I wondered the other day whether both of these words are adjectives.

Problem:
One of them looks more like an adjective than the other one does.

Explanation:
The primary definition of “wood” as an adjective is made of wood.

The primary definition of the adjective “wooden” is made of wood.

The secondary definition of “wood” as an adjective is wooden.

The secondary definition of the adjective “wooden” is wood.

In other words, “wood” as an adjective is interchangeable with “wooden”, despite the fact that “wooden” looks more like an adjective than does “wood” (which also is a noun).

Solution:
Don’t worry about which word to use as an adjective; they mean the same thing.