A. Topping is the
practice of radically cutting back large branches on mature trees to
short stubs. In trees that grow with a single main trunk, it is
literally cutting the top off the tree. Topping is generally
employed when a tree has outgrown its space and is interfering with
utility lines, hanging over rooftops, or making the neighbors
complain. Topping is a poor substitute for proper plant selection (I
realize that many people inherit problem trees when they purchase
property). There are many lovely trees that provide shade and
shelter without getting so big that they pose a threat to property
and utility lines. While many homeowners think that they are
protecting their property by having large trees topped, it actually
increases the likelihood that the tree will become a hazard in the
future. Topping injures a tree in a number of ways, making it more
susceptible to infestation by insects and disease-causing organisms.
Weak water sprouts grow after
'topping' a Silver Maple
Topping removes a
large area of leaf surface very suddenly, thus limiting the amount
of food reserves it can produce through photosynthesis. There is a
balance between the crown (top growth) and root system of a healthy
tree. Topping removes so much of the tree’s crown that this balance
is thrown out of whack, and the tree is unable to provide sufficient
nutrients to its root system.
Also, topping is a shock, because a tree’s crown protects much of
the tree from direct sun. Just as a person who has not been out in
the sun can be severely sunburned when they go out on a sunny day,
so can the interior portions of a tree when that protection is
removed suddenly. In trees this is called sunscald, and it injures
and kills portions of the bark. These areas are prime targets for
infestation by insects and disease-causing organisms, as are the big
wounds left behind when large branches are removed.
Why these trees
Although people have trees topped to reduce their overall size,
trees respond to such drastic pruning with rapid re-growth. Often
known as watersprouts, the vertical, rampant growth that results
from topping elongates much quicker than normal growth. The tree
returns to its original height in a short time, defeating the
purpose of topping the tree in the first place. These watersprouts
are also much more numerous than normal growth, resulting in a crown
that is much more dense. They tend to be attached more weakly than
true limbs, so a topped tree winds up with a far more dense and
dangerous crown. The numerous sprouts tend to catch the wind rather
than allowing it to pass through the crown of the tree, making it
more likely that these large sprouts will come down on a windy day.
Finally, a tree that has been topped is an ugly tree. Topping makes
a mockery of the loveliest tree, and it will never regain its true
character afterwards. Topped trees actually reduce the value
of a property, while mature trees that maintain their true form add
value to a property. It may seem cheaper initially, since it takes
less skill and time than proper pruning, and generally does not cost
as much. However, topping costs more in the long run. If the tree
dies as a result, there is the cost of removal and replacement.
There is also an increased liability from the dense crown, weakened
branches and damage from insects and disease.
The basic structure of a tree is
forever ruined by topping
I have to agree
with the third company that gave you an estimate. Although the tree
should not have been topped, it is possible to thin out the water
sprouts, leaving the strongest and best placed and removing the rest
in order to restore the crown to some semblance of health.
Continuing to top this tree just adds insult to injury.
Fertilization should be based on the results of a soil test. Mature
trees have less need for fertilizer than other plants. If you have
not done so already, the tree would be best served by removing the
grass under it and replacing it with coarsely shredded hardwood
mulch. Grass is a ferocious competitor for water and nutrients, so
getting rid of it reduces potential drought stress for the tree.
Also, the mulch contributes organic matter and nutrients to the soil
as it breaks down. Ideally the mulch should be two inches deep and
extend from near (but not touching) the trunk out to the drip line
(the ends of the branches).