Tree hive with properties of the hollow tree
I have only one of these hives left in operation and will not put any more into operation. Therefore I will not publish a building instruction for this hive. The positive effects for the honey bees by a slim and high geometry can be obtained in my opinion also by a good external thermal insulation. The restrictions in the handling of the hive and in the inspection of the bee colony are so serious that I take distance from it in the future.
The geometry, buffer effect and thermal insulation of tree hollows are reproduced in this construction. One hive was equipped with several sensors for temperature and humidity for one year. The data confirm again the way bees reduce moisture.
With regard to the integration of book scorpions, it contains straw areas on the sides of the combs construction. These straw chambers are separated from the bee room by a wide meshed grid, which the bees can easily pass through. The straw is loosely filled, the bees can move and stay in this area. Small segments of wooden boards are bolted to the outer wall in the straw chambers. They serve as a retreat for the book scorpions. IR videos show that book scorpions approach resting bees with preference for parasite checking.
The geometry of the tree hive is based on that of hollow trees. Width x length of the chamber of the bees are 16 x 19cm, the height of the interior 105cm. The ratio of height to diameter is 6 and the bees have a volume of 32l for honeycomb construction. A recent study involving T. Seeley (see downloads) shows a positive influence of small hive volumes on the development of Varroa.
I decided for a construction of massive wooden planks (4,5cm) and an additional insulation of the upper half of the hive made of PUR insulation boards.