الطريق يدعى طريق الغابة.

Because the two words are doing different jobs.

• الطريق = the road. This is the subject of the sentence, so it appears as a normal definite noun with الـ.
• طريق الغابة is a name-like phrase in an iḍāfa construction: literally road of the forest.

In an iḍāfa:

• the first noun usually does not take الـ
• the whole phrase becomes definite because the second noun is definite

So:

• طريق غابة = a forest road / road of a forest
• طريق الغابة = the forest road or Forest Road as a name

That is why the second طريق is bare, even though the phrase is definite.

يدعى means is called or is named in this sentence.

So the structure is:

• الطريق = the road
• يدعى = is called
• طريق الغابة = Forest Road / the forest road

Altogether: الطريق يدعى طريق الغابة = The road is called Forest Road.

This verb is commonly used when giving the name of a person, place, or thing.

Here it is understood as passive in meaning: is called.

So although English uses is called, Arabic can express this with يدعى.

A learner may notice that without vowel marks, يدعى can look ambiguous in writing, but in this sentence the intended meaning is clearly:

• يُدعى = is called / is named

So you should understand it as a naming verb, not as something like calls.

Because Arabic does not always need a separate present-tense verb like English is.

In English, you say:

• The road is called Forest Road

In Arabic, the present-tense verb يدعى already carries the verbal meaning, so no extra word for is is needed.

This is very normal in Arabic. The verb itself is enough.

It is an iḍāfa phrase, often translated as the road of the forest or more naturally the forest road.

It has two parts:

• طريق = road
• الغابة = the forest

In Arabic, this kind of noun+noun combination is very common. The first noun is possessed, described, or linked by the second.

Examples of the same pattern:

• باب البيت = the door of the house
• مدير المدرسة = the principal of the school
• طريق الغابة = the road of the forest / forest road

Here it functions as the road’s name.

Because it has الـ, so it means the forest.

In an iḍāfa, if the second noun is definite, the whole phrase becomes definite. So:

• طريق غابة = a road of a forest
• طريق الغابة = the road of the forest / the forest road

Since this phrase is being used as a specific name, the definiteness makes sense.

It can be understood both ways depending on context.

Literally, it means:

• the road of the forest
• or more natural English: the forest road

But in this sentence, because it comes after يدعى (is called), it is very natural to take it as a name:

• The road is called Forest Road.

So grammatically it is an iḍāfa phrase, but semantically it works like a proper name here.

Yes, that can also be possible, and it means something like:

• The name of the road is Forest Road.

That sentence uses a different structure:

• اسم الطريق = the name of the road
• طريق الغابة = Forest Road

Your original sentence uses a verb:

• الطريق يدعى طريق الغابة = The road is called Forest Road.

Both are understandable, but the version with يدعى focuses more directly on naming.

A careful pronunciation would be approximately:

aṭ-ṭarīqu yudʿā ṭarīqa l-ghābah

A few helpful notes:

• الطريق is pronounced aṭ-ṭarīq, not al-ṭarīq, because ط is a sun letter, so the l of الـ assimilates.
• يدعى is pronounced roughly yudʿā.
• طريق الغابة is ṭarīq al-ghābah, though in connected speech you may hear it flow together smoothly.

If the full case endings are pronounced, it would be something like:

aṭ-ṭarīqu yudʿā ṭarīqa l-ghābati

But in pause, learners often hear:

aṭ-ṭarīq yudʿā ṭarīq al-ghāba

In fully inflected Arabic, the second طريق is the object or complement after يدعى, so in formal pronunciation it can appear with an accusative ending:

• طريقَ الغابةِ

So a fully vowelled version may be:

الطريقُ يُدعى طريقَ الغابةِ

However, in most everyday reading aloud, especially for learners, these final case endings are often not emphasized. That is why you may simply see and hear:

الطريق يدعى طريق الغابة

without worrying too much about the final short vowels at first.

In normal context, no. Here it is understood as is called.

The spelling يدعى without vowel marks can sometimes make learners wonder about other roots or meanings, but in this sentence the structure strongly points to naming:

• thing being named: الطريق
• naming verb: يدعى
• name: طريق الغابة

So the natural reading is definitely:

The road is called Forest Road.