Bulk/wholesale source for Italian or Siberian Alder?

I need to plant a lot of alders, and I need them to be able to tolerate summer drought. According to my research, this leaves me with Italian (alnus cordata) and Siberian Alder (alnus hirstuta) as my two best options. I've been starting Italian Alders from seed, but I don't have the resources/facilities to start nearly as many as I will need. Unfortunately, I also haven't been able to find any wholesalers offering drought resistant alder species. So now I'm asking here, do any of you know of good sources? If you know of other appropriate species, I would also be interested in that info.

Thanks.

Have you checked your state tree nursery?

If you are in Oregon, there is a pdf catalog:

https://www.oregon.gov/ODA/programs/NurseryChristmasTree/Pages/Default.aspx

Hmm.. that webpage seems to be about state licensing of nurseries. I'm not seeing anything indicating that the state runs a tree nursery or listing any product that might be available. Am I missing something?