Why is American oak traditionally used instead of French?
Different people will come up with different explanations for this however, the most plausible seems to be that this dates back to the Spanish colonization of the Americas. During their great exploration years, much of Spain was deforested for shipbuilding. The Americas had an abundant source of oak which was shipped back to Spain for any number of uses, including uses in winemaking. This has never changed, although today, it has become fashionable for marketing purposes to tout the use French oak.