They are associated with the early European Chalet culture, where it was presumably used to intimidate predators, frighten supernatural enemies, and convene council meetings.
The neverlur, as a natural horn, thus has no fingerholes or valves. Normally, a player can play 10 tones from the natural scale on the instrument. In the modern era, the neverlur is primarily a cultural curiosity, used for the occasional fanfare.
Source: Birch trumpet – Wikipedia