## Metadata - Author: [[David George Haskell]] - Full Title: The Forest Unseen - Category: #books ## Highlights - Taoist union. Farmer’s dependence. Alexandrian pillage. Relationships in the mandala come in multifarious, blended hues. The line between bandit and honest citizen is not as easily drawn as it first seems. Indeed, evolution has drawn no line. All life melds plunder and solidarity. Parasitic brigands are nourished by cooperative mitochondria within. Algae suffuse emerald from ancient bacteria and surrender inside gray fungal walls. Even the chemical ground of life, DNA, is a maypole of color, a Gordian knot of relationships. ([Location 195](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=195)) - If Kepler could visit us today he would perhaps be pleased by our solution to the puzzle of the snowflake’s beauty. His insights into the arrangement of pomegranate seeds and honeybee cells were on the right track. The geometry of stacked spheres is the ultimate cause of the snowflake’s shape. But because Kepler knew nothing of the atomic basis of the material world, he could not imagine the minute oxygen atoms from which ice’s geometry grows. However, in a roundabout way, Kepler contributed to the solution to the problem. His musings on the snowflake prompted other mathematicians to investigate the geometry of packed spheres, and these studies contributed to the development of our modern understanding of atoms. Kepler’s essay is now regarded as one of the foundations of modern atomism, a worldview that Kepler himself explicitly rejected when he told a colleague that he could not go ad atomos et vacua, “to the atoms and the void.” Kepler’s insights helped others to see what he could not. ([Location 235](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=235)) - The relationship between the size of animals and the rate of heat loss has produced geographic trends in body sizes. When an animal species exists over a large area, the individuals in the north are usually larger than those in the south. This is known as Bergmann’s rule, after the nineteenth-century anatomist who first described the relationship. ([Location 261](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=261)) - Each down feather is made from thousands of thin protein strands. These tiny hairs combine to make a lightweight fuzz that holds heat ten times better than the same thickness of coffee-cup Styrofoam. In the winter, birds increase by fifty percent the number of feathers on their bodies, adding insulative power to their plumage. On cold days, muscles at the base of the feathers tense, puffing the bird and doubling the thickness of the insulation. ([Location 271](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=271)) - Slabs of flight muscle in the chickadees’ chests are the primary sources of heat. Flight muscles account for about a quarter of a bird’s body weight, so shivering produces great surges of hot blood. Humans have no comparably huge muscles in our bodies, so our experiences of shivering are weak in comparison. ([Location 281](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=281)) - Human bodies normally keep themselves at about thirty-seven degrees Celsius. If the body temperature drops just a few degrees, to thirty-four, mental confusion sets in. At thirty degrees, organs start to shut down. In cold winds like today’s, these few degrees of temperature loss can take place in just an hour of naked exposure. ([Location 289](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=289)) - The energy used by chickadees has been measured both in the laboratory and in free-living birds. On a winter day, the birds need up to sixty-five thousand joules of energy to keep themselves alive. Half this energy is used to shiver. These abstract measures become more understandable when they are converted into the currency of bird food. A spider the size of a comma on this page contains just one joule. A spider that fits within a capitalized letter holds one hundred joules. A word-sized beetle has two hundred and fifty joules. An oily sunflower seed has more than one thousand joules, but the mandala’s birds have no seed-filled bird feeder. Chickadees must daily find hundreds of food morsels to meet their energy budget. ([Location 299](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=299)) - Chickadees can coax sustenance out of the seemingly barren forest in part because of their outstanding eyesight. The retinas at the back of the chickadees’ eyes are lined with receptors that are two times more densely packed than are mine. ([Location 305](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=305)) - Chickadee eyes also perceive more colors than mine can. I view the mandala with eyes that are equipped with three types of color receptor, giving me three primary colors and four main combinations of primary colors. Chickadees have an extra color receptor that detects ultraviolet light. This gives chickadees four primary colors and eleven main combinations, expanding the range of color vision beyond what humans can experience or even imagine. Bird color receptors are also equipped with tinted oil droplets that act as light filters, allowing only a narrow range of colors to stimulate each receptor. This increases the precision of color vision. We lack these filters, so even within the range of light visible to humans, birds are better able to discriminate subtle differences in color. ([Location 311](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=311)) - The visual abilities of birds and mammals differ because of events in the Jurassic, one hundred and fifty million years ago. At that time, the lineage that gave rise to modern birds split from the rest of the reptiles. These ancient birds inherited the four color receptors of their reptilian ancestors. Mammals also evolved from reptiles, splitting away earlier than the birds. But, unlike birds, our protomammal ancestors spent the Jurassic as nocturnal shrewlike creatures. Natural selection’s shortsighted utilitarianism had no use for sumptuous color in these night-dwelling animals. Two of the four color receptors that the mammals’ ancestors bequeathed to them were lost. To this day, most mammals have just two color receptors. Some primates, including those that gave rise to humans, later evolved a third. ([Location 320](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=320)) - The birds spend as much time upside down, peering under twigs, as they do upright. ([Location 328](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=328)) - The degree of fatness varies among individual birds. Chickadees feed in socially stratified flocks, usually composed of a dominant pair and several subordinates. Dominant birds get access to whatever food the flock finds, so they generally eat well whatever the weather. These high-ranking birds have trim bodies. Subordinate chickadees bear the brunt of winter’s hardship, eating well only intermittently. The low-status birds, often youngsters or failed breeders, compensate for the variability of their food intake by getting fatter, buying insurance against lean times. But there is a cost to chickadee fatness. Rotund birds are easier prey for hawks. The fatness of each chickadee is a balance between the risk of starvation and the risk of predation. ([Location 334](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=334)) - The chickadees’ adaptations to the cold are remarkable, but they are not always adequate. There will be fewer chickadees in the forest tomorrow. Winter’s chill hands will pull down many of these birds, dragging them deeper than the appalling emptiness I felt when I experienced the cold. Only half the chickadees that fed among the falling autumn leaves will live to see the oak buds open in the spring. ([Location 357](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=357)) - Deaths on winter nights check the chickadee population, trimming any birds that exceed the scant supply of winter food. Carolina chickadees each require, on average, three or more hectares of forest to sustain themselves. ([Location 361](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=361)) - When summer arrives, the mandala will be able to support many more birds. But because the abundance of resident species like chickadees is kept low by winter’s meager supplies, the food available in summer vastly exceeds the resident birds’ appetites. This great seasonal flush of food creates an opportunity that is exploited by migrant birds that risk long flights from Central and South America to feed on the excess in forests throughout North America. Winter’s cold is therefore responsible for the annual migration of millions of tanagers, warblers, and vireos. ([Location 364](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=364)) - Plant physiology can generally cope with mere chilling. Unlike the chemical reactions that sustain humans, plant biochemistry can run at many different temperatures, and it does not fail when cooled. But when cooling turns to freezing, problems start. Expanding ice crystals will puncture, tear, and destroy the delicate inner architecture of cells. Plants in winter must swallow tens of thousands of blades, keeping each one away from their fragile hearts. Plants start their preparations several weeks ahead of the first freezes. They move DNA and other delicate structures to the centers of their cells, then wrap them in cushioning. The cells get fattier, and the chemical bonds in these fats change shape to make them fluid in cold temperatures. The membranes around cells become leaky and flexible. The transformed cells are padded and limber, able to absorb ice’s violence without harm. ([Location 402](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=402)) - Cells not only change their physical structure but soak themselves in sugars, lowering the freezing point like salt scattered on icy roads. Sugaring happens only inside the cells, leaving water around the cells unsweetened. This asymmetry allows plants to exploit an expected gift from the laws of physics: heat is released when ice forms. Cells surrounded by freezing water receive a temperature boost of several degrees. During the first frosts of winter, the sugared insides of cells are protected by the unsugared water surrounding them. Farmers exploit this burst of warmth by misting their crops on frosty nights, adding another layer of heat-releasing water. ([Location 411](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=411)) - Once all the water between cells has frozen solid, no more heat is released. But water inside cells is still liquid. This liquid oozes out of the leaky membrane around the cell. As the water leaks out, it leaves behind the sugars, which, being large molecules, cannot pass through the membrane. This process gradually draws water out of the cell as temperatures drop, increasing the inner concentration of sugars and further dropping the freezing point. When temperatures are very low, cells pucker into balls of syrup, unfrozen repositories of life, surrounded by shards of ice. ([Location 415](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=415)) - Most microbes in the rumen cannot live in the presence of oxygen. They are descendants of ancient creatures that evolved in a very different atmosphere. Only when photosynthesis was invented, about two and a half billion years ago, did oxygen become part of earth’s air and, because oxygen is a dangerous, reactive chemical, this poisoning of the planet wiped out many creatures and forced others into hiding. These oxygen-haters live to this day in lake bottoms, in swamps, and deep in the soil, eking out an existence in oxygen-free environments. Other creatures adapted to the new pollutant and, using an elegant sidestepping maneuver, turned the toxic oxygen to their advantage. Thus was born respiration using oxygen, an energy-liberating biochemical trick that we have inherited. Our lives therefore depend on an ancient form of pollution. ([Location 456](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=456)) - Giant cats and wolves need giant herds of food. The only places in the world that sustain large populations of carnivores are well endowed with browsers. After all, carnivore flesh is just plant matter passed up the food web. So, abundant fossil evidence of large predators is strong evidence for heavy browse on plants. ([Location 569](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=569)) - The second myth is that amphibians are “primitive” and therefore don’t care for their young. This latter fallacy is embedded in theories about the evolution of the brain claiming that “higher” functions such as parental care are confined to “higher” animals such as mammals and birds. The mother’s careful vigil shows that parental solicitude is more widely spread in the animal kingdom than hierarchical brain scientists suppose. Indeed, many amphibians care for their eggs or their young, as do fish, reptiles, bees, beetles, and a menagerie of doting “primitive” parents. ([Location 687](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=687)) - Salamanders are the sharks of the leaf litter, cruising the waters and devouring smaller invertebrate animals. Evolution has discarded Plethodon’s lungs to make its mouth a more effective snare. By eliminating the windpipe and breathing through its skin, the salamander frees its maw to wrestle prey without pause for breath. ([Location 693](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=693)) - The soil’s food web reaches its zenith in the shrew. Only owls will eat shrews; everything else gives them a wide berth, fearing their vicious teeth or the acrid taste of their scent glands. There is kinship with humans here. The first mammals were shrewlike creatures terrorizing the snails and centipedes of the Mesozoic. Our ancestors were shrill and vicious, leading a caffeinated existence in dark corridors. An analogy with our current state of being is tempting. Thankfully we’ve lost the poison fangs and pungent glands. ([Location 875](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=875)) - Stripping the mountainside of trees turns the forest soil from a moist duff to an oven-baked brick. Ground-nesting bees, wet-backed salamanders, and the creeping stems of ephemerals dry up and die in the parched soil. Only when the forest has regained its leaf litter, canopy, and dead wood do the creatures start to return, but this revival is slow, constrained by the lack of old dead logs to act as nurseries and by the sluggish dispersal abilities of flowers and salamanders. ([Location 956](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=956)) - Why should we leash our accelerating desire for wood and paper for the sake of saving a springtime explosion of forest biodiversity? Can’t the flowers look after themselves? After all, disturbance is natural. The old “balance of nature” cliché went out of fashion decades ago. Now the forest is a “dynamic system,” constantly assaulted by wind, fire, and humans, always in motion. Indeed, we can turn the question on its head and ask whether we need to go out and do some clear-cutting, to replace the fires that used to clear large areas of forest but have been suppressed by land managers for nearly a hundred years now. These questions are the roots of a thorny growth of arguments that choke academic conferences, government reports, and newspaper editorials. Does the forest need the buzz of chainsaws, or does it need time to renew itself unperturbed by log hunters? We are tempted to use nature as a model, but nature provides a Baskin-Robbins of justifications. Which flavor of forest life cycle would you like: the annihilating force of an ice age; or an ancient, undisturbed mountainside; or the dancing mischief of a summer tornado? Nature, as usual, is not providing the answer. Rather, we are thrown back a moral question: what part of nature do we wish to emulate? Do we aspire to the uncompromising, all-controlling weight of an ice sheet, imposing our glacial beauty on the land, retreating every hundredth millennium to free the forests’ slow regeneration? Or do we seek to live like fire and wind, cutting swaths with our machines, then moving on for a while, hitting at random intervals, at random locations? How much wood do we need? How much do we desire? These are questions of time and of magnitude. We can cut every two decades, or we can cut every two centuries; we can focus our extractive desires, or we can let them run across the whole; we can strip the forest bare, or we can remove just a few trees. Our collective answer to this question grows out of the values of millions of landowners, pruned and guided by society’s two clumsy hands, the economy and government policy. The forest is shattered like a broken windshield by surveyors’ lines, so the diversity of these values plays out in a mosaic across the continent. Despite this chaos, patterns emerge from the aggregate. We are neither an ice age nor a windstorm but something altogether new. We have changed the forest on the scale of an ice age, but at a pace accelerated a thousandfold. ([Location 959](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=959)) - In the nineteenth century we stripped more trees from the land than the ice age accomplished in one hundred thousand years. We hacked the forest down with axes and… ([Location 977](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=977)) - Cheap oil and expensive technology have now brought us to the second phase of our relationship with the forest. No longer do we cut by hand and haul with animals or steam; gasoline engines do it all,… ([Location 980](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=980)) - Human sweat is made from blood with all the large molecules removed, like soup passed through a sieve. The blood fluid passes out of our vessels, seeping around the spaces between our cells and into the coiled tubes at the bottom of sweat ducts. As the fluid passes up the sweat ducts the body pumps sodium back into its cells, reclaiming the valuable mineral. The faster the sweat moves, the less time the body has to recapture the sodium, so when we pour with sweat there is little difference between the mineral mixture in our sweat and that in our blood. We are literally sweating blood, minus the lumps. When the sweat moves out of us sluggishly, we produce fluid that has less sodium and proportionally more potassium, a mineral that the body expends little effort on reabsorbing. ([Location 1163](https://readwise.io/to_kindle?action=open&asin=B005GSYZB6&location=1163))