The European Silver Fir (species name: Abies alba) has the distinction of being the first tree species that was used as a Christmas tree in Europe. The tradition of using a small conifer tree with decorations originated in the upper Rhineland region of Germany and in the area around Basel, Switzerland. The name Silver Fir I believe comes from the fact that when this tree is viewed from below the white stripes on the undersides of the leaves give the tree a silverish color.
The difference between the European Silver fir and the Nordmann fir (which is now a more common Christmas tree in Europe and is becoming popular in the US) lies in the arangement of the needle like leaves. The leaves of the Abies alba have a flat arrangment as opposed to the Abies nordmanniana which has leaves that grow in all directions from the branch.
The tips of the leaves on the European Silver fir are rounded and not sharp which is a plus for a Christmas tree species. Also if you look closely the leaves have a small notch on the ends.
The range of the Abies alba extends from the Pyrenees mountains of Eastern Spain north to Normandy and East to the Balkans. The pictures for this post were taken in the town of "La Molina" in Cataluña (which depending on who you ask is an autonomous region of Spain or a region in its own right that wants to be a nation)
Another tree used as a Christmas tree is the Norway Spruce.
Looking for a new Christmas tree ornament idea? Check out these "Nativity Scrolls"