Many would answer: "a tree hollow." But how long can a single bee colony inhabit one hollow, and how large must it be for the answer to be at least one year? It turns out the tree must have a trunk at least 60 cm in diameter, and the cavity should be around 2 meters long. How many such trees do we have left? Even then, in natural conditions, bees will occupy such a hollow for only one or two years before abandoning it—once it becomes filled with combs, the old comb will create conditions for disease development.
The space will then be taken over by the wax moth (a unique insect and the only organism capable of digesting wax), which will destroy the old, dark combs. After a year or two, the hollow may be reinhabited. But how long can a tree with such a large hollow survive? It will likely break during the first strong storm, leaving an opening too large for bees to winter comfortably inside.
Therefore, the invention of movable combs by Langstroth—or what we now call the bee frame—can be compared to the discovery of penicillin. Just as penicillin saved countless lives, the movable frame revolutionized beekeeping, making it popular and commercial. It increased the number of bee colonies and introduced honeybees to regions where they were previously absent or where other species, such as Apis cerana (which store less honey), dominated.
This last point is not entirely positive, as it also led to the spread of new bee pests (as I have written about earlier). Following the movable frame, modular hive systems emerged, laying the groundwork for future discoveries in bee biology and genetics and enabling the transport of colonies over long distances.
Initially, hives were made of wood. But as the example of tree hollows shows, wood is a rather unstable material. Moreover, wooden hive production increases pressure on the timber industry, leading to deforestation, which is essential for maintaining the planet’s ecological balance. Additionally, the weight of a wooden hive with bees makes it difficult to move without special equipment.
Humanity, too, has long enjoyed the benefits of civilization, building homes from advanced, convenient materials.
For the reasons above—and because the author has extensive firsthand experience with medical-grade polyurethane foams—I would like to focus on the use of this material for hive construction. Its properties include chemical inertness, light weight, safety for animals, and, importantly, it is the best thermal insulation material known to humans.
Moreover, polyurethane foam hives are cheaper than their wooden counterparts and do not require logging for production. In medicine, polyurethane foams are used, for example, in intensive care units, where special materials made from it prevent bedsores in immobile patients.
Once cured, polyurethane foam has a surface hardness comparable to wood but weighs half as much. This makes beekeeping accessible to people with less physical strength, such as children and women.
If you still have doubts, consider that in Scandinavia and Northern Europe, foam hives have almost entirely replaced traditional wooden hives. Only in dry southern regions can classic wooden hives still be found.