My informant for this piece is an American of Scandinavian descent. He lived in Norway for a time during high school and learned the language while he was there. He also still keeps in contact with his host family from his time living there, and his son recently spent a year abroad there as well. In regards to this particular piece, it was said in old Norwegian culture that trees represent life, and each tree has a separate spirit.
After my informant moved into his house, he built a barn to operate his business from. When the barn was finished, the wetting tree tradition took place.
“Traditionally, an evergreen bough is nailed into the final beam of a barn–the ridge beam. When the whole building is done, a party is thrown and everybody drinks a toast to honor all the trees that went into the structure and to wish it a good future. We used a live tree–an olive tree–in a pot. And when it was all done we took it and planted it in the row by the house.”
Personally, I like this tradition because those who have helped to construct the building show their gratitude towards the trees for providing the materials which them to build it. But when we take a look at this Scandinavian tradition, it looks like an instance of sympathetic magic. More specifically, I believe it’s a practice of homeopathic magic. In order to ensure the prosperity of the recently built barn, a bough–or in my informant’s case, a whole tree–is hung from the highest rafter of the barn. Thusly, a part of what the barn is made out of watches over the entire structure in order to protect it.