Definition - What does Alliers mean?
Alliers is the name of a forest located in the Auvergne-Rhône-Alpes near the region of Sancerre that produces oak that is used for making wine barrels. In the forests where oaks are grown for barrels, they are grown in stands. This enables the trees to grow more up than out and creates tighter pores in the oak that are perfect for wine and brandy barrels.
WineFrog explains Alliers
Just as there are laws pertaining to wine, there are also laws for oak used for making wine barrels. For any wooden barrel produced, it must have 100% French-grown wood if it is to be labeled as French.
For oak barrels whose wood originate from specific forests, there must be a minimum of 70% oak from the said region. In France, there are five main forests where oak is harvested for the use of barrels: