On the main version of the game, when you chopped one of the trees at the side of a beggar camp, you lost it on the next day. In this NorseLand expansion, it does not happen that way. The camp will not generate more beggars but, you will be able to convert into a Citizen House spending coin (5 coins). Once you start to build you'll unlock it.
Keep in mind the house will generate people from time to time and if it is outside your camp, you will expose the new people to the greed.
As SweetArchane mentioned, you do not need to play in Norselands to get this. This seems to be a modification of the core game that can be done on any of the scenarios.