If I say this sentence, would it be meaningful?
Similarly, trees can be described by neighborhood relations which we can see how trees exist with other objects in reality
Actually what I want to say is: trees can be described using neighborhood relations that they make with other objects in their vicinity.
No, it's not grammatical. The relative clause isn't formed right.
What you appear to mean is something like the grammatical relative clause
... neighborhood relations which allow us to see how trees ...
(parenthetically, this relative clause could be pronounced as either restrictive or non-restrictive; insert a comma before which in writing it, if it's intended to be non-restrictive)
In this relative clause, which is coreferential to relations, and which is also the subject of allow in the relative clause; us, on the other hand, is the subject of the infinitive to see in the complement clause that is the direct object of allow. This sorts out the relations in logical form.
The relative clause in your sentence, however, collapses the two concepts of allowing and perceiving into one clause with a complex verb phrase can see how trees ...
with we as the subject of the verb phrase. But what's which doing?
Nothing is left for which to refer to. Hence it's not a relative clause, since there has to be some noun phrase coreferential to the antecedent in a relative clause. So it's ungrammatical.
Not really. For your example, I would not use 'which' at all. An alternative might be this:
Similarly, trees can be described by comparison with nearby objects.
although it is difficult to know without the context.
