Bark damage #2

Asked July 23, 2017, 8:43 PM EDT

Email 2: I have bark damage on 2 parts of a black willow tree. On the thinner trunks the damage goes as high as 4-6 feet and 10-12 feet. Some pieces are found on the ground. This is new as of this week. On the thicker trunk the damage is in wider sections and is at about 4-6 feet high. Photos attached of thicker trunk. Separate email/pics for other damage. What is causing it? What can we do? Will the tree be ok? Thx!

Carver County Minnesota

1 Response

Hello and thank you for contacting AaE for help.

And thank you for all the pictures in the two emails you sent. The best I can tell is that your tree may have Armillaria root rot. More information about Armillaria root rot is available on this U of Mn Extension web page.

Armillaria root rot
Armillaria spp.

  • Infected trees have poor growth, dead branches in the upper canopy, undersized and/or yellow leaves
  • Flat white sheets of fungal growth (mycelial fans) between the bark and sapwood at the base of infected trees
  • Thick black, shoestring-like fungus can sometimes be seen under the bark, around roots and in the soil around the base of the tree
  • Wood is decayed, white, soft and spongy; this may extend from the base of the tree well up into the trunk
  • Trees frequently break or fall over in storms
  • Clusters of honey-colored mushrooms may grow at the base of the tree in fall
To be absolutely sure you may want to confirm by sending a small bark sample from the whitened area to the U of Mn Extension Plant Disease Clinic. Here is a link to their web page describing their services and pricing. Or you can engage an experienced tree care professional to evaluate the situation and determine next steps.

Good-luck!