I'm trying to understand better how plants survive the winter in
cold climates.

I know about leaf abscision, annuals and perennials, the
withdrawal of sugars into storage roots, reduction in metabolic
and growth rates, etc., but I don't understand how plants avoid
or survive the destructive effects of freezing water in the
cells.

If I've got the numbers right, ice is about 9% less dense than
liquid water. I would think that ice crystals, as they form,
would rupture membranes and cell walls, causing irreverible
damage to the cells. Isn't this what happens to animal tissue
when it is frozen?

As we have seen in the news, this is a problem for fruit trees in
California and Florida - with freezing destroying the fruits and,
if it gets cold enough, the trees.

But how do cold weather plants handle it?

Do cold weather plants continue metabolism and generate enough
internal heat to keep from freezing? Do they manage to expel
enough water that freezing is not a problem? Do they have cell
walls that are tough enough to contain the freezing water by
compression and prevent crystalization (i.e., leading to
"supercooled" water)?

Thanks.

Alan