I am an urban beekeeper with apiaries in Oslo, Norway. One of my apiaries is in the Royal garden in the center of Oslo. One day summer 2013 I got a call from the castle informing me that bees flew in and out of a tree close to a path in the garden. The entrance was about 2 meter up and they were a bit skeptic for the safety of visitors. We met up in front of the bee-tree (foto 1). The bees were very busy, heavy loaded with colorful pollen on their hind legs. I love this sight knowing that the pollen will be chewed and fed to the hungry babies. Very proud I told the castle representatives about the fairytale going on inside. I told them we could direct the bees flight upwards with a simple construction. They too got fascinated. However, after some intern discussions the castle said no. I called a friend to do the job (I could not do it) to suffocate them with gasoline - I am told that this is the least harmful way (foto 2). A cloth was soaked and stuffed in the entrance closing it totally. They died, tears.
But - the story goes on. I have checked the tree regularly since, and late may this summer, 2021, a new swarm had moved in. The castle representatives met up and I started again to promote the tree bees. This time I could add the wonder it is that this crevice, full of disaster, dead bees and bad fumes, has the eight years since 2013 been worked with by microorganisms to such an extent to make it livable again. Now the tree bees are welcome to stay. (film)