Debemos is the first-person plural form of deber in the present tense.
It can mean:
The exact shade of meaning depends on context. In No debemos destruir el bosque, it can sound like either:
Debemos is:
That means the subject is we.
The full form would be:
Spanish often leaves out subject pronouns when they are already clear from the verb ending.
El bosque means the forest. It usually refers to:
Spanish often uses the definite article more than English does.
Compare:
So el bosque is the most natural choice if you mean the forest in a general or familiar sense.
No. They are different.
This is a very important difference.
The first means destruction is wrong or forbidden.
The second means there is no obligation to destroy it.
So they are not interchangeable.
In standard Spanish, especially in careful usage in Spain:
So:
In everyday speech, people do not always keep this distinction perfectly, but it is a useful rule to learn.
In your sentence, debemos destruir uses deber for obligation, which is exactly what you would expect.
Normally, no. In this sentence, the natural structure is:
That is because no usually negates the main conjugated verb, which here is debemos.
If you say debemos no destruir el bosque, it sounds unusual and marked. It may be understood, but it is not the normal way to say it.
So for ordinary Spanish, use:
A helpful approximation is:
The stress falls on the last syllable: -ir.
A few pronunciation notes:
So destruir is not like English destroy in sound, even though the meaning is related.
Yes, it could be plural, but the meaning would shift a bit.
Spanish can use the singular definite form to talk about something as a category or concept. So el bosque can sound like the forest as an environmental idea.
If you wanted to talk about forests more generally in the plural, you could also say:
Both are possible; the choice depends on what exactly you want to emphasize.
Not exactly. Grammatically, it is a statement in the present indicative, not an imperative command form.
It literally has the structure:
So it expresses:
It may feel like a command in meaning, but it is not built with the imperative.
For example, a direct command to a group would look different:
So your sentence is more like a statement about what we ought not to do.