Use a 12- to 14-inch platter for the base. For the first level, assemble nine doughnuts in a ring with three doughnuts in the center of the ring. Stack another doughnut on each of the 12 donuts.
For the second level, assemble seven doughnuts in a ring with two in the middle, then top with another layer of 9 doughnuts.
For the third level, make a ring of 5 doughnuts with one in the middle; repeat the layer. For the fourth level, make a ring of 3 doughnuts; repeat the layer. Top with a single doughnut.
Add food coloring to your favorite glaze recipe and dip doughnut holes into the glaze. Position the doughnut holes in openings to add color. The top doughnut on the tree can also be dipped in colored glaze. You can also add sprinkles, nuts or drizzle the "tree" with icing.