*************************************************************
WINTER
BY
Some trees have a
hard time making it through a winter. This is true whether they are in
the open, in a new development, on an acreage, or protected in an old
neighborhood. Winter sunscald and frost crack can be a real problem.
FROST CRACK AND SUNSCALD INJURY
BY
FROST CRACK
Long vertical bulges or cracks on trunks indicate a recurring
stress. The common term "frost crack" is misleading because frost or
cold does not initiate a seam or crack.
Cracks or seams start at wounds or branch stubs. Serious damage
can result from seemingly minor wounds. A sudden, sharp drop in winter
temperature causes the outer layer of wood to contract more rapidly than
the inner layer, which can result in a long vertical crack at weak
points in the trunk.
"Frost cracking" can occur repeatedly in the same place, causing
a buildup of tissues and the formation of frost ribs or seams. Depending
on the tree species, the tissues at the margins of the injury may grow
so rapidly that they curl in on themselves, preventing complete closure
of a wound.
Avoid wounds to the trunk and properly prune branches to prevent
the formation of frost cracks.
SUNSCALD
Sunscald injury occurs during late winter or early spring when
the temperature is above freezing during the day and below freezing at
night. During the day the tree tissues, warmed by the sun, become
active. Freezing at night kills this tissue, resulting in an elongated
canker (wound) usually on the south and southwest sides of the tree.
Sunscald injury is characterized by an elongated sunken, dried, or
cracked area of dead bark.
Thin barked trees such as
maples, ornamental cherry
and
crab apple trees are most susceptible to sunscald injury.
To prevent sunscald injury, shade the susceptible tree or use
tree wrap on younger, susceptible trees to reduce the warming of tree
bark during the day. Wrapping trunks of susceptible trees with
protective tree wrap should be done after leaf drop in the fall and be
sure and remove this wrap in late spring.
Sunscald injuries to tree limbs can be minimized by avoiding
heavy pruning of trees which have dense canopies, such as
maple.
Gradual thinning of limbs over a period of years is preferable,
particularly on thin-barked trees.
In
Also,
Sugar Maple has and is being planted on certain streets
as an “under story” street
tree,(i.e. where large
American
Copyright 2014
(Next week I will continue with |