The building is a shopping mall with ice skating rinks for the public and for private uses (national ice hockey team, for those in lessons). There are three levels. 1st level : Ice hockey stadium 2nd Level : large skating rink (for public) and shops 3rd level : smaller ice rink (for those in lessons) and shops. The lift starts from the first level and goes straight up, so there would be a linkway that links that level to the lift as the 2nd floor is smaller than the 1st, and the 3rd is smaller than the 2nd (so it looks like a christmas tree). The floors are in a shape of a flat cone as a christmas tree is in a cone like shape.
The building is shaped like a christmas tree because the main use of the building is the ice skating rinks. Since its ice skating, the themes related to this is snow, ice etc. Snow can be found during winter, and during winter there is christmas. During christmas there are things like presents, christmas trees etc. Using all these inter-related themes, the christmas tree was chosen because it's shape can be used for a building (using flat cones and decreasing the sizes for each, having the smallest floor at the top).
The intended use of the whole building is to provide ice skating rinks for the public to use and to host ice hockey competitions or let the national hockey team have a rink for them to practice. There are also a rink for those in lessons. It is also a shopping mall so people going there need not be ice skating, they can only be there to shop.