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 As tree trunks and limbs grow, they naturally shed bark and new
bark is formed. Usually this is in small pieces that don’t grab
your attention, but as an example sycamore trees tend to shed
bark in large strips.
Rather than a tree loosing bark in a large patch, the real
concern is probably what caused that to happen all at once. In
many cases, this is caused by one section of the tree trunk
growing and the remainder of the trunk not growing. The
expansion of the growing area means the bark gets loose at the
edge of that area. After a while, it simply becomes loose and
falls off. Unfortunately, the area not growing is usually a dead
area.
Dead areas on tree trunks come from many causes, with many of
them being a form of mechanical damage. Think of a mower scrape,
weedeater injury, bicycle rub, or transplanter damage as
mechanical. You can also throw chewing from four legged
creatures into the mix. Rabbits or mice chewing on trees can
cause dead areas. Same goes for rubbing whether from deer or
other branches being whipped by the wind. Areas may also be
affected by fungi, bacteria, and insects.
The one thing to keep in mind is that dead means dead. It won’t
miraculously go away. What the tree tries to do to compensate is
to heal around the dead area. This is evident with what is
called callus tissue. It is relatively smooth, and tends to
“roll” from the good wood until it covers the affected area.
Once completely covered, the outside looks “healed,” but the
inside part will still have the dead area contained in it. Dead
trunk areas frequently affect upper limbs, due to loss of tissue
which would have carried water and nutrients.
When evaluating what to do with a trunk injury area, it is
important to follow a few guidelines. Determine the extent of
the dead area. It the area is a significant amount of the tree
trunk, it may lead to safety concerns for people and property.
Is it dead and solid, or is it also decaying? Decayed areas
affect the integrity of what is there, and may enlarge the
affected area.
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To do an assessment, you can use something pointed (ice pick, awl,
or small Phillips screwdriver) to determine if there is decay.
To assess the depth, you can actually use a drill and bit to see
how far in the dead area goes. A rough assessment can be made by
seeing where the callus tissue begins on either side of the
wound.
Location, extent of damage, and the offsetting benefits of leaving
a tree all go into the decision to remove or leave it. Severely
damaged trees adjacent to homes, buildings, and vehicles should
probably be removed. A severely damaged tree which would not hit
anything if it falls, is easier to leave. This gets a little
trickier if there is potential for damage, but the tree is the
only shade you have for the patio. If you decide to leave the
tree, remove decayed material. Sometimes filling larger voids
with items ranging from plaster of Paris to bricks and mortar is
done – just remember where construction was done if you have to
cut the tree down at some point. Then, paint dead areas with an
exterior latex paint to discourage insects such as carpenter
ants.
[By JOHN FULTON, COUNTY EXTENSION
DIRECTOR SERVING LOGAN, MENARD, AND SANGAMON COUNTIES]
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