Douelles. Explanation below

As it is translating « L'oxygène passe à travers les douelles de bois » "Oxygen passes through the wood(en) staves" would fit, but the original author is definitely making the point that it goes through the staves made of wood (doesn't specify that they are French oak, which is most likely the case for Beaujolais). "Staves" appears to be a more direct translation of « douelles», but as these are both fairly technical terms it is possible the translator thought wood(en) curves would be understood better by more readers, or not!