I am not logged into the game, so I'm not 100% sure, but I believe cailun paper can be made from Tier 2 wood or roots (harvested from Antonica or the Commonlands).
If you are a craftsman it should be in your craftsman essentials volume 10 (or 11) book; if you are an outfitter or a scholar, you will need to purchase Timbercraft Essentials Volume 1 from the vendor in the wholesale tradeskill instance.
Hope that helps!