Excellent, thank you. That answers almost all my questions.
Now if I only could lure a developer here here to give us some cold hard numbers on these land types modifiers...
And I still want to know if multiply modifiers affect each other. If I understood your correctly you have said that you don't think so but that you are not sure. Anybody else can comment on this one?
P.S. Just to clariy - you feel that because Forest lands are better for Nature, Barrens (meaning Waste?) better for for Fire and Water/Death for Swamp, those land-types should be first one to be seached for these elements, even if there are Mountains (which gives you the best _general_ modifier) available, correct? And what about sea province? Are they the same as Plains in both magic site frequency (0 modifier) and no preferable element type? (the obvious pereferable element for the sea provinces would be water of course, but I don't seem to be fiding that many water sites in the ocean in my games.)