| Tree | English Name | Dates |
| Beth | Birch | December 24 - January 20 |
| Luis | Rowan | January 21 - February 17 |
| Nion | Ash | February 18 - March 17 |
| Fearn | Alder | March 18 - April 14 |
| Saille | Willow | April 15 - May 12 |
| Uath | Hawthorn | May 13 - June 9 |
| Duir | Oak | June 10 - July 7 |
| Tinne | Holly | July 8 - August 4 |
| Coll | Hazel | August 5 - September 1 |
| Muin | Vine | September 2 - September 29 |
| Gort | Ivy | September 30 - October 27 |
| Ngetal | Reed | October 28 - November 24 |
| Ruis | Elder | November 25 - December 22 |
December 23 is not rules by any tree, and is the proverbial "day" of the "year and day" in early British courts.