Dunedindan,

With the bays and the ambrosia beetle that cause it the canopy generally turns brown all at once. Tomorrow go look at the trunk for toothpick shaped objects (frass) sticking straight out of the tree. If it has it the tree is done sadly.

I've got spiral whitefly in my yard (a different problem) and I'm watching various plants deal with it. Some recover. I'm going to lose some things I'm pretty sure. But I let a croton go completely bald and it came back from the dead a year later, which makes me think that I need to ride this out with each plant to see what can survive.
Not sure if that helps, but unless it's threatening to fall on your house, it might be worth it to ride it out and see what happens.

I don't see those tubes so maybe it's something else.
Btw... There are 2 screech owls that have been using the tree to sleep in the past few months.

Glad it does not appear to be the Ambrosia beetle. Like I said when the canopy goes brown it happens fast and it is the entire canopy. We have lost 100's of bay trees in the neighborhood to them in the past couple of years.

FWIW, an update. The top 2/3 of the tree wilted but seemed to slow or stop spreading. I was sick of looking at it so cut of the 2/3 probably summer of 2013. Tree has come back ok so far and am hoping for it to fruit again.

A neighbor had the same thing, they cut it down to a stump and it came back. But it now has the wilt again.