A quick look through 'folk' in my iTunes library brings up these people/groups (excluding others mentioned above):

Bob Forrester on VotP V5
The Douglas Firs - track Woman of Wood, album Fatea autumn09
Harry Cox VotP 12 (tenuous = apple tree)
Ian Woods/Charley Yarwood on Seasons,Ceremonies & Riturals
The Lone Tree Orchestra on They All Died at Passchendale
Megan Henwood & Joe Henwood
The Sawdust Band on The Guv'nor Ashley Hutchings Volume 2
Trees

Lots of tracks & albums but June Tabor's At The Wood's Heart sprang immediately to mind.