"Basset" wrote
Is this a good time to plant trees? . We were thinking fast growing trees
.... in the north east Scotland .. to protect from the wind. Leylandii?

I understand from talking to a tree expert years ago that Leylandii is not a
good windbreak tree as it suffers wind burn (especially if it gets any salt
spray) in exposed sites, may I suggest you contact the Forestry Commission
or similar for a suitable tree for your area.
Italian Alder is a good one down south but I don't know it's hardiness in
your area.

--
Regards
Bob
In Runnymede, 17 miles West of London