And the tree can be moved.
Many years ago, we were faced with Dutch Elm Disease. One stand was found...and it appeared to be pretty healthy. Our local famed arborist treated them...and....voila....they all died. The arborist himself told the story at a "rather private" seminar I attended.
I found an Elm Beetle-resistant Ulmus Americana years ago on a customer’s property, and took every seedling the tree dropped, grew them on and gave away over 500 saplings (8-10ft) to re-populate the county. They had a natural genetic resistance to the virus. BTW, the “Dutch Elm Disease” was misnamed; the Dutch were helping us find a cure, which didn’t happen. But the disease was wrongly attributed to them. It was a European Elm bark beetle, from Asia.
http://en.wikipedia.org/wiki/Dutch_elm_disease