Which types of wood are considered decay resistant according to the provided information?

Wood species that are considered decay resistant typically possess natural oils or compounds that help them resist moisture and decay caused by fungi and other organisms. Redwood and cedar, for example, contain tannins and oils that significantly enhance their durability and resistance to rot, making them excellent choices for outdoor applications. Black locust is known for its exceptional durability, and black walnut is also recognized for its resistance to decay due to its density and natural chemical protection.

These characteristics make the mentioned species suitable for constructions in coastal and floodplain areas, where exposure to moisture can accelerate deterioration. In contrast, the other options include species that generally lack the same level of natural decay resistance and are more susceptible to rot and environmental damage when exposed to moisture over time.