We have an example of this two gardens down from us: white, dead wood showing all over a large, mature lime. I'll try to get a photo when the light's right, although it may not show sufficiently well in a snap.
The drey to whose occupants I attended a couple of years ago, and which is only 30 yards or so from the lime, was re-occupied this breeding season. Over the winter, almost every thin twig, and certainly all the new ones, were stripped. The previous owners used to take their own anti-squirrel action when they had little visitors and as a result their tree was pretty much untouched (alt