爱护 is verb meaning "to take good care of". What sort of things can you take care of? Oh, yknow public places, things you use that are also used by others, and I suppose children and "later generations" in the more abstract sense, the more "cherish" or "treasure" sense, but god knows there's about 50 other and better ways to say that with regards to the "children". 保护 should be thought of almost exclusively as "protect".
Easy, we're done here.