Hi, I own a Brazilian Rain Tree and want to apply moss on the trunk and top of soil? Is this ok, what is the purpose other than looking lovely, and how do I do this?

Never have moss on the trunk. The purpose is asthetic and usually only for when displaying a tree.

JumpinpAzure wrote: Hi, I own a Brazilian Rain Tree and want to apply moss on the trunk and top of soil? Is this ok, what is the purpose other than looking lovely, and how do I do this?

Moss can help hold soil on, so that hard rains don't wash it away. It also climbs up the tree trunk and helps rot the bark away. 

I would put the moss around the edge of the pot and keep it a centimeter or so away from the roots.