staining on oak trees with die back

[macrocarpa]

Huge black oaks, 1/2 of the canopy already dead on 2 trees side by side (too far gone to save). Adjacent healthy black oaks may need protected?

I see this every now and then, along with frass usually.

The black staining has to be indicative to a specific root rot? I have also seen similar staining on trees infested with ambrosia beetles once the fungus is introduced.

Any ID advise is appreciated!

http://www.flickr.com/photos/53981946@N04/6210769120/in/photostream

http://www.flickr.com/photos/53981946@N04/6210769386/in/photostream

http://www.flickr.com/photos/53981946@N04/6210257223/in/photostream/

 

[KTSmith]

Nothing super diagnostic here without other information. Does the black ooze have a smell? I bet the ooze itself is pretty light-colored, but is associated with that black stain which forms on the bark wetted by the ooze. Healthy oaks of most any big size often have bacterial wetwood in the core of the tree. In and of itself, not a problem.
The photo ending in "223" looks to be a sapwood rotter like Trichaptum biforme. The photo shows the growth habit nicely but is useless for much else. Does the underside of the little bracket-shelfs show shallow spines? If so, that's where the pore walls have broken down and is pretty characteristic of the Trichaptum group. Are the margins on the underside of fresh little brackets violet in color?
Irrespective of the precise ID, those little mushrooms indicate more-or-less extensive decay of sapwood. Not a good sign. They aren't likely the primary cause of the crown dieback.
Might be a root rot, not enough info to tell. Any recent construction or changes in grade/soil conditions?

 

[macrocarpa]

only thing I can answer now without going back to the site is: major construction around these trees took place 6-7 years ago.

thanks

 

[guymayor]

[ QUOTE ]
only thing I can answer now without going back to the site is: major construction around these trees took place 6-7 years ago.

[/ QUOTE ]

Well there ya go. To diagnose, tap with hammer and pull off dead bark to get more clues, but root death leads to tree death; the other organisms involved are opportunists.