Recently I've been lamenting the loss of a maple tree in my backyard. A poor choice to begin with, after years of slow decline in less than ideal conditions it became clear we needed to remove it or chance damage to the house in the next bout of high winds.
Leaves on one large branch looked anemic one year, then small branches began to slough off. Local woodpeckers began to do their little feasting circle hops around a main trunk, and near the end the tree began to weep black streaks of sap.
This was my introduction to bacterial cankers in trees.
Since then, on walks with my dog I've started looking for signs of the canker in other trees throughout my neighborhood. Unfortunately, I've found it. These are photos of a neighbor's damaged live oak, proof that even our native trees are suffering.
This link from the Forest Service says that Hypoxylon Canker is not the cause of tree death. However, the fungus will infect the sapwood of trees that have been stressed by drought, heat, nutritional deficiencies, soil compaction, or a list of other conditions we've found all too plentiful over the past few very dry years.
Not all bacterial cankers are the same. This link from Penn State describes another one known to affect stone fruit trees under cool, wet conditions.
It's worth giving both of these links a visit - they're packed with information. Thanks to my friend Jerry Naiser, owner of Arbor Consulting, Inc. and Real Green Pest and Lawn, for steering me to the Texas Forest Service site.
All material © 2015 by Vicki Blachman for Playin' Outside.
Unauthorized reproduction prohibited.
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