Wow! This is gorgeous. Notice how it is created, the top is flush with the wall and the bottom stands out - just how a picture frame would be if you leaned it against the wall. This uses the ladder type idea.
Book tree - functional art! ... cool feature wall for the library/ study/ storage room just off our main entrance - could see this feature wall through the double glass doors ... maybe attach or embed miniature lights along the wood branches so would twinkle the tree shape at night :)