But the tree never makes a sound.

That depends on how you define 'sound'. If it's only perception and interpretation that creates sound, then sure, a tree falling with nothing to hear or perceive it makes no sound. But if you label sound as the vibration created independent of the perception of the phenomena, then sound happens regardless of whether it's perceived or not. Since we label some sounds as imperceptible, or outside of human hearing ranges, my interpretation would be that the phenomena is the sound, rather than the perception of it.