The message
from Eric L Drever contains these words:

I have just acquired a garden with some big, established trees. They
have a lot of ivy growing up them. I have asked friends whether I
should leave this or remove it, and so far have had two responses

Well, now I have had a lot of responses. Thanks to everyone who replied.
I will probably have to remove one of the trees anyway; otherwise I
shall trim the excessive areas of ivy, and keep watch on what lives in
the rest. Also, I may get some of the ivy broomrape!

Thanks again.
ELD