April 26, 2014

1 - A repair graft may be used to help repair ripped bark damage from branch breakage due to strong winds.

Yard and Garden April 26, 2014


The wind broke a big branch on my apple tree. When the branch broke, a large strip of bark was ripped down the trunk. Should I seal the wound with cement or asphalt to keep insects out?


You should not try to seal the wound with cement or asphalt. These materials will actually interfere with the natural wound closure mechanism of the tree.

If the edges of the ripped bark are pulled loose from the trunk, you may need to trim the loose bark. If you want to apply any covering material use a light colored latex paint. However, even this covering is not necessary.

Wounds from branch breakage are larger than pruning wounds and may take significant measures to encourage wound closure. If the area of ripped bark involves a significant percentage of the circumference of the tree or if it extends a long distance down the trunk, you may want to try a repair or bridge graft to provide tissue to more quickly close the wound. This type of grafting is often used to treat damage from girdling by animals or damage involving a horizontal wound at the base of a tree, but it may also be used in the case of ripped bark damage.

A repair graft uses one or more small branches from the same tree to bridge the wound. It is important to ensure that the cambium of the bridge material is in immediate contact with the cambium on both sides of the bridged wound. The cambium is a layer of dividing cells that is critical to successful grafting. It is located just under the bark or epidermis of the branch

If the wound is large, several bridge pieces may be used. By using several bridges you increase the chances that one or more grafts will be successful. If the bridge pieces cross the wound in a diagonal manner so that one end is higher than the other end, be sure that the top of the bridge is the original upper portion of the branch. A characteristic of plants is polarity in which the movement of hormones and materials in the vessels of a branch move in the appropriate up or down direction. If the bridging branch is upside down, it will not grow properly.

You can find information explaining how to properly perform this type of graft by looking online or in books under the topic "bridge graft" or "repair graft".

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.


For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms.

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