This is brilliantly designed to foster child engagement. Because we were doing this in story time, I gave the kids "magic telepathy powers" and gave some demonstrations on how to use them. This allowed everyone to engage with every interactive element of the book without needing to crowd in  or pass the book around (we've had issues with book damage due to this in the past.). The technique worked great! The kids were incredibly engaged, and seemed to display genuine wonder as their actions changed the tree.