wanting to sell 4 fern trees

Advertise them . They are worth a lot of money, look in garden centres.

Like wyeboy says,advertise in your local paper,ask or look in your local garden centre for the prices for similar sized fern trees and go from there.
They are worth a lot of money each. Bren

G'day, Natante - Don't see many folks from all the way over in Oz on here! Me, Wyeboy and Bren are in the UK. Tree ferns over here are indeed worth a lot of money, but I would think they would be worth less in your part of the world, since tree ferns come from (I think) Tazmania, so they don't have to travel quite as far to end up in your garden! I think a garden centre/plant nursery/retailer might be prepared to buy them from you - especially the 7m one - huge! To research prices, have a look round a good garden centre, or what about looking on the E-bay site for your country? Although I don't know how one would get a 7m high tree fern in the post?! Good luck!

Sid, you are silly, you fold it up and put it in an envelope! But don't forget the stamp.

Thanks guys. Do any of you actually know what these trees are called?

Dicksonia Antartica I think is the name of them.

That's right, except it's spelt Dicksonia antarctica, for googling purposes!!! :-)