Well Tony, you can always grow your own but that's something to start when one is young. If I were to start some walnut trees now, I doubt I would live to harvest them, much less be able to harvest them.

Just remember, the piers for London Bridge were made from English Elm, and they lasted 500 years. And if someone wants to make a camera from Elm, power to them (ie-one of the most difficult to work).