You may recall some of the Pisces Moon Altar images from the Hermetic Library visual pool a little while back. Jacqueline Elaine Gomez, who posted those images to the group, is working on a project under the auspices of Church of Anthrax to encourage others to create their own tree altars.
You can check out her own personal Tree Altars photo set, and from there contact her directly if you want to find out more. Of course, you could just go ahead and make one either way. But, consider sharing some images of your altars with her project, and also with the Hermetic Library visual pool.
“The Church of Anthrax (or COA) is both a collective and an individual. Self and other reflecting ad infintum. COA is a religion as art performance collective founded by Jacqueline Elaine Gomez.” [via]