Leon

I would’ve thought there were at least lingonberries over there? Lingon preserves have been around and ubiquitous enough since at least around the 1600s here in Sweden. In addition to that, off the top of my head there’s also blueberries, juniper, and at some point rose hips were introduced. Depending on where you are you could harvest cloudberries. In late spring/early summer you could harvest pine needles, as well as young pine cones.

In some part of China (Yunnan I think, but I could be wrong) they also harvest pine pollen, though I’ve not heard of that practise around here.

Granted, the ecology is decently different between Sweden and Norway, if they actually lived on a hunk of rock with no forest in sight I’d assume it’d be hard to get berries.