Introduction: Looking Back and Into the Future

Our objective in this book is to describe and discuss forests and their significance in our world. Human societies need the products of forests—not just wood and wood products but all the ecological goods and services that forests provide: biodiversity and its essential benefits, carbon sequestration and storage, stable water supplies, land protection, recreation. But relatively few people are aware of these services and benefits, so we hope to contribute to raising awareness of these values and the importance of forests, and to providing the science-based information needed to guide political action and decisions about them. Toward achieving these objectives we consider how forests grow and why different types occur in different parts of the earth; what constrains their growth, why they are important to us and how they should be managed.

Most people like trees. We plant and nurture them in our parks and gardens—in fact the very idea of a suburb suggests leafy, tree-lined streets—but there are big differences between trees in the suburbs or scattered around farmhouses or in small woodlots, and those in forests. Forests are embedded in our psyche: they have been important to us throughout our history, but most people, nowadays, know too little about their importance to the planet and to our lives and economies.

People of different cultures and backgrounds view forests in different ways: some see them as rather mysterious wilderness, others simply as blocks of land with commercial potential. Forests are basic to the folklore of people who have lived in and with them for generations. Scandinavian and German myths and legends tend to involve dark and sometimes forbidding forests. In some countries, access to the forests to camp, collect berries and mushrooms, hunt, or simply to walk in and enjoy them is a right entrenched in law.

In the modern world virtually all forests are exploited by humans in various ways, mostly, of course, for wood production for industrial purposes or for fuel. Some natural forests are protected and well managed but economic pressures are bringing about the destruction of many others. Tropical forests provide a living to—sadly, remnant—native peoples in Indonesia, Papua New Guinea, and the Amazon, but those forests are being destroyed at frightening rates by illegal logging or to establish oil palm plantations or cleared for crop production. Forests have been and, indeed, remain among the dominant vegetation types across the earth, but one of the most important processes by which humans have transformed the earth is through deforestation. In the following paragraphs we provide an outline of the history of human interaction with forests and a short synopsis of the history of deforestation around the world. In later chapters we consider some of the consequences and implications of destroying forests.

Forests in Human History

It's now generally accepted by anthropologists and archeologists that our species evolved in the forests of central Africa somewhere around 3.5 million years ago—less than 1 percent of the total age of our earth. Why those early ape-like creatures started to walk upright on two limbs instead of just going on the way they were, presumably swinging through the trees, is a matter of speculation. It seems inarguable that our very early ancestors moved from living in the central African forests to the savannah; the species called Homo sapiens emerged about half a million years ago and became essentially identical to modern humans about 50,000 years ago.

Much of the early development of human societies was in the area covered by modern Israel, Lebanon, Syria, Iraq, and eastern Iran, none of which was heavily forested. From there, early humans radiated west along the north coast of the Mediterranean Sea and east, within the warm subtropical latitudes. There is also archeological evidence of Homo erectus (not yet H. sapiens) activity in China more than a million years ago.

It's estimated that the human population of the earth has increased from a few hundred thousand at the time of the retreat of the glaciers, around 10,000 years ago, to about 200 million at the beginning of what we in the Western world call the Christian era. Of that 200 million, a significant proportion was in China. Morris (2010) says there is evidence that rice and millet were cultivated in the Yangtze valley between 8,000 and 9,000 years ago, and that 6,000 years ago the Yangtze and Yellow River valleys were mostly subtropical forest. Forests were cleared as the steady growth of human populations led to the expansion of cropland around more and more villages.

As the glaciers and ice sheets of the Ice Age retreated, forests expanded into huge areas where tree growth had previously been impossible. Human populations also increased as the ice retreated and people moved north into regions of Europe that had been uninhabitable. Human disturbance of forests in Europe seems to have become significant around 6,000 years ago—approximately the same time as in China—and increased from then on. There are written accounts from the ancient Mediterranean civilizations, notably Greece and Rome, of extensive forest clearing for wood for fuel, building, and shipbuilding, leading to denudation of the countryside. The damage was exacerbated by widespread overgrazing and browsing, particularly by goats. This led to soil loss by erosion and reduced agricultural productivity, which may well have been a significant contributor to the decline of those civilizations.

The Roman Empire at its peak, near the beginning of the Christian era, included about sixty million people; Rome itself reached about one million, a massive city population for the time. Wood was the most important building material and, throughout the empire, trees were cut for housing and the great shipbuilding program of the Romans, as well as to provide fuel for domestic heating, iron-working, and ceramics manufacture. The expansion of agriculture also resulted in increasing land clearance, so the Roman period saw considerable changes in forest cover, particularly in southern Europe. Clearance in Europe was checked by declining populations associated with the disintegration of the Roman Empire, the invasions by Huns and Goths from the east, constant war, the spread of various lethal diseases, and famine. Populations recovered and increased between the fourth and seventh centuries, with accelerated land clearance; by the end of the fourteenth century "farmers had plowed up vast tracts of what had once been forest, felling perhaps half the trees in western Europe" (Morris 2010, 367). The plagues known as the "black death" caused human populations to crash in the...