My girlfriend got me this Japanese Juniper and it has what appears to be sphagnum moss built up around the trunk. I was wondering what the reason for this might be. Also if you have any advice for me on this tree I’d really appreciate it.

Ghinton wrote: .. Japanese Juniper and it has what appears to be sphagnum moss built up around the trunk..

The moss is there probably to keep the humidity high; you don't have to keep it if you water the juniper properly.
It is a young tree, and could have a cascade style in the future.

Your plant looks ok, but I hope you only took it in to take the picture. I will be dead in months if you have it inside.

Ghinton wrote: My girlfriend got me this Japanese Juniper and it has what appears to be sphagnum moss built up around the trunk. I was wondering what the reason for this might be. Also if you have any advice for me on this tree I’d really appreciate it.

Essentially, what you have is a very young juniper, untrained, not styled, with some decorative material to make it look like something.

Plant it in the garden, leave it there for a couple of years so it can grow. Meanwhile, start studying bonsai.
Do not keep it indoors, it will die.

I live in Alaska. It’ll die if I put it outside. What are my options? I was thinking window sill. They probably get cold enough to put it into dormancy. The guy that sold it to her said it was eight to nine years old and could live indoors. He told her some other bullshit to though so I’m trying to figure it out

Ghinton wrote: I live in Alaska. It’ll die if I put it outside.

Depends. What USDA zone?

3b I do believe

Ghinton wrote: 3b I do believe

So −37.2 °C to −34.4 °C?

This juniper can handle zone 4 (-34.4). So yeah... your zone is a little bit too cold.
Got an unheated space?

I don’t. If I shit the heat off in the garage it messes with the temperature in the house

Ghinton wrote: I don’t. If I shit the heat off in the garage it messes with the temperature in the house

Well.. if you cannot find a solution, you can choose to let it freeze to death outside, or to let it die slowly indoors.
It will live indoors, it may even live pretty long, but eventually the climate indoors and the lack of a dormant period will kill it.