the world's historical climate. In the first case they were evergreen
forests, interspersed with enormous swamps. In the Eocene when
the modern great mountain ranges were being uplifted, there were
large tropical jungles, perhaps not too different from the modern
ones which flourished on all the continents until the late nineteenth
century, but with less complex fauna.
It is interesting to speculate what caused the forests to establish
themselves at these periods. Viktor Schauberger recognized Nature
as an intelligent system endowed with meaning and purpose that is
concerned with evolving more complex life-forms and a higher level
of consciousness. From that perspective it is possible that the estab-
lishment of forest might be seen as part of that purpose.
Forest cover varies with climate. Forests have been the natural
cover of perhaps three quarters of the Earth's land surface during
these periods of evolutionary expansion. This natural forest was an
essential prerequisite for the development of the extraordinarily
rich variety of fauna and flora (now called 'biodiversity') that makes
this planet an important source of life in the Universe.Destruction of the forests
Either fortuitously or by design, there seems to be a large degree of
tolerance in Earth's ecosystems for the amount of forest cover
required to support a balanced climate — though what a great
reduction of forest does to biodiversity and the quality of life is
another question. Over the half a million or so years of humankind's
time on Earth, our species has been responsible for reduction of the
forest cover to about 25% of its optimum extent. The early agricul-
turists would burn clearings to grow their crops, and then move on
to allow the fertility to be replenished. Early civilizations, some well
documented and some which are now folk memories, felled vast
tracts of forest.
Many of these lands became desertified, such as the Gobi, Sind,
Arabian, Mesopotamian, North African and Kalahari deserts —
probably through a combination of deforestation and climate
change. Whole nations were uprooted and had to move elsewhere in
their search for subsistence. The same is likely to happen today
where great swathes of the rich equatorial forests have been cleared.
Fortunately in those days there was somewhere else for the dis-
placed to go, because the world's population was still relatively
HIDDEN NATURE