My neighbour has a majestic walnut tree and he has been kind enough to allow
me to try to take cuttings for bonsai stock. Does anyone know the best time
of year and what age of wood for cuttings? How well does air-layering work
on a walnut tree?

It's late autumn entering winter down here is the lower part of OZ, and the
tree is beginning to loose some of its leaves.

Lee
Tasmania