Add the Berries/Ornaments
From a 3/8-inch dowel, cut 80 berries, each 1/2 inch long. Use a hand saw with a miter box or miter saw to cut the pieces.
On each of the tree sides, randomly mark 20 spots for berries, and drill 3/8-inch-deep holes using a 3/8-inch Forstner bit (Image 1).
Paint the berries using red spray paint (Image 2). To make it easier, insert the berries in a foam-core board so they stand up in place. Punch holes in the foam-core board or use the 3/8-inch Forstner bit to drill holes.
Apply a dab of glue on the bottom of the berries and insert into the holes in the tree sides as shown in Image 3. Use a wooden or rubber mallet to tap the berries in place if needed.