Odd Lichen Phenomenon

Shagbark Hickory (Carya ovata) with heavy lichen growth at the ends of the shag. Mansfield Center, Connecticut, January 2017.

Poking around the local woods during one of the many thaws this past winter, I came across a Shagbark Hickory with an unusual growth of lichen on its shaggy bark. The peeling strips of bark were heavily colonized by a big, gray foliose (leafy) lichen that I can't immediately identify.

Foliose lichen on Shagbark Hickory bark strip.

The lichen was mainly on the splayed tips of the bark. One could come up with an explanation of why the lichen was so vigorous on those spots: rainwater would flow down to the ends of the bark strips, keeping things moist and accumulating nutrients leached from the tree's surface. The problem is that there are hundreds of other Shagbark Hickories in the area, and it just seems to be this one tree that is festooned with such a heavy growth of this particular lichen. Maybe there is something especially conducive to lichen growth in the microhabitat of this one northwest-facing steep slope above a swampy hollow? It's difficult to say with just a single, isolated example. 

Another view of the licheny Shagbark Hickory.