beech hedge

I’ve tried looking online and on the forum but its still quite confusing. General advice is airlayer after the new growth has hardened off. However I also hear/see people have air layered before then (ie February) and had success. Does anyone know which timing is best? Its still frosty here...

Hopefully this is the right subforum. I made a post in the ‘new to bonsai’ section and got some suggestions to try cuttings and air layering to propegate some local trees/plants whilst I wait on my seeds. I went and had a look at the beech hedge we have and took some pictures, these are just...

So I have the opportunity to collect as many of these European beeches as I like, they've been growing here for 60+ years. There's a couple in there with interesting trunks that would be worth having. However the problem comes as they need to be out of there by October and obviously the best...