Oak Barrels and Wine Flavours....

, along with other woods, such as chestnut, that are used for barrels. However as the french  oak supplies are diminishing  eventually other sources will be required.

:

Russian   More aromatic, which brings out the fruit. Higher levels of    vanillin but harsher and more drying on the finish.

Creamy vanilla with more coconut flavours. Softer tannins .

    Smooth and subtle

      Vanillin flavours can be more astringent than European Oaks.

   High Tannins often used by North western Italian producers

    Fennel and liquorice notes

 Nutty and toasty.

Yes all that from the barrel .

 However then we also have

....lighter toasts emphasize the fruit while heavier toasting develops more smoky, woody, and spicy flavours.