Very disturbing and ??? on fire

Watched the movie because I saw it had Michelle Yeoh and Sean Bean in it. Love both of them. The acting was very good, but as the movie went on, I got more and more restless and nervous. A credit to the moviemakers that they could actually set the barrenness, the darkness, the desperation to such a high point. I think two things are worth mentioning... (1) maybe the shaman was right when he said that the Michelle Yeoh character had an evil side to her personality. We sort of dismiss it as just "sorcery" or such, but doesn't the ending of the movie sort of support the fact? Yes, she is faced with a terrible future, if her adopted daughter up and departs with her new lover. But for things to go the way they did, that shows a major unbalance. Didn't the daughter actually say, "You can come with us?" Shows that she did have a bit of conscience and didn't just want to coldheartedly leave the older woman on her own. Understandable too that the older woman had once known love and wanted to experience it again, but heck... find another way. Share Sean Bean or ask him to drop you off way faraway where you can make a new identity and try to find a new life/love. But, it is all too much a part of her personality to believe she is unworthy and flawed. That fact has her more locked in than the ice. (2) Where do they get the wood for fires in the tent? I thought at first they were burning walrus blubber or something, but that would have caused horrid smoke. Plus, during a few scenes, they film the fire and it is actually wood that is burning. Thinking back on the scenes, even the vast panoramas, I don't think I saw one tree.