Katrina is a tree that Ryan Higa broke up with in the video Falling in Love with a Tree (Dear Ryan) the reason for their breakup is due to drugs, the drugs was weed literally weeds. Her breakup was hard for her as she told her friend, Bush. Her other friend is Barock, a random rock who appears to be jealous of Bush as their names suggests it like most of NigaHiga's Videos was covered in bad puns
Thumbnail
Her first appearance was in the video: Falling in Love with a Tree (Dear Ryan)
Katrina has never made an appearance in any video since then.
Her name is pronounced as Ka-tree-na Barock's name is pronounced Ba-Rock and bush is just bush