Omikuji, paper fortune
Question:
Why do they tie their paper fortune to the shelf??
Answer:
People tie their bad luck on it and Kannon Buddha takes care of it. In the past, people did on a branch of trees in the ground but it made tree damaged. That's why the temple set them here.
Pic: http://mokkei-entertainment.com/2012/06/08/omikuji-sugoroku/