Right up to the end of Garand production in 1956 Garands were fitted with walnut stocks, although some of the last ones were apparently stocked with birch. Birch stocks were used widely as replacements and you will also see low quality walnut stocks which were used in the late '50s/early '60s. Walnut was specified for national match rifles, although Birch was also used on some. I've got a Birch NM stock with all of the specified mods. A tiger striped birch stock ban be quite pretty.
The Danes used Beechwood for their replacement stocks and the Italians used good quality walnut throughout. Some of the worst stocks I've seen are Greek made, altho the Koreans apparently made some fugly ones too.