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:

1 Ivy isn't a parasite and doesn't do the trees any harm, so leave it.

2 Ivy may not be a parasite but the weight of it is bad for the trees,
and it isn't doing them any good, so get rid of it.

My friends are now hardly on speaking terms. Who is right?