Folk metal is usually melodic, but I wouldn't lump for example Finntroll (folk metal) and early Children of Bodom (melodic metal) in the same genre.

EDIT: Listened through it. Very nice playing, very nice composition.

Children of Bodom used to be way better than this.

The original song from the video I posted of Children of Bodom

http://www.videosift.com/video/Children-of-Bodom-plays-some-classical-song-on-guitars

Silent night, Bodom night!