I'm about to stack a 4 tier wedding cake, the bottom tier is fake. Do I need to dowel the bottom tier? I'm concerned the weight of the top 3 tiers will make the fondant bulge on the bottom tier.
If your fake tier is made of styrofoam, you do not need to dowel it. It will withstand perfectly the weight of the upper 3 tiers. It will not bulge, because there is nothing inside it that is moveable.
I was taught to always dowel fake tiers, so you will not get any movement and cracking in the top of the lower tier's icing or fondant or ganache...whatever you are using. The upper tiers need to sit on top of the dowels, which then distribute the weight to the bottom of the cake board.
Just my 2 cents. HTH.