Southern Yellow Pine, Douglas Fir, Cypress, Glulams and Reclaimed Timbers are good choices for Structural trusses. The strength characteristics of these materials fall in a similar range, and generally work as equal alternatives for similar spans, roof loads and member sizes. Glulams of equal size are generally superior from a structural standpoint. For Reclaimed Timbers, one must consider the species and condition of the material when evaluating for structural integrity.
Western Red Cedar and Cypress are known for their natural resistance to insect or moisture-related decay over time. Whereas Cypress has good strength characteristics, Western Red Cedar lacks the strength of the other materials above. If member sizes are large enough, there are circumstances where Western Red Cedar is acceptable from a structural standpoint. What Western Red Cedar lacks in strength, it makes up for in appearance. Western Red Cedar is frequently the material of choice for pure Decorative trusses, but should be checked thoroughly if intended for use in Structural applications.
Cypress is one of the most versatile timbers available for use in exterior applications. It is visually attractive (light in color with small knots), has good strength properties, and is resistant to both insects and moist environments. The shortcomings of Cypress are its slight price premium and more limited availability or longer lead times.