Wood Shingles
Most wood shingle and shake roofs are made from western redcedar (Thuja plicata) because of its exceptional properties, including defect-free straight grain, dimensional stability, low weight (low density), impenetrability to fluids, and—probably most important—decay resistance, derived from natural substances found within the wood.
Other wood species, notably redwood (Sequoia sempervirens) and and cypress (Taxodium distichum), have similar properties and are sometimes used; but decreasing supplies significantly restrict production and distribution. In addition, there’s limited distribution of other woods that have been impregnated with preservative chemicals either by pressure-treating (best) or dipping.