The Fragile forest

Human beings have a natural affinity with trees. The world's forests cradled our ancestors and nurtured them with nuts, berries and other wild fruit. Later, forests provided the fuel that warmed the cave dwellings of early man and then provided the materials with which he made weapons for hunting and defence, built huts, log cabins and stockades. Long before this, however, the tree, or at least its ancestors of the green plant kingdom, had actually created the conditions which made human life possible.

When the Earth condensed out of a cloud of interstellar gas and dust, some 4,600 million years ago, it was surrounded by a dense atmosphere of cosmic gases made up largely of carbon dioxide and carbon monoxide. This primordial atmosphere was stripped away, but as the planet began to cool and the molten rock solidified, gases, including water vapour, carbon dioxide and nitrogen, were given off and a new atmosphere began to form around the Earth. This, however, was an atmosphere without oxygen; indeed, for the first primitive life forms that began to develop, some 4,000 million years ago, oxygen was a deadly poison.

Then, about 3,000 million years ago, there occurred an evolutionary event of crucial importance the appearance of organisms that could tolerate the free oxygen they discharged into the atmosphere as a waste product of photosynthesis.

From these organisms developed the plants which are responsible for the oxygen-rich atmosphere which made possible the evolution of animal life, including man. We are all, ultimately, parasites on plants, and in particular on trees, which are the major contributors of the oxygen we need to survive. Trees, therefore, are an essential element in man's life-support system. If we fail to protect them we shall ultimately perish with them.

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