A Few Important Hints
It goes without saying that to prune the proper way requires a basic
knowledge of the anatomy, biology and, yes, mechanics of that living being -
the tree. Otherwise you will have weakened, diseased and, later on,
hazardous, pest infected trees.

TIPPING, means removing the tips all the way around the tree; remember that
this also implies removing proteins or the precursors.

TOPPING, as it often is practiced is really mutilation. We starve the roots
when we remove the tops which supply their FOOD. This may later lead to root
rot.

POLLARDING, mean establishing the framework i.e. the size and shape of a
tree. This has to be begun when the tree is young and repeated yearly by
removing the sprouts without injuring the swollen areas and without leaving
a stub. It is not only tree care, it is an art and avoids later improper
tipping or topping. Appropriate SHAPING involves removal of crossing
branches within the crown and the pruning of V-crotches i.e. removal of the
lesser limb of the V and preservation of the dominant one. This avoids later
"including of the bark", a site for wound infection.

This leads us to the concepts of DOSE, TIMING and NATURAL TARGETS. Just as
you can only add an appropriate amount of water and elements, there is also
an appropriate amount , a dose, of tree which you can remove at a given
time. A young tree with its very thin periderm and cortex can be pruned a
hundred percent i.e. close to the ground, as is done in nurseries. A sprout
from a new site will then grow from the stump. There is no dead wood
shedding in a young tree but as the tree matures only the dead wood should
be removed. Natural targets such as the branch collars should be left in
place without leaving a stub.

The fact that there are three crowns to a tree adjusts it to the weather.
The innermost crown functions when it is hot, and the outermost when it is
cool. And then there is an intermediate zone. Thus one should be aware of
the possibility of overpruning, the real reason for what is often called sun
scold, frost cracks, pests and lightening.



For much more on pruning:

http://www.treedictionary.com/DICT20...ing/index.html


--
Sincerely,
John A. Keslick, Jr.
Consulting Arborist
http://home.ccil.org/~treeman
and www.treedictionary.com
Beware of so-called tree experts who do not understand tree biology.
Storms, fires, floods, earthquakes, and volcanic eruptions keep reminding us
that we are not the boss.