Media for tree storage

Burnt Ridge Orchards in WA keeps their nursery stock, largely exposed, in alder sawdust for easy transplantation and stress-free storage.

Has anyone experimented with keeping trees out in the open, in trenches in different media?

I know I could easily get a quantity of peat moss from a local supplier, but I don't know how it would compare to the officially-approved alder sawdust, which has to be delivered from further. And I don't know what I would do with the peat moss to do penance for the devilment that arises from using peat moss.  

Are they bare root trees that they are just keeping in sawdust until they sell in spring?  Or are they living in the sawdust through the summer?

I wonder if alder is critical or if any sawdust would work?

Reminds me of a Missouri gravel bed a little bit. I don't think I've seen trees growing in only saw dust though. Hugelkulture and soil with a ton of fluffy organic matter, or very sandy soil, I've seen - being very well drained is probably a key quality of baby tree growing medium

I have put bare root trees in trenches with wet newspaper covering their roots. If their roots get dry, they tend to die.

Mike -- keeping them until ready to plant out or sell. They could be in there up to a year. The idea being that if they grow any, it's minimally traumatizing to uproot them. I'm sure you would want, at the very least, a deciduous sawdust. I'm supposing alder is great because of its high nitrogen and quick rotting. Burnt Ridge said they buy 40 cubic yards at a time, yikes.

R Spencer, what's a MO gravel bed? And i thought growing trees on hugels was a bad idea?

Travis, were your wet newspaper trenches in the sun? I have had experiences such that I'm reluctant to rely on newspaper any more. Too hard to tell quickly by eye if things are drying out.