This has been a very interesting thread.  I hadn't thought about the
drier climate damaging the actual piano structure.  I live in interior
California, which can be dry much of the time (although in the past
few years our climate has been more humid -- in spite of the drought!).

When I go to tune a piano that has been recently moved from the Bay
Area (lots of folks sell their very valuable, but small bay area homes
and buy a large home with acreage here to retire; yes, property values
vary that much within California), I usually find them a half-note
flat.  So even short moves do effect one's piano.

I once owned a beautiful wooden boat (for those that are curious, a
16' double ender, cedar on oak ribs, Honduras mahogany topsides, steam
powered) that was built in the San Francisco Bay Area and I lived in
the Northern California mountains.  Despite keeping salt water in the
bilges, the top seams opened up a bit while there.  When I moved down
to the Central Valley of California, the seat seam opened up a half-inch,
and other glue joints started separating.  Wood does move a lot.

Sad to say, I no longer own that boat -- which disproves the theory of
the two happiest days of a boat owners life (the day he buys it, and
the day he sells it).

David Dewey