1) Regarding not covering the center post: I recommend covering it with sisal or wrapping it with rope, since kitty likes to stand on the high leaves & scratch the trunk.

2) In retrospect, the sisal rug is more work and $$ than wrapping with sisal rope.

3) You could probably stain either covering with a nontoxic dye if you wanted it a different color. Maybe: boil a length of sisal rope in a big pot of clothing dye and wrap that around the post?

I wish I had a photo of the post in my soho loft (16 foot ceilings) before I truncated it to fit in my brooklyn apt – it was 6 feet taller & had 3 more leaves.

Thanks for publicizing the project. My cat loved this & every kitty owner should build one!