help each other to overcome challenges, in the spirit of the trees of the forest.      

Make it O(a)K for Mother Nature

Tillon alludes, off and on, to the intrinsic value of Quercus the oak, and by extension, of all the arboreal landscapes on Terra Firma, which cannot be expressed in monetary terms [as ecological economists often try to do]. This reviewer also intends to add at this juncture that not just the flora but also the fauna of the forest possess immense intrinsic value.] Being an Oak is a product of the vivid imagination of a nature-loving ecologist, who recreates the life of an oak tree by blending scientific theory with story-telling,  ecology/botany with history. All the ‘what may possibly have happened’ in the story is compellingly convincing. After reading this book, your sincerely is much more convinced that trees are ‘personalities’ in themselves. Being an English-speaker not conversant in French, it behoves me to mention that translator Jessica Moore’s rendition in English deserves great acclaim.

Acknowledgement

This review is dedicated to the fond memory of my wife Varshita, who found strength and peace by spending time in forests, on river-banks, and by the lakes and fjords, in Norway and Sweden.