40 - EspritBonsaiInternational #101Treegazing
As with most pine,
the bark of this
old Scots pine is
deeply fissured.
Beneath thebark’s surface
Apart from its aesthetic aspect, the bark
of a tree is an attractive envelope that
protects the plant; less known is that it
acts as the tree’s waste disposal agent.
Author:
Louis-Victor Bourdeau
When trying to understand the structure and
the role played by a tree’s bark, one often
compares bark with the skin of animals.
This is an apt comparison allowing one to easily
understand its functions, but is insufficient as it
has so many more over and above the undeniably
aesthetic aspect.When the envelope fissures
Bark is made up of dead tissue, which plays
the role of eliminating waste as well as protecting
underlying tissues. Trees produce waste such as
crystals, gas, and dead tissue that are eliminatedby the bark. This flakes off fairly rapidly from the
trunk and falls to the ground.
The bark’s appearance is an essential criterion
for identifying and differentiating tree species. It
varies according to each tree and its living condi-
tions. The white smooth bark of a young birch does
not resemble the fissured bark of the pine. The fine,
grey and smooth bark of a beech is easily distin-
guishable from the thick, cork-like bark of the oak.
The differences can be explained by the manner
in which the bark is formed. As the trunk thickens,
its bark ends up by cracking. The speed of fissuring
depends on the flaking; that is, the rate at which
dead tissue falls to the ground.
If the bark on most species is smooth when
young, with age it takes on a completely different
aspect, which can vary according to the species.
Pine trees will keep their dead tissue for a long time,
so their bark thickens over a few decades, and then
will crack to produce its characteristically fissured
aspect. On the other hand, beech or hornbeam
rapidly eliminates dead tissue, which explains the
fine, smooth appearance of their bark.