Karl Marx writes in his book "capital", that the exchange value of a commodity is determined by the necessary average labor required to produce the commodity. The labor is measured in time.
Here's my question. There are different types of wood for the production of furniture. Why is furniture made of high-quality wood usually more expensive, while the amount of labor (measured in time) is independent of the wood quality? According to Marx, a table made of low-quality wood should be as expensive as a table made of high-quality wood (apart from negligible differences in the processing due to the wood quality). But this is obviously wrong.
What would Marx answer to this question?