Drori doesn't get hung up on matters of definition: With a few provisos, the broad definition of a tree is a plant that has a tall, woody stem; it can support itself and lasts from year to year. Botanists debate about how tall such a plant must be. I've decided not to be too precious about this. The most important fact about them is shared with other plants: The world's trees are astonishingly diverse - we now know that there are at least 60,000 distinct species. Unable to run away from animals that would love to eat them, they manufacture unpleasant chemicals as a deterrant. They exude gum, resin and latex in order to swamp, poison and immobilize insects and other attackers, and to exclude fungi and bacteria. (9)
Eventually we learn that trees, like all other forms of life, in fact have symbiotic relationships with many other species (mycorrhiza are introduced with the fifth tree, the Silver Birch), but this isn't Drori's starting point. Trees are agents, as we learn, protective, manipulative and sometimes even aggressive. But as interesting to Drori is the way that trees' gums, resins, latex and other defensive traits are put to all manner of unintended uses by us humans.
Serendipity is important in Drori's framing. His first two trees - London Plane and Leyland Cypress - are both hybrids, and hybrids of recent vintage. Both seem to have happened accidentally in British gardens, which brought together trees from widely different places. (It's not part of Drori's brief to foreground the Columbian exchange or empire.) In the first case it's the American sycamore and Oriental plane, hybridizing perhaps three centuries ago. In the second, it's two North American trees - yellow cedar from Oregon and Monterrey cypress from California - meeting as expats in Wales. This happened not much more than three decades ago, but they're already the most widely ordered plant for British gardens. (They're perfect for privacy-protecting hedges.)
There's plenty to wonder at in the trees we learn about, but Drori nowhere muses, as strangler fig prophet Mike Shanahan did, that trees elicit experiences of awe, gratitude and reverence. That people develop "superstitions" around trees is a curiosity. Instead, there's always stuff going on. Trees are used by human beings for food and shelter and medicine, for nets and clothes and ship's masts, teas and tonics and poisons, canoes and charcoal and violins. In all these cases (except perhaps eating), we're putting trees' tricks to our own uses.
If there's a moral to Drori's story, it's about the meeting of arboreal and human ingenuity, just that we are liable to make too much of a good thing, felling vast forests without a thought for the morrow. That human beings didn't use to do that - and may have learned it through the omnicidal ethos of colonialism and the scale-destroying logic of capitalism - isn't part of the story but needs to be! (I suppose the thought of going around the world in 80 whatevers may be part of the problem.) For most of human history, humans beings lived with trees - Kimmerer would say human people lived with tree people - caring and being cared for.
In a time where our indebtedness to trees is obscure and abstract (in part because that derivate tree product plastic has replaced so much), we need to be reminded that our relationships with them are material, not just spiritual, involving giving and taking, not just beholding. This book might help me get this across to students in "Religion of Trees." We have always been involved with trees, not just surrounded by them. But I'd want to go one step further, suggesting that relationship is in a deep way preceded by symbiosis. Trees, most of them vastly older than we are (unlike those hybrids), developed in all their astonishing diversity always bundled with symbiotic species of other kinds, eventually welcoming us to join the feast.
