I decided to photocopy the trunk so I could test out some designs before actually marking the wood itself.
Idea 1 - Is kind of an amalgamation of many ideas and doesn't really correlate with the notion of natures time as a cyclical, although I do really like the word timelessness and it is fitting that it has 12 letters. I think the roman numerals work a lot better than actual numbers as they feel more old fashioned or traditional and in keeping with nature, because it to has been around centuries ago.
Idea 2 - I really like the idea of an outward ever expanding spiral when thinking about time, as it sort of mimics what happens in previous cycles but is always evolving and changing. This is maybe a good design for a different time, but it doesn't really represent natures time all to well.
Idea 3 - Starting with the Roman numerals, it is similar to a clock, signifying that we are looking at time, the next layer out is the months, of which there are 12 (very handy), then I have added the seasons on the next layer and then finally we have the moon cycle on the outside. I really like this design and am going to continue with this one.