The strong, unmistakable aroma of cedar wood has long been associated with repelling insects, a natural defense mechanism that makes it highly valued for storage and construction. This common understanding raises a direct question for those concerned with pollinators: is this same wood safe for bees, or does its scent act as a deterrent? The relationship between bees and cedar is more nuanced than a simple attraction or repulsion, depending on the specific type of cedar and the age of the wood. This information focuses primarily on the honey bee and common solitary nesting bees, such as mason bees, which frequently encounter this material in beekeeping equipment and nesting boxes.
The Volatile Compounds in Cedar Wood
Cedar’s protective properties stem from its heartwood, which is rich in volatile organic compounds (VOCs) and essential oils. These compounds are naturally produced by the tree and act as a defense against pests and fungal decay. The distinct odor is a powerful chemical signal in the insect world.
The primary insect-repelling components vary by species, but often include sesquiterpenes like cedrol and cedrene, thujone, and thujaplicins. These chemicals interfere with the sensory systems of many common pests, such as moths, termites, and carpet beetles. For smaller insects, these volatile oils can disrupt nervous and respiratory functions, acting as a contact toxin or vapor repellent. This chemical defense allows cedar to resist rot and remain durable.
How Bees Respond to Cedar Scents
Despite the repellent nature of cedar’s oils toward many insects, bees exhibit a high degree of tolerance, especially once the wood has been processed and cured. Honey bees perceive their world largely through their antennae, which contain olfactory receptors. However, the concentration of volatile compounds released by cured cedar lumber does not register as a significant threat to a bee colony.
Scientific studies testing honey bee colonies housed in cedar boxes found no measurable negative impacts on colony health. Metrics such as overwintering survival rates, adult bee populations, and brood area were identical to colonies housed in standard pine boxes. This tolerance is supported by the natural world, where feral honey bee colonies are often found nesting successfully inside hollow Western Red Cedar trees.
It is important to distinguish between the strong, localized scent of a highly aromatic cedar species, such as fresh Eastern Red Cedar, and the milder odor of cured lumber. While an extremely strong, fresh scent might be a temporary irritant, the long-term use of cured cedar wood does not deter or harm the bees. Bees prioritize a safe, dry, and stable cavity, and they adapt to the subtle, persistent scent of their wooden home.
Cedar Wood Use in Hives and Nesting Boxes
Cedar wood is a popular choice for constructing both commercial beehives and solitary bee nesting boxes, but the selection is based on its physical properties rather than any perceived attraction for the bees. Western Red Cedar is the most commonly used type for beekeeping due to its superior resistance to weather and decay without the need for chemical treatments. This longevity means the hive boxes will last for decades, providing a long-term home for the colony.
The wood also offers good natural insulation properties, which helps the honey bee colony regulate the temperature within the hive, a function that is extremely demanding of their energy. Furthermore, cedar is significantly lighter than other common construction woods like pine, which is a major logistical advantage for beekeepers who must regularly lift heavy hive bodies full of honey.
For solitary bee hotels, cedar is often chosen for the same reason—its durability and rot resistance ensure the nesting box will remain structurally sound for several seasons. When using new cedar, particularly for a hive, it is a common practice to allow the wood to air out for several weeks. This period of curing allows the most concentrated, highly volatile oils to dissipate, ensuring the environment is immediately welcoming for the incoming bee inhabitants.