Here’s what I’m trying with my first year trees in compost socks. Will probably put the 2nd and 3rd year trees in a similar configuration.
Laid down, socks on top of trunks to keep the wood at the bottom, 2 layers thick, only broke one 
Boards across the top to keep cover from touching the roots.
Covered with 6ft. ground cover, held down with compost socks that had annuals or failed cuttings in them. Will probably add a 2nd layer with more boards in between for some insulation after Thanksgiving.
It was pretty easy, about 1.5 hours to do ~60 socks. Not pretty but should get the job done.