California is home to several species of termites — most notably the Western subterranean termite and the Pacific dampwood termite — that cause hundreds of millions of dollars in damage to wood structures every year. For builders and homeowners, choosing wood species with natural termite resistance is one of the most effective long-term defenses against infestation.
Why Some Wood Species Resist Termites
Termites do not eat wood for nutrition in the way that most animals eat food. They digest cellulose with the help of microorganisms living in their guts. Anything in the wood that interferes with cellulose digestion or with the termites themselves can deter feeding.
Naturally resistant wood species typically contain one or more of the following:
- High concentrations of extractives — Tannins, oils, resins, and other chemical compounds that make the wood unpalatable or toxic to termites.
- Dense, tightly grained structure — Hard, dense wood is mechanically difficult for termites to chew through.
- Low moisture absorption — Termites prefer wood with elevated moisture content; species that resist moisture uptake are less attractive.
Top Termite-Resistant Species
Coast Redwood (Sequoia sempervirens)
Old-growth heartwood Redwood is one of the most termite-resistant woods native to California. Its high tannin content, combined with characteristic acidic compounds, makes it strongly distasteful to termites. The U.S. Forest Service classifies old-growth Redwood heartwood as "very durable" — the highest rating for natural decay and insect resistance.
Note that Redwood sapwood (the lighter outer wood) is not termite resistant. The dense, dark heartwood is what carries the protective qualities. Reclaimed Redwood from old water tanks, wine vats, and Pacific Coast buildings is often nearly all heartwood, making it an excellent choice for termite-prone applications.
Western Red Cedar (Thuja plicata)
Western Red Cedar contains thujaplicins, naturally occurring compounds that resist both fungi and insects. Like Redwood, the heartwood is significantly more resistant than the sapwood. Cedar's distinctive aroma comes from these same compounds.
Cedar is widely used for fencing, siding, and outdoor furniture in termite-prone areas. Reclaimed Cedar, while less common than reclaimed Redwood and Douglas Fir, occasionally appears in California salvage yards.
Black Locust (Robinia pseudoacacia)
Black Locust is not native to California but is sometimes available in reclaimed inventories. Its heartwood is exceptionally dense and contains compounds that strongly resist both decay fungi and termites. Black Locust is rated "very durable" and is excellent for outdoor structural applications.
Old-Growth Douglas Fir (Pseudotsuga menziesii)
Douglas Fir is moderately resistant to termites — not as resistant as Redwood or Cedar, but better than most species. Old-growth Douglas Fir, with its dense growth rings and high heartwood content, is more resistant than second-growth Douglas Fir. The species is widely available through reclamation and serves well in protected applications.
Teak (Tectona grandis)
Tropical teak contains natural oils that strongly deter termites and resist water damage. Reclaimed teak, often sourced from old furniture, ship decking, and tropical buildings, is highly valued for both indoor and outdoor applications. Cost is high, but the longevity is exceptional.
Species to Avoid in Termite-Prone Areas
Some species are particularly vulnerable to termite damage and should be avoided in exposed or unprotected applications:
- Pine (most species) — Soft, low in extractives, and highly attractive to termites unless treated.
- Spruce — Similar concerns to pine.
- Hemlock — Generally not durable; not recommended where termites are a concern.
- Aspen and Cottonwood — Soft, low-density, and vulnerable.
- Sapwood of any species — Even durable species have non-durable sapwood.
These species can still be used, but require chemical treatment, careful detailing to prevent moisture access, or protection by more durable materials.
Why Reclaimed Wood Offers Advantages
Reclaimed lumber from old California buildings offers several termite-related advantages:
- Higher heartwood content — Old-growth trees produced lumber with much higher heartwood ratios than today's plantation-grown wood.
- Higher density — Old-growth wood is denser and harder than second-growth wood of the same species, making it mechanically more resistant.
- Demonstrated durability — Lumber that has survived decades in a building has already proven its resistance to local termite pressures.
- Aged extractives — In some species, wood extractives become more concentrated and effective as the wood ages.
Beyond Species Selection
Choosing a termite-resistant species is only one part of an effective defense. Other strategies include:
- Maintain dry conditions — Termites need moisture. Address leaks, improve drainage, and keep wood elements separated from soil.
- Use proper detailing — Maintain clearances between wood and soil. Use metal flashings and termite shields.
- Inspect regularly — Annual inspections by a qualified pest control professional can catch infestations early.
- Consider chemical treatments — In severe-pressure areas, chemically treated wood may be appropriate even when using durable species.
- Use physical barriers — Termite shields, sand barriers, and mesh systems can complement species selection.
Reclaimed Lumber for Termite-Prone Projects
If you are building or renovating in a termite-prone area of California, consider reclaimed Redwood or Douglas Fir for any wood elements that will be exposed to soil contact, moisture, or unprotected outdoor conditions. Our team can help you identify reclaimed lumber that combines high heartwood content, dense growth, and proven durability — giving your project the best possible defense against California's wood-eating pests.