Growing up, I was always told by my father and Grandfather that if a person uses wood (or other resources on their land) for their own use, it is not wasteful. I believe that strongly. I made hand hewn beams in my house out of spruce ironically enough, and honestly the slabs I was knocking off was substantial because I was doing it by hand. BUT those beams are in my own house. Sure I could have got a few more boards running them through the sawmill, but I wanted hand hewn beams in my house, not sawn ones. It was wood well used. In terms of firewood, using your own wood, no matter what it is for a species, is a good use of wood. Your are providing for your family. That is admirable for you and your land.