What characteristic of wood is essential for ensuring its suitability in aviation applications?

The characteristic that makes wood suitable for aviation applications is its durability and treatment quality. In aviation, materials must meet stringent requirements for strength-to-weight ratio, resistance to environmental factors, and longevity. Wood that has been properly treated can exhibit enhanced durability, protecting against moisture, pests, and other forms of degradation.

Moreover, specific treatments can improve the wood's structural integrity and weight-bearing capabilities, making it a reliable choice for various components, such as interior furnishings and certain airframe structures, provided they meet the necessary safety and performance standards. Durability ensures that the material can withstand the stresses and strains of flight, which is crucial in maintaining the safety and performance of an aircraft over time.

While other characteristics, such as cost and availability, are important for economic considerations, they do not directly impact the technical performance and safety aspects that are paramount in aviation applications.