I was called to remove bees from inside a pear tree last spring.What intrest me is there living conditions.Top entrance at about 7', old cut off limb.Bees traveled down 3' to a open area in trunk. about 9" dia. by 30" in length with walls about 8' thick. below this very soft roted wood very soft. easy could have been removed by bees to make a larger home. four combs none wider than about 8". so total hive not larger than one med super. total storage of maybe 25 or 30 pounds. tough winters here in Pa. I believe the heat from ground traveled up inside of tree and out top entrance.According to property owner bees had been there 4 years and swarmed once each year.so every year new Queen. Yet as a beekeeper we provide two full deeps of food and still can run out of food by spring.I am trying one 7 watt red light bulb in bottom of each hive this winter.From Dec 23 till spring to try to simulate this same concept in my colony's.just looking for others thoughts.
We as beekeepers also desire the most honey out of our colonies as possible, so we give them as much room as we can to let them grow. Honeybees in the wild are only looking for a suitable place to call home. I would dare guess that many hives in the wild are as small as the one you describe. We beeks try to provide them with 2 full deeps of honey going into winter, but we also had 2 full deeps of bees all summer long. Add to that, our hives that are mad of 3/4" thick wood (in most cases) have a far lower insulation value than that of a tree trunk. The better the hive is insulated, the less honey the bees will consume trying to keep it warm. I know that Robo has used bulbs in the bottom of his hives in the winter with much success... maybe he will pipe in!