In order to gather as much light as possible,
a tree's branches and leaves are arranged
according to precise geometrical laws. The
expression of these laws in each individual
case is modified by the particular local
circumstances, so that the shape of the tree
reflects the interaction between its genetics,
the characteristics of the site where it
grows, and the events that occur during
its lifetime.
As organisms which exist for the whole
of their lives fixed in one place, trees are
moulded by the prevailing influences of
that location. Thus, each species has a
basic or typical shape, which is modified
by the complex interplay of environmental
factors - the soil conditions, the prevailing
wind, competition from other trees, sun-
scorch, drought, storms, frost, lightning, slope,
shade, browsing animals, insects, fungi, and
the varying annual fluctuations of the
seasons, all contribute to the architecture by
distorting the intrinsic shape of the tree.
Additionally, there are the effects of human
activity.
One of the marvellous things about science,
is that it is open-ended. Nobody knows
whether we now know almost everything
that could be known, or only the tiniest
fraction. One fact which the history of
science so far demonstrates is that the
more we look, the more strange things we
find. It is therefore more than probable
that there is still much as yet unknown
concerning the less obvious aspects of the
life of trees.
It is known that the rainwater dripping
through the canopy and running off the
twigs and branches gets enriched by
nutrients leached from the leaves
themselves, and from micro-organisms
living upon the surfaces of the leaves. This
would seem to imply an interesting linkage
between the canopy and the roots.
The leaf surface, or phylloplane, carries a
complex arena of microscopic life. Dust,
spores, pollen, and bacteria are all sieved
out of the air by the leaves.
The bark of trees can carry a very varied
community of insects, mosses, lichens, and
bryophytes. In fact, the whole tree, from the
canopy above, to the fan of roots beneath
the soil, hosts many micro-environments
which probably interrelate in many
complicated ways. Much of this seems
only poorly researched to date.
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