Book: The Age of Wood by Roland Ennos

I love wood, as did my dad. After all – he was a carpenter. Wood is pliable, easy to join, and easy to shape into anything you want. It looks and feels nice, and it literally grows on trees.

In the past, however, it was not only the “posh organic” material of choice; it was the only game in town if you wanted to create something – like, for example, our whole civilization.

Ennos challenges the common focus on stone tools in early human history. Wooden tools were far more prevalent and effective for many tasks – wooden spears, for instance, were as effective as stone-tipped ones in hunting experiments.

He suspects that the significance of wooden tools is underestimated simply because they did not survive to the present day.

Wood as the Backbone of Human History

Roland Ennos highlights wood’s pivotal role in human development, beginning with early hominins who transitioned from life in trees to life on the ground. Wood enabled humans to adapt to new environments, build shelters, and create tools. Its flexibility, strength, and flammability made it essential for survival and innovation.

1. When we were apes, we lived on trees to avoid predators
2. Wood is the perfect material for tools. Toolmaking is how we grew our brains
3. Wood is fuel for the fire. It sheltered us from predators and increased the calories we could absorb from food
4. Wood made our shelters, which in turn allowed us to lose fur, thus lose parasites so we could live in close quarters.
5. Wood made the Bow and Arrow which allowed us to hunt more effectively
6. Wood made coal which was essential to create steel, and fuel the industrial revolution

Structure of the Book

• Wood as an overlooked yet central material in human history.
• Unique physical traits that make wood indispensable.
• The transformative role of wood in human evolution.
• How wood influenced key historical events and technological advancements.

My Highlights

• Even by the sixteenth century, Britain had been forced to obtain almost all its masts from the countries adjoining the Baltic Sea.
• 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.
• Considering its historical importance, it is astonishing that the Great Mast Crisis is not better known. All schoolchildren are taught about the Boston Tea Party, even in Britain; none are taught about the Pine Tree Riot.
• It became clear to me that wood has actually played a central role in our history. It 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.
• Recent studies of the history of the global environment have shown that the key to understanding why hominins came down from the trees is climate change. Over the last 20 million years, the world’s climate has been getting cooler, caused in large part by movement of the earth’s tectonic plates. As India has plowed into the Eurasian plate, it has forced the Himalayas upward, and the silicate rocks this exposed have absorbed carbon dioxide from the atmosphere, reducing the strength of the greenhouse effect. The climate has cooled, and the tropics and subtropics have become more seasonal, with wet seasons being interspersed with increasingly long dry seasons.
• 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!
• They could have sharpened the points of their digging sticks while they were still green, using either their teeth or sharp stones, and used them later when they had dried out and stiffened up. A fully dried stick would be able to dig a hole around 50 percent deeper than a green stick.
• 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.
• An early hominin that could cook its food would be better able to survive, reproduce earlier, and build up a higher population size. With faster, more efficient digestion, it would not need so large a gut and could divert the energy to produce and maintain a larger brain.
• The jury is still out, therefore, about when humans first used fire. But whatever the exact timing, what comes out most strikingly from modern research on early humans is that the key to becoming terrestrial was to make use of wood, and in particular to exploit two of its fortuitously useful properties. In the first stage of becoming terrestrial, early hominins would have made use of wood’s becoming stiffer as it dries out, to fashion and use digging sticks to obtain their new source of food: underground storage organs. In the second stage, early members of our own genus Homo would have made use of the flammability of dry wood to make fires that could protect them from predators.
• 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 thermoregulating 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, ironically missing the opening “warm-up” match. 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 of Northern Europe. Presumably the disadvantage of losing the shielding effect of head hair is so great that baldness is strongly selected against.
• 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.
• 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.
• It was therefore because early hominins were sleeping inside wooden huts that they could afford to lose their body hair. And this would in turn have made us even.
• 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.
• 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.
• Many anthropologists have carried out experimental investigations comparing the killing performance of stone-tipped and simple wooden spears. The experiments, carried out on the corpses of pigs or on ballistic gel, must have been great fun to perform. However, though 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.
• I used this fact to safely investigate how the effectiveness of atlatls depended on their length. My master’s student Hannah Taylor filmed how far her family and friends could throw balls of different weights using an adjustable dog-ball thrower.
• But of all the ways of improving the killing performance of wooden projectiles, the best is the bow and arrow.
• …sharp wedges needed more energy to split the wood than thick, broad ones, and for a good reason. Most of the energy to split the wood was needed to overcome the friction between the wedge and the wood, and since thinner blades contacted the wood nearer to the tip of the crack, they had to push outward with a greater force to keep the crack moving forward, causing more friction. Thicker, broader blades needed less energy because they prized open the crack farther from its tip and needed a much lower force.
• Clay minerals consist of plates of mica that in their natural state are bound together with relatively weak hydrogen bonds; these are strengthened or weakened by removing or adding water. However, if the clay is heated to over 900°F, all the water bound up in the structure is driven off, and permanent bonds form between the clay particles. The clay is converted to a biscuitlike solid—earthenware—that is unaffected by water, but is still somewhat porous and weak. It has to be heated to over 1,800°F for some of the chemicals to fuse or vitrify to form a glasslike material that joins the clay particles together and makes a new material—stoneware—that is stronger and impermeable to water
• Because charcoal is made of the highly reactive element carbon, if they used it to burn metal oxides, it did not merely heat them up, but also removed the oxygen from the ore to produce pure metal.
• …art nouveau architect and designer Charles Rennie Mackintosh with their ladder backs.
• Wood also varies in color, principally because trees differ in the amounts of colored defense chemicals—tannins, phenolics, and the like—that they pump into their heartwood to kill fungal diseases and prevent rotting. The longer lived a tree and the warmer the climate in which it grows, the more defense chemicals it needs and hence the darker the wood. Of the temperate trees the long-lived oaks..
• The heights of carving in this tradition were reached in the work of two fifteenth-century German sculptors, Tilman Riemenschneider and Veit Stoss. Their elaborately carved altarpieces, some of which can still be seen in churches in Germany and Poland, are comparable in humanity and ambition to the better-known stone masterpieces of the Italian Renaissance. They are particularly successful in bringing to life the suffering of Christ and his followers.
• Despite extensive research no one has found the secret of the beautiful tone of Stradivarius violins. However, investigations of the wood have revealed that the soundboard is made from particularly slow-growing and fine-grained spruce that was harvested from the Alps. The fine grain of the wood and the bright tone of these instruments may be related to the cold weather and poor growing conditions of the Little Ice Age of the sixteenth to eighteenth centuries during which the trees were growing. With global warming, which speeds up tree growth, it may never again be possible to construct such perfect instruments.
• Baekeland found that he could overcome this problem by mixing the resin with wood flour to make a fiber-reinforced material; unwittingly he had copied the strengthening arrangement used in the cell walls of wood itself. The process was a success, and Baekeland found that he could produce plastic components of all shapes and sizes. The objects that were made in this new material, Bakelite, included a wide variety of new technologically advanced products: radios, telephones, and the like, whose rounded, fluid design had a great influence on the streamlined aesthetics of the art deco period.
• Infectious diseases such as measles, influenza, and syphilis that were brought in by the Europeans decimated the indigenous people. From a population of as high as 60 million people, it is thought that only around 6 million were left by 1600, a phenomenon known as the Great Dying. The result of this depopulation was that the cultivated fields of Mexico, the terraces of the Inca highlands, and the forest gardens of the Caribbean and Amazonia all reverted to forest, an effect that reduced global atmospheric carbon levels by around 9 Gtons. This would have lowered the CO2 concentration by around 3.5 ppm, enough to explain two-thirds of the global cooling of 0.27°F that was seen for the next two hundred years. The poor harvests of Europe in the seventeenth and eighteenth centuries that led to so much civil strife, and eventually to the French Revolution, were caused by the regrowth of forests thousands of miles away

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