That's all right, Ben - always glad to help!
actually, the common idea of an evergreen tree "not shedding its leaves" ia wrong - they just do it all year round, a few at a time.
Have you noticed, BTW, how rare ordinary rain is in Fantasy? It's nearly always either dry, or a violent storm, or snow, for some reason. Perhaps it's because a lot of writers ignore the mechanics of a rain shadow, as you mentioned.