Yes because a dog, a cat or a bird might hear it and further the earth would "feel it" (important) so the event itself is taken place sound or no sound. The world moves on with or without us because we are just small components of the world. However the last part of the comment below is also true. I believe what is being said in the below comment is "don't ponder it, just live it". This is even better but sometimes pondering is what gets you there. Hope this helps a bit.
The tree will cause a disturbance in the air particles around it, sending out waves of sonic vibrations which could be defined as sound. The problem here is that the term "sound" refers to the translation of these sonic vibrations into a format our brains recognise. The sound is there in essence, it still exists, but it isn't there conceptually, as in something that can understood and defined, because there are no minds present to perform that action.
Take for instance, the tree that fell. If no people are around, is that tree a tree? No minds are present to give it that terminology, to apply the concept of what we as human beings understand to be a tree, to that tree. But the tree is still there in essence, it still has its physical form and for all intents and purposes, exists. It's just that there's no one around to identify it as a tree.
If there are no ears around, it wouldn't make a sound. It would just produce a wave through the air, but the sound is created in the ear (well, rather in the brain). Just like colours, they don't exist in nature per se; it's the eye and the brain what turn electromagnetic waves into colours.
Sound like all things, is based on perception. Theoretically, if no one were around to measure the noise it would not exist. however there are sentient beings capable of just that everywhere even if we are not present at the percise moment the tree falls the fact that we exist and know the nature of a tree in comparison with our own we know that trees fall often. With this realization comes the automatic, trees are tall, green, brown, ect. Of those realizations is that when trees fall you describe the process of falling based on the sound it makes and the initial *BOOM* that occurs when it touches the ground. This is a simultaneous experience. Meaning, the sound exist because you percieve it INTO existance whether your present to experience it or not, but can only experience it because it exists.
It makes sound waves, the definition of sound is a bit vague and in some the waves have to hit something that can hear them in order for it to be a sound. So yes or no depending on your definition of sound.
Does the event even occur when you do not witness it? This is the fundamental question here. Does the tree even fall, if you do not experience it? Does it "fell in the past" once you assume it did, by looking at the fallen log and contemplating its origin?
Also, when you wake up from a dream, and someone tells you that you have been asleep for a while, and you were tossing and turning as if you had a nightmare, have you had a bad sleep in the real world because present circumstances imply so?
Yes, it does make a sound. Even if you cannot hear it - there are many sounds at this moment. First of all: The sound of the fall. It makes a sound when the tree hits the earth's surface. Secondly, the sound of the tree itself as a tree is a plant and thus a living being. It can feel pain and other sorts of feelings as well it can share. So it hurts the tree when it falls and he will moan in form of a creaking or something. Thirdly the sound of vibration when an object hits another object. When the tree hits the earth, it is like bouncing till it comes to a rest. That spring-effect causes a dumb vibration. Fourth is a think of belief and as I believe in it, I am going to write about it. Everything in the universe is connected like a cosmic network. So everything is in a constant flow of harmony, working closely linked together. When one link in this chain is missing the flux will be disturbed. That you can rather feel instead of hearing. And the last possibility of sound, number 5: There are other plants (trees, perhaps moss, mushrooms, grass) or perhaps even animals around. They are living beings. And thus they will hear the frequency or even more of the fall.
In a physical way, yes, it produce sonar waves so it makes sound. But, a phenomena can be called as it because we can observe it, so even if it made a sound, it is as it didn't because no one can said it did.
I don't know much about science and physics but I think that when there's no 'receptive' like an ear or something around to hear the sound waves the falling tree makes then they are just silent sound waves because it's the systems in like our ears that turn vibrations in the air to sound.
The debate over this question arises from a simple equivocation of terms: does the word "sound" refer to the mechanical action of the propagation of waves through the medium of air, or the human experience of sound itself? Once you resolve that issue (by for example, substituting new terms for each) the problem goes away. It makes the former but not the latter. All are in agreement on this.
All trees make at least a small amount of sound when fallen. Whether sentient beings capable of hearing sound are there or not does not matter as to whether a fallen tree makes a sound. This assumes that the tree is in a medium capable of transmitting sound. If the tree is in a perfect vacuum it makes no sound.
Then, I suppose we'll have to assume all the dead trees laying around were put there in a semi-dessicated state by the hand of god at the moment immediately before they were observed? That is preposterous.