of Rhode Island GreenShare Factsheets
splitting can occur in response to various environmental factors
at different times of the year. Splits can occur on the trunk of
the tree as well as on branches. Trees which are most susceptible
to this type of injury are those which are thin-barked, such as
certain fruit trees. Newly-planted trees or young trees are more
prone to bark-splitting. Bark splits are not likely to be fatal
to trees; although they will, in some cases, allow entry of disease
organisms which can cause decay. Through proper treatment to encourage
the natural callusing process, a tree should be able to close most
is no single reason for bark splitting on trees. During late
and early spring, severe cold followed by rapid thawing can result
in splits referred to as "frost-cracks." These "frost" cracks
can actually start from a wound inflicted earlier in the
Sometimes the crack may remain in the internal wood, but frosts
can cause the crack to expand and split the bark. Excessively
growth in the fall, stimulated by warm temperatures, high humidity
and high nitrogen levels, can increase susceptibility of
growth conditions may also cause splitting of bark. Dry weather
(which slows growth) followed by wet or ideal growth conditions
may cause an excessive or vigorous amount of growth leading to splits
in the bark.
especially in winter months, can cause bark injury to thin-barked
or young trees. Although an exact split may not be seen immediately,
the outer layer of bark will peel away from the affected area in
the summer following the winter damage. Sunscald injuries to tree
limbs can be minimized by avoiding heavy pruning of trees which
have dense canopies. Gradual thinning of limbs over a period of
years is preferable, particularly on thin-barked trees. Newly-planted
trees may be protected from sunscald by wrapping main trunks with
mentioned before, certain trees are more susceptible to splits than
others. The trees on which we receive the most inquiries concerning
splits are Kwanzan cherry, maple and fruit trees. Any newly planted
tree, especially of a thin-barked species, is a candidate for bark
splitting if it is not cared for properly. Be particularly careful
to avoid fertilizing trees late in the growing season, as this may
promote new growth and predispose the tissue to winter injuries
(including bark splitting). Autumn fertilization following leaf
drop and dormancy should not lead to this problem.
When a split occurs on a tree, what should you do? In recent years
quite a bit of research as been done on closure of tree wounds.
These investigations have indicated that tree wound paints are of
little value in helping a tree to callus over. For this reason,
do not paint or try to seal a split with paint or tar. Tracing the
bark around the split can be very helpful in aiding wound healing.
With a sharp knife, starting from one end of the split, trace around
one side of the wound, about 1/2 to 1 inch back from the split bark.
Stop at the other end and do the same procedure on the opposite
side of the split. Knives should be sterilized between cuts by dipping
for several minutes in a 1:10, bleach/water solution or a 70% alcohol
solution to avoid contaminating the cuts. Carefully remove the bark
from inside the traced area. You should now have a bare area. Remember
to leave this untreated. A tree growing with good vigor usually
calluses over quickest. Encourage vigor in the tree with yearly
spring fertilizer applications and be sure to provide adequate irrigation
in hot, dry weather. Bark splits will often close over completely,
leaving a slight ridge in the trunk where callus tissue has been
from Thomas Kowalsick, Juliet E. Carroll and Margery L. Daughtrey,
Cornell Cooperative Extension, 2000
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
of Rhode Island Cooperative Extension provides equal program