The Tree: A Natural History of What Trees Are, How They Live, and Why They Matter – Colin Tudge, 2006

Read for Nature & Environment – we loved it! Tudge writes beautifully. I especially enjoyed the methodical tour through all the major plant families; the notion that trees are just as dynamic as animal organisms, just not on our timescale; and the clear explanation of polyploidy (first time I’ve felt like I’m beginning to understand it).

Short quotes

  • “an old kapok tree in Costa Rica in which biologists had thus far listed more than four thousand different species of creatures”
  • “A forest is a forest because it has trees in it, not because it may have sloths and toucans or squirrels or chimpanzees. The trees are the prime players and the animals are the dependents.”
  • “the idea … that each of us might aspire to be a connoisseur of nature, and connoisseurship implies a combination of knowledge on the one hand and love on the other, each enhancing the other.”
  • What is a tree? “Many plants … have independently essayed the form of the tree. Each achieves treedom in its own way. ‘Tree’ is not a distinct category, like ‘dog’ or ‘horse.’ It is just a way of being a plant.”
  • “The more that is revealed, the more wondrous nature becomes. The more we know about living creatures, the more deeply we can engage with them. This is the appetite, as Hamlet said, that grows from what it feeds on.”
  • “Typically, the botanist says that two similar trees are the same, while the mateiro [indigenous expert] says they are different” and is proved right.
  • “The Ducke Reserve is about a hundred thousand times smaller than the United States … yet harbors nearly twice as many kinds of native trees.”
  • “It is at least possible that many local names in Maori and a thousand other languages are not meant to express particular relationships at all. After all, traditional societies—or at least the specialists within them—typically know their local flora and fauna as well as the rest of us know our friends and family. When you know everyone individually, you do not need to name them in ways that express particular relationships.”
  • “The Latin names can be rather long, and sometimes too similar for comfort. If you’re sitting up late with a 40-watt bulb it’s easy to confuse, say, the Myrtaceae, Myricaceae, Myrsinaceae, and Myrsticaceae.”
  • “For my part, I feel that Darwin’s is a glorious vision. I love the notion that we are literally related to all other creatures: that apes are our sisters, and mushrooms are our cousins, and oak trees and monkey puzzles are our distant uncles and aunts. Conservation, on such a view, becomes a family affair.”
  • W. D. (Bill) Hamilton proposed that it was the need to avoid parasites that prompted the evolution of sex—for sex produces the generation-by-generation variation that makes life difficult for parasites, which tend to be highly specialized, to get a hold.”

Longer quotes

Groves of redwoods and beeches are often compared to the naves of great cathedrals: the silence; the green, filtered, numinous light. A single banyan, each with its multitude of trunks, is like a temple or a mosque—a living colonnade. But the metaphor should be the other way around. The cathedrals and mosques emulate the trees. The trees are innately holy.

I’ve been fascinated by lantana since seeing it grow wild in Tucson and recognizing it as the pretty pot plant with multicolored flowers I know from the northeast, so this was an interesting anecdote:

Dr. Sas Biswas, of the Forestry Research Institute in Dehra Dun, northern India, tells a charming story of sandalwood trees he once found growing in a dead straight row in the middle of nowhere. Why were they there? Who had planted them so carefully and then abandoned them? No one, is the answer. But in the past there had been a garden; and around the garden was a fence; and along the fence grew the inevitable Lantana; and sandalwood had grown as parasites from its roots. Now the garden and the fence are long gone and the Lantana with it, but the sandalwood remains.

Mangrove tree roots breathing:

The rising tide pushes the old air out; and when it recedes, fresh air flows in again through the lenticels and pneumatophores. Thus the roots of the mangrove trees effectively breathe. They use no muscle power to do this, as an animal must. The sea is their diaphragm. The tide serves to aerate their roots; wind and fleets of obliging animals spread their pollen and seeds. Trees just don’t need the elaborations of muscle and blood and nerves on which animals expend so much.

You would not immediately suspect, if you confronted an aspen in an urban park, that it is among nature’s most resourceful trees. It has a languid air, with wanly fluttering leaves on long, flat stalks, which in autumn turn a melancholic yellow. … Yet for all its bloodless foppishness the quaking aspen has the widest distribution of any North American tree, and in large stretches of the far north it is the dominant and at times the only species.

Fig pollination dependent on specific species of fig wasps:

If we do anything to interrupt the lives of the wasps—are too free with insecticide, for instance–then we we will kill off the figs, or at least ensure that the present generation is the last. The fruits of figs are essential provender not only for bats and birds but for a host of other creatures too. In Panama, figs of various kinds are in fruit all through the year, while most other fruits are far more seasonal. There are times when figs are all there is. Take away the figs, and half the fauna could be in serious trouble. The whole ecosystem balances on a pinpoint—and we could tip it into oblivion without thinking; or, indeed, we could let it slip through our fingers even if we were trying very hard to save it. On the other hand, precarious though it seems, figs and wasps have maintained their relationship in one form or another without interruption for more than forty million years. There is robustness in the system. If only we can work with it, it might pull through yet.

In this book I learned

  • Rainforest trees are especially difficult to identify and study because there are so many different species, most of them look alike, and they flower at unknown/unpredictable times.
  • “[Linneaus] led botanical expeditions from his native Uppsala with the local band out in front and everyone dressed in a uniform of his own design.” Wish I could find an illustration of them!
  • Bryophytes are not known to be a clade – “nobody knows the relationship between [liverworts, hornworts, and mosses], or whether they are closely related at all”
  • The Lost Gardens of Heligan
  • Northern conifers are tall and thin not to shed snow, but to maximize the light they get on the side, since the sun is low
  • Knobcone pine and Monterey pine can enclose their old cones in wood
  • Wollemia, like the coelacanth, was only known from 120 mya fossils until a group turned up in Australia in 1994
  • The name “spruce” comes from “Prussia”
  • Retrophyllum minus (a podocarp) is a tree that grows in running water!
  • Double fertilization – Tudge’s explanation is easier for me to understand than Wikipedia’s: in angiosperm embryogenesis, “a second cell in the pollen fuses with two sets of cells in the ovule to form a combined cell with three sets of chromosomes; and this peculiar triploid cell then multiplies to form a food store, rich in carbohydrates, protein, and often fat, that surrounds the embryo.”
  • Seagrasses are like marine mammals – they are land plants that moved to the water, but they still have flowers and pollen!
  • Avocados have a crazy system where there are two types of flower, A and B, that can only be pollinated by the opposite flower based on time of day
  • Macadamia nuts are indigenous to Australia – “the only native Australian food plants of significance to world markets”
  • Sweetgum, as the name indicates, has a fragrant resin. Tudge says it’s “known as storax or styrax,” but Wikipedia uses “storax balsam” to distinguish it from “storax” aka benzoin. I am fascinated by resins, and we have introduced sweetgums around here (Liquidambar styraciflua), but I’ve never noticed their resin. Something else to look out for!
  • There’s a native bittersweet, Celastrus scandens! I’ll keep an eye out – sounds like the terminal flower/berry clusters would be the easiest way to tell.
  • “Golden rice” is no big deal because other plants (mangos, papayas etc.) have plenty of vitamin A. “If high-tech vitamin A-rich rice is ever of help at all, it is only in regions where traditional agriculture has been shoved aside by high-tech, industrialized, monocultural farming.”
  • “a tree could grow to a height of nearly two miles if the tensile strength of water was the only constraint on its growth”
  • Sebertia acuminata accumulates nickel from soil
  • Parkia flowers: “pompoms of stamens and styles, bright red or pale yellow or bronze, depending on species, that hang from on high on long, thin threads like Christmas baubles”
  • Dependency of tambalacoque on the dodo’s gizzard apparently is too simplistic, as they are growing fine if protected from pigs etc. “Evidently it wasn’t the presence of dodoes they required but an absence of imported herbivores. This is excellent news for the tambalacoque. But it is a pity, indeed, to kill off such an excellent story.”

I questioned these

  • Tudge repeats a tidbit from the Encyclopedia of Wood, that the Paris Metro tracks are made from ekki timber (Lophira alta). I can’t find any independent confirmation, but the wood is used for railway sleepers.
  • He claims “beeches that are allowed to grow into forest trees shed their leaves” (as opposed to hedges). I certainly see tons of marcescent beeches in the woods – or are those not “forest trees” because they don’t get huge before disease takes them?

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