Steelman: How to protect beehives

By BRUCE STEELMAN

Bee hives are traditionally made from wood; and wood remains an excellent choice for this application. Strong, insulating, affordable, and a safe material for bees and the food they produce. The hive bodies are a significant investment for the beekeeper and they take a beating during use, so prolonging the useful life span of a wooden beehive is an important consideration.

There are two complementary approaches to enhancing the durability of a wooden beehive:
- Keep beehives dry. Wood rot is caused by fungi that require liquid water (even so-called 'dry rot'). Because hives are kept outside, they get rained on but this doesn't necessarily mean that the wood has to get or stay wet enough to support wood rot fungi.

Keeping good covers on the hives to shed the rain will help a lot, as will providing foundations to keep the hives off the wet ground. Wood in continuous ground contact will become consistently wet enough to support fungal growth in most areas. However, even above-ground water can get trapped where two pieces of wood meet. Maintaining an intact paint film over exposed wood surfaces can help shed the liquid water before it has a chance to be absorbed by the wood. This is especially important at joints in the construction. Placing the hives in the open will also help the wood to dry rapidly after wetting.

- Use rot-resistant wood. Some wood is naturally rot-resistant because it contains naturally occurring protective chemicals. Some species with naturally rot resistant wood include the cedars, cypress, redwood and white oak. White pine, a common choice for bee hives, is moderately rot resistant. It is important to note that it is only the heartwood portion (inner, dead core of a living tree) that may be rot resistant. The sapwood of any species is highly susceptible to rot and mold. In white pine, the sapwood is wide so it can be difficult to obtain lumber that is only heartwood.

Chemicals can be added to susceptible woods to make them rot-resistant. This 'treated' wood is commonly used for utility poles, railway ties and decking lumber. Different chemical mixtures are used for different applications and, until recently, one called copper naphthenate was used for beehives. Copper naphthenate is a non-restricted-use pesticide that is widely used for DIY and industrial applications however the label instructions for its use in beehives was recently removed, at the request of the EPA. The basis for this request is unclear, as the limited data available suggests its use in beehives was acceptable. Treated wood is still acceptable for foundations and other components that are not inhabited by the bees.

The use of paint to help shed liquid water was mentioned above. However, paint is not a substitute for using rot-resistant wood. Painted wood that is continuously exposed to liquid water will get wet enough to support fungi.
Wood rot, even in its initial stages, makes wood much weaker. Thus, taking steps to protect beehives against rot is an investment that can pay off in terms of hive bodies surviving for many more years than they would otherwise. In summary, use durable wood when possible, especially for the supports that touch the ground, and keep your hives 'high and dry' for long-lasting wooden beehives.