What dabs said. In fact, Durham's is a great all-around modeling item to have if you're doing any kind of diorama or scenic base at all. It can be mixed thick or thin and textured any number of ways while it's still wet. It cures like plaster of Paris, rather than drying; once hard you can work it almost like wood. It accepts pretty much every finish known to man.
One thing to watch out for: I learned from the example of a friend of mine that you DO NOT want to apply Durham's (or, I would guess, any other water-based product like plaster or Celluclay) to an unfinished wood surface. My buddy did so to one of those plaques that was cut from a section of a tree - you know, the ones with the bark around the edges. Overnight, the wood absorbed the moisture from the Durham's and warped so that the plaque was unusable. I have had no problems applying water-based materials to a wood surface that has been finished with a sealer like lacquer or polyurethane varnish.
BTW, the sequel to my friend's dilemma is, the plaque was going to support a Revellogram T-Rex from Jurassic Park. My pal panicked when he woke up to find his base ruined, then ran out and found a broken tree branch on which to perch his dino. He took first place in his category at the IPMS show we attended the following day.
