Which type of wood is most resistant to decay and commonly used for outdoor applications?

Cypress wood is well-known for its resistance to decay, making it an ideal choice for outdoor applications. Its natural oils and compounds, particularly cypressene, contribute to its durability against moisture and pests, which are significant factors in wood decay. This intrinsic property makes cypress a preferred material for outdoor structures such as decks, fences, and playground equipment, where exposure to the elements is a concern. In contrast, oak, pine, and birch do have their uses but are generally less effective at resisting decay when used outdoors without proper treatment or preservation.