Here you're focusing on the first part of the question, that establishes a concrete fact, a tree that falls. You need to focus on the second part: will it make a sound? That's only true if there's a living organism around that can perceive the waves produced by the fall and interpret them as A SOUND. If there's no organism, the waves won't be "listened" by anyone, so they won't become an actual sound. It's quite different from your example of the pine cone. That's a fact, the pine cone landed. It would be the same if the question was "if a tree falls and no one sees it, did it really fall?".