I have a question. The Bosmer made the Green Pact with Y'ffre that prohibits any use of wood or vegetables of Valenwood. Now two questions:

1) Does this Pact apply to other regions of Tamriel aswell? I can't imagine why it shouldn't. Furthermore, the Bosmer are carnivores that means that they don't eat vegetables from other provinces aswell.
2) Why are Bosmer good at alchemy if they aren't allowed to harvest any plants? Is my character allowed to harvest plants in Skyrim?

Strangely, they appear not to have any problems using plants and resources from other provinces (in "dance in fire" imported wood appear to have great value)

Using it, but are they also allowed to harvest it themselves?

http://www.uesp.net/wiki/Lore:Green_Pact

So it seems like they're not allowed to eat any plants regardless of where they come from, though using them for other purposes is okay if they're not from Valenwood (also they're supposed to eat all enemies they slay). A bosmer alchemist wouldn't be able to eat plants to figure out their properties, but would be fine otherwise. Bosmer born outside of Valenwood however might not adhere to the pact as strictly though.