A tree’s life is hard. It must stand against wind, hail and
ice. A multitude of
pests wait to consume it. To live decades, maybe even
centuries, the tree must be tough.

To protect itself, a tree will wrap itself, inside and
out, in protective clothing. It
has to. When environmental problems or pests come to damage
it, the tree must stay still
and take whatever comes.

Life conspires to kill trees. They try to survive by
using a unique defensive system.

Actually, a tree has a double-edged defensive system to
deal with the environment
– one part passive and the other active.

The passive system is composed of wooden walls made from
strong, complex materials.
These include cellulose fibers, which are made of sugars so
tightly welded together that
few living organisms on earth have the enzymes to break them
apart.

Another material in wood is like epoxy glue. Called
lignin, it holds the cellulose
fibers close together. Lignin is composed of complex
chemical building blocks, each
connected in a different way to each other.

Again, only a few decay organisms can degrade lignin.
Very few living things can decay
both cellulose and lignin.

Cellulose and lignin are the main walls, floors and
ceilings of individual cells and
groups of cells. These wooden cell barriers prevent or slow
pests and decay from rampantly
consuming the tree.

As cells age and die toward the middle of the tree,
chemical reactions biologically
strengthen the wooden walls. Old cells generate a number of
toxic materials in their dying
gasps. These materials slow pest and decay organisms.

The active defensive system of a tree includes special
biological poisons it makes when
injured. It also includes a host of blocking, plugging and
sealing compounds.

The tree’s active defenses try to slow the spread of
pests and decay by producing
toxins dangerous to living things. Some of these toxins are
dangerous to humans at the
correct dose.

Of all the materials the tree makes to protect itself,
one of the most versatile and
effective is suberin.

Suberin is a waxy waterproofer and wooden wall primer.
Lightweight and low-density, it
is made of many similar building blocks the tree piles
together.

Chemically, suberin is a complex polyester. The tree can
make it wherever it needs it
to block passages or seal off areas.

The tree also uses suberin as a passive defense, like an
overcoat. That’s because
prevention remains the best way for a tree to defend itself
from infection or injury. So
the tree surrounds itself with the protective polyester
suberin.

People may know polyesters as a clothing fiber. But trees
produce them to stem the tide
of invading pests and decay. Suberin is one of the most
effective barrier or wall
materials in a tree. You can see it every day as bark.

Bark is composed of many things. It includes a large
portion of suberin to shield and
protect the living portions of the tree. Unfortunately,
unthinking or unknowing humans can
easily damage these bark overcoats.

Don’t be one of those careless humans. Support your local
trees and their important,
polyester overcoats.