to absorb. They are also responsible for transferring yang energy
and nutritive elements derived from the tree crown, to increase the
vitality of the soil, without which the micro-organisms would be
unable to flourish. In addition, they release hydrogen, which com-
bines with free oxygen in the soil to give birth to new water. So it is
clear that these protoplasms perform invaluable functions.
Even a gardener probably has only the vaguest idea of how a root
system develops. To hold up the plant stem is one purely physical
function. There is, in fact, the widest possible variety of root forms
and systems, the diversity of which is essential to healthy micro-
environment, because each species' roots go down to a different
level in the soil, bringing up different nutrients and energies.
Trees are described as being flat-rooted, heart-rooted, tap-
rooted and deep-rooted, the last evaporating more water than
heart-rooted trees, and flat-rooted trees evaporating least of all.
Each plant species, therefore, has its own particular root structure,
which penetrates to a different soil horizon to withdraw the ele-
ments it needs. But other plants will share some of these nutrients
also. Fig. 15.7 illustrates the wide variety of root systems.
When plants first appeared, about 420 million years ago, climatic
conditions were inhospitable, with severe storms and heavy rain.
Only the most primitive plants could gain a hold, feeding on the salts
and metallic minerals. Although they had very little root growth, the
stems above ground were able to trap some nutritive wind-borne
dust to form very primitive soil, their shadows having a slight cool-
ing effect on the ground, allowing some moisture to collect.Soil and nutrition
Cooling was the key to the appearance of water, and as the ground
cover spread, the lowering temperature affected the deeper ground,
allowing the water table to rise, bringing with it minerals, trace ele-
ments and nutritional substances nearer to the surface. This created
the conditions for higher quality plants to evolve. Requiring better
quality nutrition, these higher plants had deeper root systems that
brought up minerals from a different horizon, but were no compe-
tition for the pioneer plants.
The more evolved plants held the soil together, trapping more
moisture that helped to attract micro-bacterial activity to break
down the mineral particles into finer dust, the first step towards the
HIDDEN NATURE