Is this English sentence unambiguous?

[Kenny同志]

The sled is not fixed as is the case with the trees.

Is this sentence unambiguous? I have the feeling that it can be interpreted in two ways. That is, both the sled and the trees are not fixed, or that the sled is not fixed, but the trees are?

If the sentence is ambiguous, can it become definite if rephrased this way:

The sled is not fixed, as is the case with the trees.

Thanks in advance.

[anonymoose]

Yes, it's ambiguous, and I think adding the comma doesn't change this.

[Kenny同志]

Thanks for your prompt reply. Really fast!

[889]

That construction works only if both elements are positive:

Jane is American, as is Tom.

But not when the main clause is negative:

Jane isn't American, as is Tom. [so ambiguous, it's nonsense.]

Make it either:

Jane isn't American, nor is Tom. or Jane isn't American, but Tom is.

[Kenny同志]

Thank you, 889. nice tip.

[abcdefg]

The sled is not fixed as is the case with the trees.

"The sled is not fixed, unlike the trees." This would get the job done.

[Kenny同志]

good idea.