Size Matters

Small things are difficult to see. The smallest things are difficult even to imagine. We are missing life at its smallest, overlooking living things that came before us and make us possible. We need to look inside the box more appreciatively.

OPEN this terrific graphic from the Genetic Science Learning Center at the University of Utah for a trip into the world of small. Click on the slider, slide it to the right, and zoom in past a sesame seed, past a skin cell, then a blood cell,  a bacterium, all the way down to viruses, molecules, and finally a carbon atom. It’s a wild trip. 

The zoom takes you down into the roots of life. It also takes you back in time. Back billions of years, from complex single-celled creatures and building blocks towards the not–alive viruses that may predate full reproductive life, back to one of the atoms that makes it all possible. Small came first. And life stayed small for a long time.

Then it got bigger. Humans are not only complex but relatively large. Elephants, whales, and trees grow larger than we do, but hundreds of species of everything from dogs to Humans are not only complex but also relatively large. Elephants, whales and trees grow larger than we do, but hundreds of species, from cows to ordinary bushes, come in our size range. Up to a point and with exceptions, a bigger body survives longer.

Perhaps this trend underlies our perceptions of authority and even spirituality. The entities that we worship in any sense of that word are bigger than we are—not only gods but powerful people who seem ‘larger than life,’ or the universe itself, or Nature. They are the somethings–larger than we are often seeking. We grant even big trees and elephants a majesty that we don’t attribute to bushes and mice. Large things, if we think they are friendly, offer inclusion and protection.


But we don’t usually feel that warm about tiny things. That’s partly because we simply can’t see them. I wonder what it would be like if we were able to see individual bacteria, skin cells, the cells in a piece of fruit in the same way that we can easily see even individual blades of grass. Imagine seeing the single–celled creatures floating in the air and in the water and on our skin, on other skins, in our food, in our rooms. Would we feel enveloped by life in the way that we do when walking in a forest or watching flocks of birds? If we could see all those individual cells pumping, crawling, swimming, dividing, could we find our something–larger in those somethings–smaller?

Peter Wohlleben’s “The Hidden Life of Trees”

Until recently I was quite sure that a broad difference between animals and plants was that animals, because they are mobile, readily interact with each other (flocking, pursuing, etc.) while plants, anchored to the ground, don’t do so because they can’t. Except to attract insect pollinators, plants, I thought, live a life of exquisite solo struggle, seeking only the sun and water.

I’ve been steadily learning how far off I was. German forester Peter Wohlleben’s popular book, The Hidden Life of Trees: What They Feel, How They Communicate, is the most compelling lesson yet.

Among his many descriptions of communication and mutual assistance is Wohlleben’s account of how trees defend not only themselves but also each other. Observers have noted, for example, that umbrella thorn acacias in the African savannah pumped toxins into their leaves when they felt giraffes nibbling on them. “The giraffes got the message and moved on to other trees in the vicinity. But did they move on to trees close by? No, for the time being, they walked right by a few trees and resumed their meal only when they had moved about 100 yards away.” They passed by the nearest trees because the trees being nibbled, in addition to pumping a repellent, “gave off a warning gas that signaled to neighboring trees that a crisis was at hand.” The giraffes knew these trees would not taste any better and kept walking.

hidden life of trees (pri.org)

pre.org

Many trees also have the ability to call in the air force. Reacting to bites from hostile insects, such trees emit scents that attract predators that devour the pests. “For example, elms and pines call on small parasite wasps that lay their eggs inside leaf-eating caterpillars.” The growing larvae devour the caterpillars from the inside.

The book brims with information and appreciations of this kind. Three more examples:

  • Trees that spend their lives in the forest fare much better than trees raised in one place and then transplanted to the forest. “Because their roots are irreparably damaged,…they seem almost incapable of networking with one another.” Like “street kids,” they “behave like loners and suffer from their isolation.”
  • Time for trees is slow and long. Internally, they, like animals, send alerts to parts of their body via chemicals and electrical impulses. But in a tree the electrical impulses move only about a third of an inch per second. (In our bodies, pain signals move  through our nerves about two feet per second, muscle impulses a hundred times faster.) No wonder it seems to us that plants are unresponsive.
  • Conifers (evergreens) “keep all their green finery on their branches” throughout the winter and have been doing so for 270 million years. Then deciduous (leaf-bearing) trees came along 100 million years ago, growing and discarding annually millions of delicate green solar panels. Was this an improvement? Why go to all that trouble? Wohlleben asks. Because “By discarding their leaves, they avoid a critical force—winter storms.” Between high winds, muddy soil, and a surface area equivalent to that of a large sailboat, tall evergreens take a battering in European winters. Growing and then dropping their huge surface area every year proved well worth while for the leafy new comers.

Wohlleben’s liberal use of human descriptors to explain the actions of trees delights many readers and annoys others. Andrea Wulf, in her review of the book, has both reactions.

I’m usually not keen on anthropomorphizing nature—and here trees are “nursing their babies” and having “a long, leisurely breakfast in the sun” while…fungus mushrooms are “rascals” who steal sugar and nutrients. These cutesy expressions make me cringe….But I have to admit that Wohlleben pulls it off—most of the time—because he sticks with scientific research and has a knack for making complex biology simple and thoroughly enjoyable.

I agree. While the vocabulary may bestow on trees a dignity and affection that we usually reserve for our own kind, it is scientists’ growing understanding of trees that creates the real story here. At a time of rapid environmental change, the book is as fascinating a revelation as one could ask for that life is even more intricate and purposeful than we knew.