Elm trees are still around. They were not completely wiped out like the Chestnut tree was when the chestnut blight hit 80 years ago, although I did read recently of a few isolated, large chestnut trees that have survived because they are in a sense an island in a big sea and the blight never reached them. The champion elm tree here in Massachusetts is pretty impressive and is being treated with chemicals to avoid it being infected, and some elms have proven to be resistent to dutch elm disease, although the vast majority are killed before they grow into large shade trees. I think Princeton still has an area on the campus with some pretty large elms. I had a few die on my property a couple of years ago that were probably 20-30 years old, and I have seen 50 year old elms in my area.
Back in the pioneering days of the Iodine forum V always recommended that I have an Iodine loading test done to check my levels before I started any type of protocol. There is no one magic bullet to health and solving health problems. People are free to follow whatever protocol they chose.