All those discussions of magic got me thinking about another angle. The elves have named trees in their glades. I think these trees should have magic themselves. Possibly they could actually be sentient (although there's no way to communicate with them unless you have magic yourself? Or unless you're an elf? Or both?) There could be other magic trees and plants along the same line in the wild, especially twisted ones in evil areas.
They could provide subtle bonuses and protection against hostile magic to the area around them; maybe they could ward off vermin or the like. Crops would grow better. They could possibly do more flashy things, too -- attack with their branches, bring lesser trees to life to fight, prevent water from freezing over in the winter, etc. The powers could depend on the type of trees (evergreens and other trees from the cold north might have the power to make water freeze, say. Magical trees might be able to impose their natural environment on the area around them, or do it automatically, so a sapling of a good-aligned tree might cure a tainted evil area, or vice-versa.)
Offerings could be made to them. Rare soils? Fine wines poured around their roots? More evil (less elven) trees from evil lands could want blood and decaying corpses.
The elves could offer saplings of their trees to particularly favored allies. If anything happened to those saplings, it would be BAD for relations with the elves, of course.
If you can communicate with them, they might be able to give you news from far-off areas, by whispering with other trees. Perhaps if there's nobody nearby who can communicate with them, they could choose a child who is born after they've been planted, and grant them the ability to speak to sacred trees. These trees could come to be worshiped as deities, even.
Just some idle thoughts.