Your going to get different opinions on this from everyone. My opinion is a "bushcraft" knife is any fixed thicker bladed knife that has a 3 to 6 inch blade with a full tang. In other words, a strong, sharp blade that's not going to break with heavy use. It's a general idea of any knife that will do the job for your methods. Most hunting knives are designed to be used for gutting and skinning, not for building/starting fires or building shelters. There are hundreds of knives out there to do this type of work, try looking at survivalist threads for different knife revues.