Preface. This is a book review, mainly with excerpts, of Ennos’s book “The Age of Wood. Our Most Useful Material and the Construction of Civilization”. If you know anything about woodworking, you will enjoy the detailed descriptions of how and why wood is so versatile and how various objects are made with wood, from wheels to cathedrals.

Wood was essential towards the evolution of us becoming homo sapiens, not just for fires, but all kinds of tools and weapons, that archeologists ignore  in favor of stone and metal since wood objects composted long ago. Even today, wood is essential in our fossil-fueled world.   And in the past, many wooden inventions transformed civilizations, wooden wheels, ships for war and trade, musical instruments, myriad tools, furniture, and barrels, which were the equivalent of tin cans, plastic bottles, and shipping containers today.

My book, Life after fossil fuels explains why we will return to the age of wood as our energy source and infrastructure, which all civilizations before fossil fuels was based on.  If I’d read it before publication, some of the material in it would have been cited in my book.  And if you are trying to preserve knowledge for our postcarbon future, this would be a good one to have on the shelf.

Alice Friedemann   www.energyskeptic.com  author of “Life After Fossil Fuels: A Reality Check on Alternative Energy”, 2021, Springer; “When Trucks Stop Running: Energy and the Future of Transportation”, 2015, Springer, Barriers to Making Algal Biofuels, and “Crunch! Whole Grain Artisan Chips and Crackers”. Podcasts: Collapse Chronicles, Derrick Jensen, Practical Prepping, KunstlerCast 253, KunstlerCast278, Peak Prosperity , XX2 report

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Ennos R (2021) The Age of Wood: Our Most Useful Material and the Construction of Civilization.

Wood and Human Evolution

For so long history and the story of humanity have been defined by stone, bronze, and iron, it’s time to recognize the equally important role wood played, and still does.

Anthropologists wax lyrical about the developments of stone tools, and the intellectual and motor skills needed to shape them, while brushing aside the importance of the digging sticks, spears, and bows and arrows with which early humans actually obtained their food. Archaeologists downplay the role wood fires played in enabling modern humans to cook their food and smelt metals. Technologists ignore the way in which new metal tools facilitated better woodworking to develop the groundbreaking new technologies of wheels and plank ships. And architectural historians ignore the crucial role of wood in roofing medieval cathedrals, insulating country houses, and underpinning whole cities.

Wood is the one material that has provided continuity in our long evolutionary and cultural story, from apes moving about the forest, through spear-throwing hunter-gatherers and ax-wielding farmers to roof-building carpenters and paper-reading scholars. The foundations of our relationship with wood lie in its remarkable properties. As an all-round structural material, it is unmatched. It is lighter than water, yet weight for weight is as stiff, strong, and tough as steel and can resist both being stretched and compressed. It is easy to shape, as it readily splits along the grain, and is soft enough to carve, especially when green. It can be found in pieces large enough to hold up houses, yet can be cut up into tools as small as a toothpick. It can last for centuries if it is kept permanently dry or wet, yet it can also be burned to keep us warm, to cook our food, and drive a wide range of industrial processes. With all these advantages, the central role of wood in the human story was not just explicable, but inevitable.

The key to getting a better grip on a smooth surface is not to use a hard material such as a claw, but a soft one, such as skin.  We could cover our finger pads with a biological rubber such as elastin, but this would wear away too fast. The solution evolved by primates is more ingenious: we use a soft internal fluid within our finger pads and surround it by a stiffer lining—producing a structure rather like a partially deflated car tire. Beneath the tips of our fingers are pads of fat, which deform easily to allow a large surface area of the more rigid surrounding skin to make contact.

This arrangement gives us an excellent grip on hard surfaces such as glass, ten times as good as that of hard hooves or claws—explaining why we remain sure-footed on smooth concrete and tiles, whereas horses are prone to slip in their stables, and panicking dogs often scrabble about on the kitchen floor. Also we have ridges known as fingerprints. On smooth materials such as glass, this makes our grip worse, since it reduces the area of contact, just as grooved tires in racing cars have poorer grip in the dry than slicks. However, fingerprints do give some important advantages. They can improve our grip in the wet (just like grooved tires) since they can channel away the surface film of water, and also on rough surfaces, such as branches, since the ridges interlock with ones in the bark. And the skin ridges where our touch receptors are located can magnify strains and so improve the sensitivity of our fingers. Finally, the alternation of strong ridges with flexible troughs in the skin allow it to deform smoothly when we grip an object, preventing blistering.

Primatologists are learning that the reason monkeys increased in size as they evolved was related to changes in their diets. Bush babies and their relatives the lorises are insectivores; they eat insects and other invertebrates, which are hard to find, hard to catch, and rather small. Insects provide enough energy to support a bush baby. However, a larger creature would be no better at finding, catching, and eating insects, but the amount of energy it would have to expend moving about to do so would be much greater.  Other possibilities for primates include eating leaves or fruit

A leaf-eating primate has to eat huge quantities of young leaves and hold them for days in its stomach to detoxify and digest them; this limits its energy intake. Leaf-eating monkeys tend to be large, potbellied animals with a slow metabolism and limited intelligence—they cannot afford to develop a large brain, but then again, as leaves aren’t hard to find, they don’t need to!

Those primates that changed their diet to eat fruit rather than leaves also tended to get bigger because fruit is plentiful in rain forests and is full of energy. With so many different types of trees in tropical rain forests, each species is widely scattered through the forest. Moreover, because of the lack of seasonality, trees can fruit at any time. Trees that are in fruit are rare and hard to find.

So fruit-eating primates not only have to be able to spot when fruits are ripe, they also have to be able to remember where fruiting trees are located within the forest, and to predict when they are likely to fruit, so they can get to them before the fruit is eaten by other animals. Consequently fruit-eating animals have to hold a great deal of information in their heads, mapping the world in space and time. Field studies and experiments on captive fruit-eating primates have shown that they can remember the location of large numbers of fruiting trees and compute accurate routes to travel rapidly and economically to the next tree to ripen. So it is no surprise to find that fruit-eating primates such as macaques and spider monkeys have brains that are on average about 25% bigger than those of their leaf-eating cousins, the langurs and howler monkeys. This has enabled them to develop more sophisticated social behavior and live in more cohesive groups.

The intelligence of monkeys’ pales in comparison with that of our closest relatives, the great apes: orangutans, gorillas, chimpanzees, and bonobos, whose brains are twice as large relative to their body weight. Most primatologists believe the apes acquired their larger brains to help them communicate with and manipulate their peers.

An orangutan would probably be killed by a fall from the canopy that would scarcely harm a small monkey. It struck me then that the early apes might have also evolved larger brains to help them navigate safely around their perilous arboreal environment and allow them to plan and follow the best routes through the trees. To do this they would also have had to develop a self-image; they would have to realize that their body weight altered their mechanical world by bending down the branches that were supporting them. In other words, their intelligence had a physical basis, not a social one: a feeling for the mechanical properties of wood.   Many years later I was surprised and pleased to learn that my idea was now a bona fide theory of the evolution of intelligence in apes—the “clambering hypothesis” of Daniel Povinelli and John Cant. Since the publication of their hypothesis in 1995, other field-workers have built up evidence that orangutans, in particular, do have a high level of understanding of the mechanics of trees.

Understanding the mechanics of tree branches gives the great apes another advantage: they can use them to construct a nest in which they can safely sleep. All the great apes are capable of making themselves complex cup-shaped nests in the tree canopy, while monkeys sit on as thick a branch as they can find, resting their weight on pads of skin that develop on their buttocks, but even so they repeatedly wake up throughout the night. An ape, sleeping within a broad, cup-shaped nest, is far safer and can sleep for longer periods and more deeply.

This is reflected in the neural activity in sleeping monkeys and sleeping apes. The apes have more frequent bouts of both NREM (non–rapid eye movement) and REM (rapid eye movement) sleep. These types of sleep are important in reordering and fixing memories, which can in turn help improve cognitive ability. Building nests could have helped apes get even cleverer.

It might seem to be a simple task to construct a nest, and that certainly appears to be what primatologists have thought, as they have given them scant attention. But it is not just a matter of breaking a few branches off and weaving them together. It is nearly impossible to snap a living branch off a tree by bending it. And this is not because the branches are too strong, but because the structure of wood affects how it breaks.

Wood is eight to ten times stronger longitudinally than transversely, and most types of wood are also 20–50% stronger in the radial direction than in the tangential. This pattern matches the forces the wood has to withstand. The high strength and stiffness of wood along the grain enables it to withstand the bending forces to which tree trunks and branches are subjected by gravity and the wind.  This structural arrangement also makes it almost impossible to detach a living branch. If you bend a branch of green wood, what you are doing is stretching the wood on the convex side, and compressing the wood on the concave side. In a typical branch the wood will fail first in tension, and the branch will start to break across, like a carrot or stick of celery. But it won’t break all the way. As the crack reaches the center of the branch, it gets diverted, traveling up and down the weak center line of the branch,

An orangutan would find a good strong horizontal branch to rest on, then construct its nest around this support. First, it would lean out and with one hand draw thick branches in toward itself, breaking them in greenstick fracture and hinging them inward, before finally weaving the branches together. The result was a cup-shaped elliptical nest around four feet long and two and a half feet wide. Sitting in the completed structure, the ape would reach out to grab thinner branches and, holding them in two hands, first break them in greenstick fracture, then twist them to break the two ends apart. It then stuffed the broken branches, complete with twigs and leaves, into the nest, behind and around itself to produce a mattress and a pillow, and finally on its lap to produce a blanket. The whole process was remarkably rapid. In Julia’s film, the male ape took only five minutes to build his nest, and half of that time was spent resting between the two stages.  It takes young orangutans years of observing their mothers and practicing by themselves for them to perfect their constructions. And orangutans are the only other great ape that walks more or less upright and with straight legs like us.

Our ancestors gained their ability to walk bipedally when they still lived in the trees. Moreover, it is becoming clear that far from striding out immediately into the plains, our ancestors remained in well-wooded regions and stayed in the canopy long after they had become able to walk upright. We have already seen that orangutans frequently walk upright along narrow branches, and that when they do so, they also cling to higher branches with their hands. As an animal puts its foot down, the branch moves downward under its weight, storing energy, before springing up again and returning that energy. The orangutan could therefore bounce along the branch almost effortlessly, like a person walking on a trampoline.  By holding on to branches could help an animal overcome another major difficulty of evolving bipedalism: keeping its balance.

It seems that it was only with the emergence of Homo erectus, less than 2 million years ago, that humans became fully adapted to a terrestrial lifestyle. What previously was continuous tropical and monsoon forest has opened up, the trees unable to cope with the longer dry seasons except in the damper soils along river valleys. Clearly, this change in vegetation was bad news for forest-dwelling apes.  They would have been forced to the forest floor, first of all to travel between the scattered trees, but also in search of other types of food to supplement their diet of fruit, such as eating the termites that abound in savannas, raiding honey from bees’ nests, and hunting small mammals such as bush babies. Like the chimps, they probably fashioned wooden tools, such as probes, chisels, and spears to do this, and maybe used stone hammers to break open the hard nuts and seeds that the new types of drought-tolerant plants produced. But their main source of food in the dry season, like modern-day hunter-gatherers such as the Hadza people of Tanzania, who live in similar savanna woodland, would have been underground roots and bulbs.

Roots are strongly defended. First, plants protect them mechanically, by incorporating tough fibers within them. Both the early australopiths and Homo habilis developed their dentition to cope with these mechanical defenses. Later australopiths, such as Paranthropus boisei and Paranthropus robustus, also developed large sagittal crests on the top of their heads, rather like ones you can see on modern hyenas, which acted as the insertion points of huge jaw muscles. It is thought that this would have helped them grind up the tough roots and crack open hard nuts and seeds.

Plants also defend their underground storage organs chemically, by incorporating astringent chemicals to precipitate out digestive enzymes, and toxins to poison consumers. Australopiths developed large guts to help digest this difficult food. They must have been potbellied, just like proboscis monkeys. But the main difficulty in eating roots is accessing this subsoil resource in the first place. Baboons, the only primates that currently live on the African plains, use their hands to dig in the soil, but they can only reach shallow bulbs and corms. Warthogs use their impressive tusks to dig a bit deeper. The hominins would have had to develop a new technology to access even longer, deeper roots.

The digging sticks used by modern-day hunter-gatherers, such as the women of the Hadza tribe, are even larger and more sophisticated. They cut sticks that are over a yard in length, an inch and a half thick, and weigh anything from one to two pounds. Their favorite ekwa hasa roots are around four feet long and highly nutritious. The Hadza women dig them up by pounding the pointed end of their sticks into the soil to break it up and levering out the loosened soil with a digging motion; the process is so efficient that the women can collect enough roots in a few hours for the daily needs of their band.

There must have been strong selection pressure in early hominins to learn how to break off and prepare thicker, longer, and stronger sticks. This may have driven them to develop new stone tools with sharp edges that could saw through wooden branches and whittle the ends into points. To do this, and to handle the digging sticks effectively, they would also have had to evolve stronger gripping hands with fully opposable thumbs.  Its strength, stiffness, and toughness is down to the molecular structure of the cell walls themselves. The cell walls are stiffened by crystalline microfibrils of cellulose, which are embedded in a softer matrix of hemicellulose that is stabilized by a polymer called lignin.  When the cell wall finally breaks, the fibrils uncoil like a stretched spring, creating a rough fracture surface with thousands of tiny hairlike fibrils projecting out of the wood. This process absorbs huge amounts of energy, making wood around a hundred times as tough as fiberglass, and giving wood its resistance to fracture. It’s the reason why trees stand up so well to hurricanes that can destroy more rigid man-made structures, and why wooden boats are far more resistant to bumps than fiberglass ones.

But the early hominins would also have been helped by the first of two incredibly fortuitous properties of wood, properties that are of no actual benefit to the trees that make it. If wood is broken off a tree and starts to dry out, its mechanical properties improve! This is most unusual for biological materials; bones, horn, and nails all get weaker and more brittle as they desiccate. At the 60% relative humidity of the savanna dry season, the water content of wood typically drops from 30% to 12% and its stiffness triples. Early hominins would have made use of this transformation – a fully dried stick would be able to dig a hole around 50% deeper than a green stick.

It seems puzzling that they continued to return to the trees; there must have been a major problem that prevented them from coming down permanently. Looking at the present-day African plains, it is clear what that problem must have been: they would have been extremely vulnerable to being eaten by predators such as saber-toothed cats, scimitar-toothed cats, and the ancestors of present-day lions and hyenas.  Baboons are the only large primates that live on the plains of Africa, and they have real problems with predation. Compared to early hominins, they are physically far better able to defend themselves; they have huge canine teeth, and a fully grown male may weigh as much as ninety pounds, more than a match for many large cats. Even so, baboons have to live together in groups of 20 to 200 individuals to protect one another, and yet they still get a rotten night’s rest. Even when they are living in zoos, baboons wake up 18 times a night, only sleep for 60% of their rest period, and get into deep REM sleep only around 10% of the time. This contrasts with 18% of the time for chimpanzees, which sleep in nests, and 22% for modern humans.

The only plausible way that our ancestors could have protected themselves on the ground at night from predators was by using fire. This is where the second of wood’s fortuitous properties comes in: it is flammable, especially when dry, and when it is burned, it releases a large amount of heat and light. The flammability of wood is of no use to trees; it’s just another fortunate accident that it does burn, though most living trees, especially ones growing in rain forests, are extremely resistant to being set alight.

The cell walls of living wood contain a lot of water, around 30% of their dry weight, and the cell lumens in the sapwood around the outside of the trunk and branches are filled with water; a tree trunk can therefore contain three times its dry weight of loose water. Before wood can burn, all this water has to be heated up and evaporated off, which requires as much as a third of the energy that is released when the wood finally burns. Cell wall material is chemically stable, even at temperatures above 212°F; the lignin keeps the cellulose fibers rigidly bound together, which explains why we can’t cook wood and make it into a useful food by boiling it!

Starting fires without matches or firelighters is no easy business. The usual methods employed by modern hunter-gatherers are either to generate heat by rubbing sticks together, or to make sparks by striking flints against each other. It is unlikely that early hominins would have been able to do either.

Predators such as cheetahs and birds of prey are drawn to bush fires, feeding on the small mammals and birds that are flushed out in a panic by the flames. Savanna chimpanzees are also attracted to fires, gathering the cooked seeds of bean trees and eating them. From following and using naturally occurring fires it is a small step to keeping those fires alight.  They simply carry smoldering logs with them as they travel about the bush, lighting fires when they need them. And from keeping fire alight in smoldering logs, it is only another small step to keep a fire burning at a permanent camp, and building it up at night to repel predators.

Setting up a permanent camp, and being able to sit together around the campfire, would have had other advantages. It would help to keep the hominins warmer during the cool nights typical of savanna regions. The light from the fire would also help lengthen the time when individuals could carry out tasks such as making and mending tools. There would also be opportunities for a greater variety of social interactions: sharing food and exchanging information. Having a permanent fire would help speed up the evolution of both practical and social skills.

The advantages of cooking are perhaps best shown by what happens to those human health fanatics who eat only raw food. Even if they grind up their food carefully before eating it, raw foodists have problems in digesting what they eat and invariably lose weight and conditioning. Typical weight loss is around forty-four pounds for men and fifty-five pounds for women.

The Naked Ape & the sweating hypothesis

Hairlessness is an extremely unusual trait for terrestrial mammals: only the naked mole rat comes to mind.  A newly hairless hominin would have had to produce more melanin to absorb the harmful ultraviolet rays, turning its skin black.  It has been at least 1.2 million years since hominins lost their hair in our ancestor Homo erectus

But what drove hair loss? The generally accepted explanation among anthropologists is that losing hair allowed early humans to keep cool in the hot savanna regions into which they had moved (and it still is the main hypothesis). So effective is heat removal by sweating that anthropologists have gone on to suggest that losing our hair was crucial for another advance in the evolution of humans: the ability to hunt large animals.

But it is not certain that it is hairlessness that gives the San Bushmen the advantage; two other mammalian predators also hunt in this way in savannas, African hunting dogs and spotted hyenas, and both of them are covered all over with hair like the prey they hunt. In fact, endurance hunting is rare in hunter-gatherer societies, maybe because it has the disadvantage that though the hunter can keep cool by sweating, by doing so he loses large amounts of water.

The hunting hypothesis suggests that early men could run farther and for longer in the heat of the day than prey animals because sweating would keep them cooler for longer. If they tracked their prey for long enough, their prey would eventually overheat and become immobilized. But wait, that’s a problem, for example,  US army recruits have been known to lose over four quarts of water per hour when exercising in the desert. The resulting dehydration can be fatal if weight losses exceed 2% of body weight. Nowadays hunters can carry water bottles with them to keep up their fluid levels, but there is no guarantee that early humans had invented vessels that were capable of carrying water.

The sweating hypothesis has a more fundamental problem, one rarely mentioned by anthropologists. In the heat of the day a naked body would actually absorb more heat than one covered in hair, meaning it would need to be more actively cooled. You might think that this would only occur when the air temperature exceeds our body temperature of 98.6°F, when heat would enter our bodies via convection. This only rarely happens in savannas, where the mean daytime maximum temperature is usually around 84°F. However, this leaves out the most important mode of heat transfer between our bodies and the environment: radiation. On a hot sunny day a hairless human body will absorb long-wave radiation emitted from the hot ground, and even more important, the much larger amount of short-wave radiation (mostly light) that comes from the sun. On such a day the net radiation entering our bodies can amount to around 670 watts per square yard, much more than the amount of energy we ourselves generate. The layers of hair follicles on a hairy animal will shield it from practically all of this radiation, so while the surface of its pelt might be hot, its skin remains at body temperature. For this reason, most savanna mammals are hairier than their cousins that live in dense forest and tend to have particularly dense hair on their upper flanks to ward off the sun’s rays. Protected by their heavy fur coats, they have to use far less water to keep themselves cool than naked humans.

In deserts the problems of keeping cool in the daytime are most acute. It is noteworthy, then, that those “ships of the desert,” the camels, have particularly heavy coats of hair on their upper flanks, while their human riders cover themselves with loose flowing robes. The shielding effect of hair also helps explain why humans have maintained a dense covering of hair on the tops of our heads; it helps us keep our most vital organ—our brains—cool.

The importance of hair in thermo-regulating our brain was driven home to many English cricket supporters back in 1994, when the English all-rounder Chris Lewis shaved his head at the start of a tour of the West Indies. He promptly went down with sunstroke So important is our head hair in keeping our brains cool that the human races that inhabit hotter parts of the world, such as Native Americans and Africans, have lower rates of male-pattern baldness than the Caucasian inhabitants of the cool regions

And you may have spotted another problematical aspect of the hunter hypothesis: its inbuilt sexism. The researchers who have investigated this theory (almost all men) have concentrated on an activity, hunting, that they have assumed was also carried out entirely by men. They totally ignored the contribution of women, who, they assume, spent much of their time “gathering” or perhaps simply waiting for the men to bring home their catch. They do not explain how hairlessness would have helped the women dig up roots, make fires, or cook. Indeed, according to the theory, women should actually be hairier than men since they would not have had such great cooling demands on their metabolism, whereas the reverse is true.

Several scientists have championed an alternative hypothesis, one that was first put forward in 1874 by the naturalist Thomas Belt, and one that applies to both sexes: that humans lost their hair to reduce their ectoparasite load. The reasoning is that hair loss occurred because early humans were now living and sleeping together in semipermanent camps, rather than in solitary nests.

Ectoparasites would therefore be more likely to build up around the camp and become more of a problem. It is certainly true that before the advent of modern insecticides, we were highly troubled by such parasites. Our mattresses were infested by bedbugs, our head hair by lice, and pubic hair by crab lice. Moreover, humans are the only one of the 193 species of monkeys and apes to have its own species of flea, Pulex irritans, something that is only possible because we live in permanent settlements; the larvae fall to the floor and live on organic debris in our houses, guaranteed to find new humans to bite once they have emerged from their pupae as adults.

Ectoparasites are not only irritating and suck our blood; they also carry dangerous infectious diseases such as typhus, various forms of spotted fever, and bubonic plague. There would therefore have been strong selection pressure on any morphological feature in early humans that would have reduced the ectoparasites’ numbers. The ectoparasite theory suggests that the best way to do this was to lose our body hair. in World War I it was found that cutting soldiers’ hair shorter greatly reduced the buildup of head lice.

Reducing the length and thickness of our hair not only makes it easier to visually spot fleas and lice on our skin; recent research by Isabelle Dean and Michael Siva-Jothy of the University of Sheffield, England, has also shown that our fine body hairs act as excellent movement detectors, allowing us to feel where the parasites are. Finally, the theory also provides a satisfying explanation of why women are less hairy than men: staying longer at camp than the men, they may have been more prone to being loaded with parasites.

Whichever hypothesis you favor, the benefits would have had to be large enough to overcome a serious disadvantage of nakedness. Naked Homo erectus individuals would have suffered from a quite different thermoregulatory problem than overheating during the day: they would have been extremely prone to getting cold at night.

All warm-blooded animals have a range of air temperatures at which they are comfortable and at which they can keep their core body temperature constant without having to raise their resting metabolism. Within these temperatures they can regulate their body heat merely by changing their behavior—by curling up, for instance, or stretching out. As you might expect from what I have outlined above, our upper critical temperature is quite low, around 97°F, even in deep shade, and our lower critical temperature is high, around 77°F. We could be comfortable living naked in a rain forest, therefore, where air temperatures range around 82°F–90°F (and rain forest tribes consequently tend to wear few clothes), but not elsewhere.

At night in the Serengeti it can effectively feel more like 43°F–50°F; tourists to the region are advised to bring sweaters and jackets for the cool evenings. A naked Homo erectus living 1.2 million years ago on the open plains of East Africa would therefore have got cold at night and have had disturbed sleep. There are three possible ways out of this conundrum

Early humans could have huddled around the fires that they built and maintained overnight for protection from predators. Most of us have sat around campfires sometime in our youth, and they certainly warm the side that faces the fire. However, the side of our bodies that faces away from the fire and the top of our shoulders, which face the sky, can get cold. Out in the open our bodies also lose heat rapidly to the cold ground.

Another way they could have kept warm is to have used animal skins as bedclothes. However, it is difficult to believe that physical evolution could have been moving one way—making people colder—while behavioral evolution at the same time had to try to make up for it. Besides, the first actual physical evidence for clothes, or the tools such as needles needed to make them, comes far later in the story of humans—scraped hide 300,000 years ago, and sewn clothes just 20,000 years ago.

It is far more likely that the Homo erectus were already doing something that would help keep them warm at night before they lost their hair; at their campsites they were already building shelters that helped protect them from the rain, shelters that would also have helped keep them warm. They would certainly have a good incentive to do this in the rainy season. None of the great apes like getting wet; Sumatran orangutans, for instance, often make second nests directly above their sleeping nests and use them as canopies to keep off the rain. For early humans, long used to building sleeping nests on which they rested, it would not have been a problem to construct simple huts to shelter themselves. Indeed, many tribes of hunter-gatherers still build small semipermanent huts from thin branches that they cut off savanna trees; they insert the thick ends of the branches into a ring of postholes in the ground and fasten them together at the top in the same way that apes weave their nests together. The frames are then covered with leaves or skins or even coated in mud.  The huts of modern hunter-gatherers fall apart within a few weeks or months of being abandoned and leave no trace.

You might think that flimsy wooden huts would provide little warmth, since cold air could rapidly penetrate such a drafty structure, but they can be quite effective, and anything that shields us from the cold night sky helps.  Even sleeping under trees provides more warmth, one reason the hunter-gatherers of the Hadza tribe of Tanzania still sleep beneath trees during the dry season. Largely because the huts cut down air currents and shielded them from the cold night sky, sleeping inside a hut would feel 8°F–10°F warmer than outside, enough to allow for a comfortable night’s sleep.

Because early hominins were sleeping inside wooden huts they could afford to lose their body hair. And this would in turn have made us even more dependent on our practical woodworking skills, to make fires and build ever-more-elaborate shelters, and eventually to use other materials to make sheets and clothing. Paradoxically, as we got better at these activities, we would have started to be able to colonize cooler climates. Becoming hairless forced us to become more ingenious and to rely on our intelligence to help us manipulate our environment, rather than have to adapt to it as other animals do. It would have helped a fairly feeble primate conquer the world.

Stone & wood tools

The study of stone tools has dominated anthropology and archaeology ever since 1831, when the Danish antiquarian Christian Thomsen introduced the concept of classifying the “ages of man” according to their dominant materials—stone, bronze, and iron.  Archaeologists have spent huge amounts of time and effort classifying stone tools, arranging them in chronological order, replicating their manufacture and use, and following their development. In doing so, they cemented in place a worldview in which the lives of our early ancestors, and in particular their material culture, was dominated by their relationship with stone. It was generally assumed that early “Stone Age” men were the first to produce tools; that the first tools were made of stone; that stone tools dominated their world; and that the sophistication of early stone tools demonstrated the mental superiority of early humans.

Stone tools were the only human artifacts that appeared to have survived from the time of early hominins; anything made of organic materials—skin, plant fibers, or wood—had long since vanished. However, in the last 50 years new discoveries by primatologists and anthropologists mean that we now know that none of the assumptions made by nineteenth-century archaeologists are valid.

Apes produce a wide range of tools, so humans cannot be exalted over other animals because they were the first toolmakers. Most ape tools —spears, chisels, digging sticks, and nests—are made of wood, not stone, and it is highly likely that early hominins would have inherited their woodworking skills from the apes. So the first tools used by early hominins would have been made of wood, not stone. The reconstructions of the lives of early hominins that have been made by devotees of stone make it obvious that they used mainly wooden tools—to hunt animals, to dig up plant roots, and to construct shelters—and that they burned wood to keep off predators, keep themselves warm, and cook their food. If we cast our mind back to those dioramas in local museums, for instance, most of the tools they depict were actually made of wood. The men had wooden spears to kill game and used wooden poles to hang it from, and back at camp the women were standing beside wooden huts and cooking their food over wood fires. Stone tools were only used to butcher the animals that had already been killed and to scrape their hides to make skins.

Finally, the first stone tools were hardly sophisticated objects, particularly if we compare them with the artfully constructed nests of apes. The earliest ones, the Oldowan tools, which date from 3.2–2.5 million years ago, often resemble random pebbles, and even the flakes produced by the Acheulean technology, which emerged 2.2 million years ago, are pretty rough and ready. After all they were produced rapidly, simply by hammering two lumps of stone together, or by hitting a piece of stone with a bone or a log of wood. Hand axes, which were first produced around 2 million years ago, certainly look more impressive and show evidence for the first time of clear design. However, even hand axes can be made in as little as 20 minutes and are essentially just tear-shaped flakes of rock with two edges. Their design remained largely unchanged for hundreds of thousands of years, so their manufacture demonstrates little evidence of intellectual progress.

Only much later, with the sophisticated retouching techniques that were developed in the Upper Paleolithic period, around one hundred thousand years ago, did stone tools become sophisticated enough to impress any small child that we might have brought into the museum. Only then did humans shape blades that actually look like modern daggers, harpoons, and barbed arrowheads. So stone tools were by no means as novel or central to the life of early humans as has been assumed.

In any branch of learning, once a culture is established, it seems to be hard for those initiated into it to break free. Anthropologists have continued to this day to overemphasize the importance of stone tools and ignore those made from other materials.

The properties of stones result from their composition; they are made up of crystals or amorphous blocks of inorganic chemicals. In typical igneous rocks, such as granite and dolomite, these have solidified from a molten state, while in flint they have precipitated out from solution. Sedimentary rocks, such sandstones and shales, are composed of bits of igneous rock that have been pressed together, while chalk and limestone are made from the fossilized inorganic skeletons of dead organisms. The strong bonds between the atoms make stone extremely stiff and hard. This makes it ideal as an impact tool. If you use a stone to strike a nut or hit a piece of bone, it’s the nut or the bone that will deform more, and all the kinetic energy in the stone will be used to break them. None will be absorbed by the stone. However, if two stones are hit together, the energy has nowhere else to go, and cracks will readily run through or between the crystals, breaking one or both stones. Stone is brittle and breaks easily, and if there are no predetermined lines of weakness, as in flint, hitting the stones together in the right way can create fractures in a predicted direction, creating sharp edges. The hardness of stone makes these edges ideal for cutting; they can withstand the large compressive stresses set up as the sharp point is pressed into or slid across a softer material such as flesh or even bone and slice through it. This is why sharp flint tools are ideally suited to butchering animals and scraping skins.

The brittleness of stone has a major downside, though. It makes the material weak in tension, since small surface cracks can readily run through the whole stone; rods of stone, just like sticks of blackboard chalk, are easily snapped. Stone knives therefore need to be short and thick to prevent their blades from being loaded in tension, and even if a stone spear could be fashioned, it would be far too delicate to use; it would fall apart at its first throw.

In contrast, we have already seen that wood has evolved in trees to be strong in both compression and tension, and extremely tough along the grain, which is why tree trunks and branches are so good at resisting bending. Dried wooden branches have even better properties, being just as strong and tough as green wood, and three times as stiff. They are, therefore, ideal for making digging sticks and spears: they are rigid and strong in bending, so they don’t flex or break when subjected to bending force; they are tough enough to withstand impacts; and they are still hard enough to pierce skin or soil. They are also relatively easy to make; they can be shaped when the wood is green, when it is still soft enough to be cut, carved, and finished.

It’s thoroughly predictable, therefore, that most of the large tools that the early hominins used were made of wood and only the small cutting tools were made of stone. Their huts would essentially have been inverted versions of the nests built by their ape cousins, and their spears and digging sticks would have been similar to those created and used by savanna chimps. And there was probably little difference in the planning involved in producing wooden and stone tools. The tools that modern apes create are made for the moment and used immediately, either to sleep, dig, or hunt, and they are hardly modified at all from branches and twigs.

The increasing success of humans is best explained by their development of their wooden tools, particularly their weapons. The first real intellectual advance that hominins made must have occurred when our ancestors started to use stone tools not just to process their kills but to construct wooden tools. This would have had to happen when early hominins moved onto the savannas. They would have needed to make thicker digging sticks to get at roots and tubers in the dry season, and larger spears to hunt game bigger than bush babies. And they would have had to use larger branches to construct the huts in which they sheltered.

The first fully terrestrial hominin, Homo erectus, would not have been able to do this without using tools. With their small incisors, they would not have been able to sharpen their spears and digging sticks, and having less powerful arms than their arboreal ancestors, they would not have been able to break off big enough branches to make their shelters. They would have needed to use stone scrapers to sharpen the points of their tools, and to use stone knives, axes, or saws to cut off branches. Homo erectus would have had to become the world’s first carpenters. In doing so they would be the first primates to make a tool not just for immediate use, but to make another tool.

The chimp fashions every aspect of its spear where and when it will be used. It strips off the leaves and side branches of the branch with its hands and sharpens the thin end with its teeth. When hominins made a spear using a hand ax, their actual actions are not necessarily more complex, but the process did involve two separate sets of actions that could take place at different times and places: making a hand ax, and then using it to make the spear. The whole process therefore involved not only integrating information from the past, using so-called working memory, but also imagining future actions, using what has been called constructive memory.

Making the chimp’s spear involves 14 steps, which acted on three “foci,” the chimp itself, the prey item, and the tool. In contrast, the human spear took 29 steps, acting on eight foci. The complexity of the task had been more than doubled.  Early humans may have carried around hand axes that were made by someone else. The process might, therefore, also show evidence of greater social organization, not just better individual mental capacity, within Homo erectus.

We have found no actual wooden objects for the first million years following those first signs of woodworking, so we do not know what tools Homo erectus made. This has led many anthropologists to doubt the importance of wooden tools, and in particular to doubt the hunting capability of these early humans.  They often thought that hominins might until recently have been at best opportunistic scavengers, only able to rob the carcasses of large herbivores, maybe acting together with small stabbing spears to drive away other carnivores from the prize.

Only when humans colonized the cooler, wetter parts of the globe did conditions allow wooden tools to be preserved. One of the main reasons we have such a fine archaeological record of early humans in Europe is that the wet, acidic peat soils that accumulate in the colder regions protect organic materials such as wood from rotting and preserve them surprisingly intact.  The earliest recorded wooden tool is the Clacton Spear, 450,000 years old.

The sheer number of spears and corpses that have been found suggested that some sites must have been an ambush area; the early humans, who would have belonged either to the species Homo heidelbergensis or to our even closer relative Homo neanderthalensis, must have acted together in a group to cut off the horses between dry land and water before slaughtering them, though the horses had probably not all been killed at the same time. Altogether, the finds speak volumes of the sophistication of these early humans. They were not only capable of fine carving, of being able to imagine the shape of the spears within the trees and shape them with stone tools, but were also able to organize themselves into efficient hunting parties, to exploit the behavior of their prey animals, and kill them safely from a distance.

A major finding 1990 was that rather than relying on a sharp wooden point, Neanderthals and early Homo sapiens started to haft a sharp stone tool, rather like a hand ax, to the front of their spears, cutting a groove in the end to receive it, and holding the blade in place using a combination of animal glue and sinew binding. The manufacture of composite spears was therefore extremely complex, with several separate tasks or “modules”—preparing the rope; boiling up the glue; shaping the stone point; and cutting the groove in the handle—even before the final assembly. This shows even greater organizational and technical ability and intelligence on the part of the Neanderthals. I find it hard to imagine that I would be able to carry out such a complex task without lengthy training.

The experimenters were clearly expecting the stone-tipped spears to be better at penetrating flesh, they found little evidence of this. Both wood and stone are harder than skin, so they both cut through it with ease. In some studies, the wooden tips even penetrated farther than the stone ones, though there was some evidence that the wider stone blades could cause damage over a greater volume of flesh.

Composite spears have the disadvantage that the brittle stone tip is more prone to snapping off, so they would need mending more often. The real advantage may have been due to the higher density of the stone. The heavy tip of the spear would bring its center of gravity forward, enabling it to be thrown effectively, while it could also be held and used as a stabbing spear. Composite spears could therefore act both at close quarters and at a distance and be used as both offensive and defensive weapons.

But both wooden javelins and composite spears have a limited killing range. The shortness of our arms means that we need to contract our arm muscles much faster than at their optimal speed to move the hand holding the spear forward and upward. Furthermore, of all the energy used to accelerate our arms and hands, around half is wasted. This limits the speed we can impart to a hand-thrown object, so few people can throw spears of any type more than thirty yards. Fortunately, though, our ancestors developed several ways to overcome this problem and make themselves into more efficient hunters; and most of them did so using techniques that worked by artificially extending the length of their arms.

Early humans threw their javelins with the aid of leather thongs called amenta, which they looped over two fingers. It is also becoming clear that from around twenty-three thousand years ago Upper Paleolithic Homo sapiens did much the same, but using a special tool to hold the string. From the beginning of the twentieth century, archaeologists had been unearthing decorated rods of wood or antler into which a hole had been drilled toward the wider end.

In the past, wood craftsmen had many jobs, still seen in the last names from wood-based trades: the Carpenters, Wrights, Wainwrights (who made carts and wagons), Bodgers, Bowyers, Fletchers (arrows), Turners, Bowlers, Coopers, sawyers, Foresters, Colliers (charcoal), Masons, Millers, and Glaziers, Potters, and Smiths (charcoal to heat their furnaces).

Spears, Bows & Arrows

Even better results can be achieved to throw a spear farther and with greater accuracy by using a spear thrower. Also developed in the Upper Paleolithic and still used extensively in Central and South America (where they are called atlatls)

The spear thrower is a simple stick six to 18 inches long with a cup or hook at the far end. To use it, the thrower is held horizontally under the spear, its hook overlapping the back of the shaft, while the hand holds on to the shaft farther forward. The thrower acts as a third joint to the arm, the spear or dart being propelled forward by rotating the thrower forward with the wrist at the same time as the arm. The mechanics is identical to that of the modern dog-ball throwers

Yet another technique to increase the killing range of wooden tools was to use the stick itself as an extension to the arm and rotate it forward as it was thrown, like a person throwing a stick for a dog. This technique is fairly effective at increasing the speed of the stick when it is released, but as the stick tumbles through the air, it slows down far faster than a spear because of the increased aerodynamic drag. These problems were overcome, though, by the people who perfected this method, the Aborigines of Australia. They invented a wide range of boomerangs, all of which have a streamlined cross section to reduce drag and help them fly through the air.

Some (the less crooked ones) are designed to fly straight and can be lethal at up to 200 yards. But of all the ways of improving the killing performance of wooden projectiles, the best is the bow and arrow. This combination was probably first invented some 65,000 years ago in Africa, though evidence from Europe only seems to go back some 20,000 years. Rather than relying on the fast-twitch performance of our arm and shoulder muscles, bows make use of the larger forces and greater energy we can produce when these muscles contract slowly. As we pull back on the string, elastic energy is stored in the bow, which is subsequently released when we let go of the string, propelling the arrow forward.

Bows have three major advantages over all the other techniques we have seen. First, since our muscles can produce more energy when contracting slowly, a bow can release more energy to a projectile, so that arrows can be shot over nine hundred feet.

Second, since a bow is drawn with a slow, smooth movement, it can be aimed far better and is a far more accurate weapon than a spear. Finally, since from the front the archer barely seems to move, she or he is far less conspicuous to prey than a javelin thrower, so the bow and arrow makes a much better stealth weapon.

It takes 102 tasks, spread across 10 subassemblies, to make a complete bow and arrow set. The development of wooden weapons had made us an apex predator, allowing us to inflict a mass extinction on the world around us. Even before we had learned to modify our environment by farming it, we had used wooden tools to kill off mammoths and other magnificent beasts in Asia, North & South America, Australia and Europe.

Clearing forests

Only in the last 60 years have we realized how effective Neolithic polished axes could be at cutting wood and their vital role in our rise to civilization. They help cut down forests, farm, and build towns in wetter areas where burning them down wasn’t possible.  We developed polished stone axes when the climate changed 15,000 years ago to open small clearings in forests where fresh regrowth would attract game and to set up camps.  Sawing is only good for branches of an inch or less, while axes allowed us to cut down trees and build roomy houses out of beams and planks split from tree trunks.  Now we could build boats to venture farther away and trade with other peoples. The earliest boats were canoes dug out of a trunk, and log boats.

Agriculture

After forests could be cleared, crops could be grown.Farming depended on wooden tools as well, wooden digging sticks to plant seeds, spades to dig irrigation canals, and wooden buckets to pour water on crops.  Polished stone tools enabled them to build large homes, fence fields, make furniture, hoseware, boats, and tools.

Coppicing

After using logs and planks from tree trunks to build homes, people discovered coppicing woodlands, which could produce smaller manageable pieces of wood to build homes faster and easily. Many trees don’t die when cut down, but resprout shoots that can be harvested repeatedly (i.e. oak, ash, chestnut, hazel, willow).  After a while rods of consistent diameter and length will grow.  These shoots grow rapidly from the stump that already has a root system supplying the tree with water, and the water doesn’t have to be transported up a tall trunk.  They grow faster than tree branches and more wood per area of ground.  It’s great for firewood and eventually to produce charcoal.  Also since they grow so fast, the leaves are farther apart, making a straighter, stiffer, and stronger piece of wood than a branch.

Coppicing is incredibly energy efficient. In the 1650s, people in England and Wales obtained about 20 terajoules of heat energy a year burning firewood, just over the energy people and farm animals expended on their own metabolism. Burning wood produces about 7.3 megajoules per pound, so that meant about 1.2 million tons of firewood burned a year. A coppiced woodland can produce 2 tons of wood per acre, son only 600,000 acres, or 950 square miles of coppiced woodland, 1.6% of the surface area of England and Wales could produce this much wood.

Peat is another possible fuel, but was even more uneconomic to move and has only have the energy per kilogram as wood with 20% of its density, or 10% of the energy per unit volume. Despite that, the dutch got 25 petajoules of heat from peat, 3 times more energy per person than England, and removing peat exposed rich clay soils which were drained and converted to arable farmland. Peat also fired glassworks, potteries, brickworks, saltworks and more. By by 1700 the easy peat reserves were mostly exhausted.

But growing timber for all the non-fuel uses of wood takes a lot longer.  Forests can produce half as much wood a year, about one ton per acre.  Though still, that meant in 1650 1400 square miles of land, 4% of the land area could meet demand.  And in fact, forests covered about 10% of the land before the industrial revolution, so it would appear to not be a problem.

Wood Transport to cities & industries

But it was. The problem lay in how hard it was to cut and transport the wood to where it was needed.  It is very time-consuming to harvest, cut into usable pieces, and pack into a small space.  Coppiced firewood was cut into relatively straight twigs and bound into faggots 3 feet long with an 8 inch diameter, then put on wagons for transport.  If no rivers were involved, the poor states of roads made wheeled transport even more slow and expensive with exorbitant prices if carried more than a few miles.  So possible for villages and small towns, but impossible as larger towns and cities grew.

So in medieval Europe, larger cities could only exist at ports or on large navigable rivers.  In the largest city on the continent, Paris, the whole Seine River basis was adapted to allow the rafting of wood.  The same was trye on the Rhine where enormous rafts were floated. By the end of the 18^th century, Dutch rafts could be 400 yards long and 90 yards wide.

Any more wood for industries was impossible to provide, so industries lay well outside of cities, where the forests were.  Glassmakers used potash from burning beech trees, soap with potash and animal fats, gunpowder from alder wood charcoal.  And the largest industry, the ironworks, were located where there was both iron ore and forests, with the iron smelted from charcoal of oak, beech, and hazel.

Metal Smelting

Ironically, metals made people even more reliant wood and used far more of it to smelt metals.  We were already heating clay to waterproof it.  The first clay pots were found in East Asia about 10 to 20,000 years ago. With waterproof pots, we could store food and liquids, and cook food on fires. We also learned how to make bricks.  To make really good pots, bricks, smelt metal, and around 2300 BC glass, required charcoal, which created temperatures up to 1800 F.

Metal axes were far superior to the old polished stone axes, and allowed people to make precise joints such as the mortise and tenon, overlapping joints, and dovetails, allowing plank ships and wheels to be constructed.   Finally boats that had watertight joints could be created and ships made much larger and more stable.  The Roman Empire couldn’t have existed without the huge plank ships that transported wheat from Egypt to Rome.

Charcoal

Only at around 400°F does heat start to break the wood down. The huge polymer molecules—cellulose, hemicellulose, and lignin—start to split up and to form a wide range of smaller liquid molecules. This process, known to scientists as pyrolysis, releases energy, which for the first time starts to generate heat to drive the burning. As the temperature rises further from 400°F to 600°F, these small molecules evaporate, and some of them react with the oxygen in the air to produce a flame, generating further heat. Some of the gases escape, however, along with some carbon particles, and are released as smoke. Finally, when the breakdown of the cell wall has been completed, only carbon is left; the wood has been transformed into charcoal.

Unlike the volatile chemicals produced by pyrolysis, the carbon does not evaporate and only burns when the temperature reaches 900°F; it reacts with oxygen at its surface to produce carbon dioxide and energy. Since nothing evaporates from the charcoal, however, no flame is produced and there is no smoke, which is why the embers of a fire just glow red-hot.

Material life was much the same from the Iron Age until the industrial revolution

As you can see in museums and living history attractions, people depended heavily on wood. The homes were made of wood or had wood frames roofed with wooden shingles. The furniture was almost all made of wood – the beds, tables, chairs, cupboards, and kitchenware such as barrels, jugs, cups, bowls, and spoons. Their fuel were piles of logs to heat homes and cook food. Farm carts and wagons were wood as well as tool handles, plows, hay rakes, mattocks, and scythes. The Power plants: water mills and windmills, were nearly entirely made of wood.  Non-wood items such as iron cutting tools or iron pots and pans had been smelted with wood charcoal. Clothes spun on wooden spinning wheels, and leather tanned with tree bark. And wood was burned to make salt, brew beer, and more.

So of course the rich favored glass, pottery, and metal objects since commoners could not afford them. Despite not using as much wood, the enormous amount of wood it took to make the charcoal to make these finer items would have left the poor colder and less well sheltered.

Wood has many disadvantages that metals, plastics, and other technologies eventually replaced.  Wood isn’t great for complex three-dimensional items, it can’t be molded into a shape like clay or metal, and its hard to join pieces together.  Because it’s more weak and brittle across the grain than along it, wood is hard to carve and vulnerable to splitting.

Iron was better than copper or tin because it is far commoner and possible to mine and smelt locally.  It also had better mechanical properties and could be made into finer and harder-wearing cutting tools, especially bar iron.

What about stone homes?

The impermanence of wood led many cultures to attempt to build stone buildings.  But in the end, they weren’t watertight or large, and ended up housing the dead usually.  Though they can be made, especially round buildings.  Or using wood, but hiding it from view.  Which is why the Notre-Dame Cathedral in Paris burned so spectacularly, above the stone vault roof the actual roof consists of giant wooden trusses made of huge tree-trunk-size beams to hold the roof up.

Stone buildings are perfect for Italy where they stay cool on hot summer days.  But in Northern Europe the stone loses heat rapidly and once cold, take ages to heat up again.  This was somewhat overcome by hanging tapestries on the walls, and later wood paneling, since wood is a far better insulator of heat than stone, since it’s innumerable tiny air spaces restrict heat flow.  In fact, wood is 10 times better at stopping heat loss than wood.

Types of trees and their wood qualities

To withstand high winds, large broad-leaved canopy trees produce wood with large water-conducting vessels and fairly hollow fibers giving them a medium specific density of 0.5 (oak, ash, beech, pine, spruce, fir). Understory trees are shorter, need less water, and so are slower growing and longer lived, producing denser and harder timber (holly, dogwood). Fast growing pioneer trees that colonize open ground (birch, poplar, maple, aspen, willow) have wide vessels and thin walled fibers to enable rapid growth and a low specific density around 0.35.  Tropical rain forests have slow growing trees with a density of 1.0 (ebony and ironwood) so heavy they sink in the water.

Color: this varies a lot depending on the defensive chemicals used, such as tannins and phenolics to kill fungal diseases and prevent rot. The longer a tree lives, and the warmer the climate, the darker the wood from defensive chemicals.  So oaks and cedars have the darkest and most durable timber, and flimsier poplars and willows lighter wood.

Carpenters and green woodworkers use mostly medium-density wood from large canopy trees.  Caok and cedar for buildings, ships, and carts that might get wet, or ash and beech for tools and indoor furniture.

Wood for Ship’s Masts and American Independence

In Britain the problem of obtaining masts became acute. The country had a tree cover below 10%, and its forests had long before been put under management. Few conifers grew there, and no trees tall and straight enough to be made into ships’ masts. Even by the sixteenth century, Britain had been forced to obtain almost all its masts from the countries adjoining the Baltic Sea. The problem was that the fleets of its northern rivals, Holland and Sweden, were always threatening to cut off this supply, and in any case tall trees were becoming scarcer and more expensive.  And Australian gum trees were useless.

The old-growth forests of New England contained huge, straight-trunked eastern white pine trees in seemingly limitless numbers. From the mid-seventeenth century onward these trees, which could grow up to 230 feet tall with a diameter of over five feet, became the tree of choice for the British navy.

Unfortunately, in seeking to secure their supply of masts, the British government made a series of policy blunders that were to have disastrous consequences. They had difficulty buying tree trunks on the open market because the colonists preferred to saw them up for timber; this was after all a much easier way of processing them, considering their huge size, rather than hauling the unwieldy trunks for miles down to navigable rivers. The British could have bought up areas of forest and managed them themselves, but instead, in 1691 they implemented what was known as the King’s Broad Arrow policy. White pine trees above 24 inches in trunk diameter were marked with three strokes of a hatchet in the shape of an upward-pointing arrow and were deemed to be crown property.

Unfortunately, this policy soon proved to be wildly unpopular and totally unenforceable. Colonists continued to fell the huge trees and cut them into boards 23 inches wide or less, to dispose of the evidence. Indeed, wide floorboards became highly fashionable, as a mark of an independent spirit. The British responded by rewriting the protection act to prohibit the felling of all white pine trees over 12 inches in diameter. However, because trees were protected only if they were not “growing within any township or the bounds, lines and limits thereof,” the people of New Hampshire and Massachusetts promptly realigned their borders so that the provinces were divided almost entirely into townships.

Many rural colonists just ignored the rules, pleaded ignorance of them, or deliberately targeted the marked trees because of their obvious value. The surveyors general of His Majesty’s Woods, employing few men and needing to cover tens of thousands of square miles, were almost powerless to stop the depredations of the colonists, and the local authorities were unwilling to enforce an unpopular law. The situation reached a crisis in 1772, exactly when the Chemin de la Mâture was being completed, with the event known as the Pine Tree Riot.

News of the riot spread around New England and became a major inspiration for the much more famous Boston Tea Party in December 1773. The Pine Tree Flag even became a symbol of colonial resistance, being one of those used by the revolutionaries in the ensuing War of Independence. Designed by George Washington’s secretary Colonel Joseph Reed, it was flown atop the masts of the colonial warships.

The British were forced to use smaller trees from the Baltic for their masts, and had to clamp together several trunks with iron hoops to construct “made masts.” This arrangement was at best unsatisfactory, and many British ships spent most of the ensuing war out of action in port with broken masts. To make matters worse, the colonists started to sell their pines to the French, who had opportunistically sided with the rebels.

Without Britain’s usual naval superiority, America prevailed and became independent in 1783.

Woodcraft before coal started the Industrial age

Even the simplest of wood items took a long time to make with the hand tools of a carpenter. Time to cut to size, to make the joints with careful measurements, markings, and finally cutting and making animal glues not nearly as strong as today’s.  A door would take several days – selecting and cutting down trees, sawyers to cut into planks, and years of drying the wood out.  Even wealthy households had very little furniture like chairs, tables, or chests, expected to last for generations.

Wheels took several days, carts several weeks, and ships years to construct.

If a craftsman came up with an innovation, it wasn’t likely to spread to others.  Crafts were handed down through the generations.  Techniques were learned by watching over many years in apprenticeships, not from written instructions.  In many ways, following past traditions can maintain

high standards and mistakes avoided, but this limits innovation, especially since improvements were kept secret from outsiders or even within a guild.

A lack of scientific understanding of the properties of wood was especially a problem for ships, which for most of history let in quite a lot of water since the joints between planks weren’t waterproofed.  Finally in 1805 diagonal bracing was invented allowing ships to become much larger, sturdier, and waterproof, but soon after ships were mainly made from iron.

Coal begins the Industrial Revolution

Coal has 5 times more energy than wood and 50 times more than peat.  Great Britain had huge reserves of coal near ocean and river transport. Its use went from 150,000 tons a year in 1600 to 500,000 tons in 1700, enabling population to grow from 200,000 to 575,000.  The iron, glass, salt, and other industries far away in forests moved to London burning huge amounts of coal in addition to that used in homes to heat and cook with.

The Royal Society began publications of DIY manuals on smithing, joinery, bricklaying and more, allowing innovations to spread quickly.

To transport all the new goods being made, new canals were built.

For a while ironmaking was held back by limited amounts of wood charcoal, but then the kinks of using coal were figured out (explained in more detail in the book).  Iron pots, pans, fireplaces, and of course cannons – 14,000 of them were made to win wars.

America had so much wood that it wasn’t until 1850 that coal finally overtook wood charcoal in making iron.  Even the steam engines burned wood rather than coal almost until the 20^th century.

Chapter 12 Wood in the 19^th century

As mentioned earlier, timber is prone to splitting, difficult to join, flammable, and vulnerable to warping & rotting in the open air.  So you’d think that by the end of the 18^th century iron bridges and other infrastructure would have replaced wood, but cast iron is brittle and breaks when stretched from cracks. So it couldn’t be used for chains or beams that might be bend, or withstand impacts. As an material, it couldn’t replace wood, and was only safely used to replace masonry, in the pillars for instance.

It was wrought iron that changed everything. Bridges of record length, buildings of unprecedented size, and gigantic ships that were finally watertight and far more protected from cannon balls, able to destroy any wooden ship.  Wrought iron is 10 times stiffer than wood and up to 3 times as strong in tension, and 10 times as tough. It could also be made in large quantities and large pieces. And chains for a new type of bridge: the suspension bridge.  Railways hadn’t been able to use cast iron, but wrought iron was so successful that huge locomotives could be built with wrought iron boilers less likely to explode and wrought iron rails that could handle heavy trains. Greenhouses were built.

Wrought iron precision machinery could manufacture goods once made by hand, and overcome the difficulty of joining wood with metal joints, rods, and eventually nails.  Mines could go deeper as wrought-iron rods linking lattice works of timber.

By 1830 nails were already revolutionizing how homes were built and could be mass produced. Instead of logs cut into heavy beams, precision steel saws cut logs into thin planks and two0by-fours nailed together to make the light framing that allowed walls to be fully assembled on the ground and lifted into place and nailed.  On the outside the whole structure was sheathed in planks, and on the inside with boards, and insulation placed in between to keep the house warm in winter and cool in summer.

This enabled American settlers to be cheaply housed, and most Americans live in wood-framed homes today, further improved with the invention of the wrought-iron screw making houses, furniture, fencing and faster and cheaper to construct.

Books and newspapers benefited from cheap ways to turn wood pulp into paper. Today over 440 million tons of paper are made a year.

But coal and iron can’t hold a candle to the world that we know today, dependent on petroleum and its ability to make massive amounts of steel, plastic, and concrete (the making of which is described on pages 228-229).

Plastic was a miracle product because it could be poured into molds, while complex objects made of wood would take a considerable amount of time to carve. Some plastics are stronger than wood yet much lighter than iron or steel.

Plywood overcame the tendency of wood to split along the grain, plus could be bent and molded into two and even 3-dimensional curves. In the 1920s glued veneers solved the waterproofing problems in construction. Chipboard and fiberboards have their uses too.  And wood-laminate architecture is leading to the construction of wood high-rise buildings, such as an 18-story tower in Norway.  It weighs just a fifth as much as a conventional concrete-and-steel structure, use half as much energy to construct, and more resistant to fires than steel frames.

Wood is not obsolete – quite to opposite, 1.9 billion cubic yards were used in 2018, more than the 1.7 billion cubic yards of cement.

Plantation forestry

Monocultural stands of trees are especially vulnerable to wind damage, fungal diseases, and pests, which can destroy whole forests.  Not much can be done since trees have too long a life cycle to selectively breed to become resistant to diseases.  To work around this, exotic trees are often planted, like the Monterey pine, and it brings with it exotic pests and diseases that can kill native trees not adapted to cope with them.  To name a few: ash trees killed by ash borer beetles and fungus Chalara; chestnuts in America with chestnut blight from Japan, hundreds of species of tree are now threatened by Armillaria root rot around the globe killing everything from conifers to eucalyptus – indeed, only larches and birches appear to have any resistance.

Forests don’t fit into the short time and scale of the modern world.  It takes decades to grow trees.

And if the goal is being carbon neutral, forget it.  It takes fossil energy to harvest, transport, and machine trees.  The most energy-intensive step of all is kiln drying. The energy to evaporate water is 1 megajoule per pound (MG/lb), and newly felled wood has so much water that kiln drying makes up the lion’s share of all wood products, about 4.5 MJ/lb of dry wood.