Choose spruce, pine, or fir, according to the species recommended for your area. Check with a local nursery for seedlings. Plant them in potting soil in terra-cotta pots; the ones shown are Italian rose pots, available from specialty garden centers and garden catalogs.
Cover the soil with pads of reindeer moss, which is available from floral-supply shops and crafts stores. If it's dry when you buy it, place the moss in a plastic bag and sprinkle it with water. Seal the bag and let the moss absorb moisture until it's soft.
Tie organdy ribbon around each little tree and attach a card with the name of the species and instructions for its care-for example, "Set the pot in a sunny place and water the soil well once a week. In the spring, plant the seedling outdoors."