When cutting out the discs try and cut as near to the edges as possible so you get all of them out. There will probably be lots of leftovers, I made cakepops with mine. One other thing, I am making this cake slightly smaller as it was a little unstable at the height it was and I'd hate for it to topple over after all of your hard work.
You will need1 cake board (at least 6 inches)
4 pieces of coloured sugarpaste rolled out and made into small circles and stars for the baubles and one larger star for the top. I sprayed my stars with gold lustre spray.
2 (10 x 8) trays, greased and lined
Set of cutters starting from 4 inch
preheat the oven to 170
420g S/R flour
350g caster sugar
400g stork margarine
2 tsp Vanilla bean paste
Mix all of the above together in an 'all in one' method. Spoon into prepared tins and bake for 25-35 minutes until golden and when it springs back when touched. Leave for at least a couple of hours to firm up and cool completely. Then start to cut out discs of cake, starting with a 4 inch cutter, then a 3&1/2 and so on finishing with a 1&1/2 inch cutter.
For the buttercream
2kg icing sugar
1kg unsalted softened butter
Green gel colour
2 tsp bolling water
Mix the icing sugar and butter together until light and fluffy. Then add the colour, start with a little and work up. Then add the boiling water, whip together until even in colour. Spoon 2 thirds into a piping bag fitted with an open star nozzle and put the rest into a bowl to sandwich the cake together and crumb coat.
Buttercream the discs of cake into a pyramid shape. Then add the dowels, cover with a crumb coating of buttercream, and place into the fridge or freeze until firm to touch. I'd do this bit in situ, starting at the bottom of the cake pipe on the tree branches, holding the bag horizontally and pulling towards yourself, moving the cake round as you go. Once the cake is totally covered you can then add your decorations. I've given instruction for sugarpaste baubles and stars but you could let your imagination run wild. Tiny candy canes and gingerbread men would look really cute, along with presents around the base. Also it would work really well with my chocolate mud cake adapted up to fit the tins.