That sign was spotted in a Shizuoka suburb and shows how trees can be effective as wave breaks in the event of a tsunami. It looks odd – especially given the subject matter – but it’s apparently quite common for signage in Japan to feature cute characters like this:
This may sound counterintuitive or even a little condescending at first, but when you start thinking about it, it makes perfect sense. Whereas, say, photos of damage or devastation would probably cause people to avert their eyes, this sort of presentation lures people into actually reading the sign — particularly children, as tsunami education needs to start early.
Tsunami Characters [AltJapan]