there are several kinds of mulberry trees in korea. they grow in different climate conditions. each kind of mulberry tree produces different kinds of hanji, and they are all used in a different way. there are various kinds of korean paper, and they are named after their usage. "changhoji", for instance, is a kind of korean paper. "changhoji" means window paper. koreans used to glue "changhoji" on a door because it allows both air and light through it, thanks to its wide fiber. there are other kinds of "hanji" as well. when korean paper is used as a copy paper, it is called "bogsaji". it is used as paper for family registry book or buddhist scriptures. when the four gracious plants (plum, orchid, chrysanthemum and bamboo) or birds are drawn on "hanji", it's called "hwasunji", the drawing paper. nowadays, korean paper is used for arts and crafts.