How well is that going to work in CA where the big problem is just finding water at the moment? We won't talk about all of the incidence recently where millions of gallons were released like at UCLA (Uggh!).
Actually having been to a couple of wild-land fires with what was then called CDF in an auxiliary capacity I do have some knowledge of the process. The reality is that just plain H2O is used as often as retardant, and that all kinds of aircraft are put in to service for air-drops.
The big thing about the DC-10 is carries a lot of H2O! It is also going to be limited as to what areas it can drop in. CA is a hilly place and there are some terrain features where it wouldn't be safe to take such a large aircraft. We also have copters and smaller fixed wing aircraft in use. They all play a part.