What does the synthetic oil tech tree do?

[teamgene]

Synthetic rubber could be used for some things, but in others the Germans still needed the real thing. If I recall correctly aircraft had the priority on real rubber stocks. (Sorry for my laziness,but I don't remember now where I read this in detail to research, perhaps Inside the third reich which I don't have anymore?)

 

[panzerzombie]

A certain amount of real rubber needed to be added to the styrol-butadien-rubber ( buna ) wich was obtained from Japan ( Submarines and blockade breakers).

Interesting is the fact that the same basic material ( ofc with further refined properties and production methods ) is still used today.