Ron,
Glad you mentioned this. DWM did their own wood processing and mainly used French walnut (from the southern part of France) as a base material.
Needless to say, the demand was larger than the supply and being at war with the French didn't help either.
Use of beech wood caused many problems, because it would tend to split, especially when used on rifle stocks.
(this is mentioned in the company's corporate history, 1939)