How does Gaia resemble a redwood tree?
If you find it hard to believe that anything as large and seemingly inanimate as the Earth is alive, then it may help to compare the planet with a giant redwood tree. The tree is undoubtedly alive, yet more than 97 per cent of it is composed of dead wood. The thin circumferential skin of living cells (known as the cambium) just beneath the bark is what keeps the tree alive and growing. In a similar way the Earth also has a “cambium” composed of the surface layer of living organisms spread thinly over its circumference. The bark and the atmosphere both protect the living matter at the surface. All the gases of the air nitrogen, oxygen, carbon dioxide, and methane are the direct products of living organisms, except for the 1 per cent contribution made by the noble gases, such as argon.
