There used to be(would) a big tree in my neighbor's house

[keannu]

Is the reason why "would" can't be used for a past state that "would" can only denote actions, so it means "a big tree was one time and disappeared and later it was there, and disappeared, then third time,,fourth time, etc"?

ex)There used to be(would be(x)) a big tree in my neighbor's house.

[5jj]

Yes

[Raymott]

Is the reason why "would" can't be used for a past state that "would" can only denote actions, so it means "a big tree was one time and disappeared and later it was there, and disappeared, then third time,,fourth time, etc"?

ex)There used to be(would(x)) a big tree in my neighbor's house.

You can say, "When I got home from school, there would always be a glass of milk and some cookies waiting for me."

Why have you given "would" and "would(x)" as an alternative to "used to be"? Surely you mean "would be".

[keannu]

You can say, "When I got home from school, there would always be a glass of milk and some cookies waiting for me."

Why have you given "would" and "would(x)" as an alternative to "used to be"? Surely you mean "would be".

My grammar book says past states can't be described by "would", but your example seems to be a habitual action not to mean a state, so it can be understood as a habitual action.

[Raymott]

My grammar book says past states can't be described by "would", but your example seems to be a habitual action not to mean a state, so it can be understood as a habitual action.

It can be described as an action, but no action is described.
Obviously someone is putting the milk and cookies there, but that isn't in the sentence.

[keannu]

It can be described as an action, but no action is described.
Obviously someone is putting the milk and cookies there, but that isn't in the sentence.

Seeing your example, I think it would be proper to say "would" is not for past habitual actions but past habitual events. and that's why it can't be used to describe a long-term state like "There used to be a big tree".

[emsr2d2]

Seeing your example, I think it would be proper to say "would" is not for past habitual actions but past habitual events. and that's why it can't be used to describe a long-term state like "There used to be a big tree".

You're right. You can't say "There would be a big tree" instead of "There used to be a big tree".

You might use "would" to describe a habitual observation about the tree.

Every time I saw the big tree, I would think it had grown another couple of inches.
Each time I drove past the big tree, I would utter an involuntary "Wow!"