Christmas tree flocking is made from a variety of materials, including cellulose, cotton, polyester, and polyurethane foam. Cellulose is the most commonly used material and is made from ground-up paper products, such as newspaper or cardboard. Cotton is a natural fiber that provides a softer and more fluffy texture to the flocking. Polyester is a synthetic material that is used to create a more durable and long-lasting flocking. Polyurethane foam is a type of plastic that is used to create a more rigid and durable flocking.