Giant Black oak unusual limb failure

[baumeister]

This Black Oak is approximately 100 feet tall, has a canopy spread equivalent to its height with many 20" plus diameter horizontal structural limbs. The canopy has a health condition of approximately 6 on a scale of 10. There is some dieback in the tips of the tree. This Oak has suffered two major limb failures that were not in conjunction with storm activity. The limbs were large diameter, horizontal structural limbs in the lower third of the canopy. Their failure was without warning. First failure was 1 year ago. The second limb that failed (about 2 weeks ago) fell onto the clients property (tree belongs to neighbor) and did major structural damage to a building that is actively occupied by frequent weekend activities. This failed limb was the first structural limb from the bottom of the tree. It was at about 20 feet from the base. The failure was due in part to heavy decay at the branch attachment. The limb failure caused a large piece of the trunk below the limb to split out with the limb resulting in a wound that extends into the trunk core and runs the entire length of the trunk down about 18 feet. Due to the unusual nature of this wound and the signs on the trunk itself, I suspect the presence of Red Rot. The picture is the base of the wound from the failed limb. I need help on the I.D. for red rot.

 

[guymayor]

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I need help on the I.D. for red rot.

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No idea what you mean by red rot.
No idea what 6 out of 10 means as far as tree care goes.
But we do know that big heavy sprawling limbs with bad forks need to be reduced or supported, or they fail.

 

[Toparboring]

I am with Guy what is red dot? did the inner hard wood or the branch contain any fungus that would be signs of heart rot. Most of the time they just break off. Heavy loaded branches need to lightened up of cabled.