Fig. 15.1. Cross section through
tree trunk.
The tight inner rings show normal growth of a
shade-demanding tree. The outer rings show
evidence of too much exposure to sunlight,
following its neighbours' removal.
expense of its upward growth. It develops a cone-shaped form, with
much growth of branches on the lower part of the trunk. These will
tend to grow on the sunny side of the tree, leaving it unbalanced and
misshapen.
In its early years, due to high light exposure, a plantation tree
exhibits wide annual rings and abnormal lateral branch growth (see
Fig. 15.1). Once it receives some protection from its neighbours, the
need for lateral branch growth diminishes and it will tend to grow
upwards. However, in commercial woodland, the trees are thinned
after a prescribed period, those considered suitable for use in con-
struction going to the sawmill and the remainder to the pulp-mill.
This thinning out exposes the remaining trees to excess heat and
light. All their growth energy is diverted to growing branches on the
exposed part of the trunk, mainly on the sunny side, which pro-
duces knots and twisted, spongy grain.
The annual tree rings tell the story of a tree's exposure to light.
In Fig. 15.1, the rings near the middle show that in its early years,
this 33-year old tree was exposed to unnatural levels of light and
heat. The healthiest growth was in middle third of the tree's life,
revealed by the annual rings at their closest. Its last years show the
stress it experienced when its protecting neighbours were removed.
High quality, resonant timber could be cut only from the area of
closely spaced rings. A board cut from the full width of the trunk
would warp as a result of the unevenness of the grain. For practical
purposes the only source of good narrow-ringed timber that is firm
and regular in its structure and less likely to warp, is a mature tree
from a natural forest. A shade-demander in a natural forest or a
plantation that is suddenly exposed to light will show irregular
annual rings, an off-centre heart, sometimes heartrot, and radial
cracks (called 'shakes') like those shown in Fig. 15.1. Excessive heat-
ing, causing sponginess in the wood that often results in heart rot,
and encourages bacteria and parasites causes the openness of the
grain. This combination of conditions Viktor Schauberger called
'tree cancer.'
The conventional theory is that the movement of sap is caused
by osmosis, or by differences in pressure between air pressure and
the pressure in the capillaries. However, the absorbent raising action
of osmosis is limited, and cannot account for the rising of sap in the
highest trees, which can exceed 91m (300ft). Mechanical suction
cannot be responsible either, as the limit for drawing up water is200 HIDDEN NATURE