Quercus agrifolia cankers?

[beastmaster]

I should of gotting some photos I know. These live oaks I am deadwooding in a small grove share a common symptom, on some of the branch junctions the bark looks like its been eating to the point of girdling some of them. I say eaten, but I don't think that is what is doing it, more like the bark is just falling off there. The limbs are still healthy. Rats were my first though, but on closer inspection there are no chew marks and its just where two branches connect. Is there a fungus or disease that does this? These trees are in So. Calif. and they seem a little stressed. There is a dead oak stump covered with cankers near bye. I have half a day left there so I'll snap some pictures when I finish, but for now any ideas? I'm thinking some kind of canker disease, but I can't find anything in any of my books. Thanks for any help.

 

[Urban Forester]

It could be P. Ramorum. Although fatal to some Oaks. Coast Oak has been found to have resistance. Its phenolic compounds (defenses) are different and allow the tree to survive. This could be an example. Where the one that died was overwhelmed by attack, this one was stronger and so walled-off cankers formed. Then I could be WAY out in left field :msp_unsure: You're right pics would help.

 

[ch woodchuck]

Somethimg to read..
Identification and pathogenicity of Botryosphaeriaceae species associated with coast live oak (Quercus agrifolia) decline in southern California (Diplodia corticola...possibly)

A small grove?Trees may be tied together by grafted root systems.What one gets they all get(sometimes)