Thus a tree from the state of Wisconsin or from the Cognac region will have a more gradual, softer effect on the wine, and a tree from the Amazon might have pores large enough to hide crocodiles. For example, the Limousin forest in France is famous for lending generous qualities of vanilla to Bordeaux wines, whereas the barrels produced from white oak in the Ozark mountains in Missouri have a certain spicy quality that is very desirable. The cooper decides whether to split or saw the wood into staves, with splitting being more time consuming and costly. It does seem to be the method of choice. Bending the stave by fire or steam - again the tradition of fire bending lends a dry sweet oak flavor and is preferred.
Toasting is an off shoot of the tradition of fire bending.
You can now order barrels with light, medium or heavy toast that compliment the qualities of the various wines. This is accomplished by heating the open barrel over a bed of oak coals. The difference in the finished wine is the degree of smoky toasty flavors. The bottom line of all this is that the vintner will pick his or her barrels to add specific flavors and elements to the wine, much as the chef will put spices and seasonings in a favorite dish. However, we still haven't figured out how to do a pre-timed bake, so we can go away for 18 months and come back to a perfect wine.