1) Yes, The Tree of Spirit is a very good resource.
2) You and Guillem both caught that. Any method of establishing sacred space is suitable for the commitment ceremonies -- John insisted that each student should use whatever ritual framework for this he or she preferred. I used the AODA solitary grove ritual, since that's the part of the tradition that I was focusing on at that time, and John thought that was a great idea.
Re: Tree of Spirit and Is a Druid Grove Acceptable for Minor Order Ceremonies of Commitment?
2) You and Guillem both caught that. Any method of establishing sacred space is suitable for the commitment ceremonies -- John insisted that each student should use whatever ritual framework for this he or she preferred. I used the AODA solitary grove ritual, since that's the part of the tradition that I was focusing on at that time, and John thought that was a great idea.