Artificial trees are often referred to as silk trees though they are rarely made from silk. This term was first used over 100 years ago when artificial flowers were made from silk. Silk being the only technology available a century ago and closest material they could use to recreate the color and texture of the petals and leaves of a plant.
These days silk trees are made with synthetic fibers and materials to recreate the texture and shape of the natural plant. Some are so cleverly recreated that they look almost identical to the real thing.