Will, All,
How about a twist on two of the options.
These could even run side by side, with two prize pools and one can either enter one or the other, or even both!
Phase 1. Photographic competition: - Preparation, Lighting and taking a picture of a tree. Perhaps a maximum of three pictures per entrant.
Could be 3 point, single tree on stand, tree on good base and backdrop etc...
The best individual photograph, not necessarily the best tree/display wins.
Phase 2. Virtual competition: - Taking any of the submissions in Phase 1 or any of your own, then providing a before shot - then one virtual of how you would re-style it, place in another pot or display environment etc....
The best transformation wins.
The beauty of this type of thing is actually using processes that many members will use in every day use here on the forum, or will certainly benefit from, by getting their teeth into it or practicing. Also, generally, no harm should come to any tree !
Just some ideas. . . . .
Ian.