I meant to add this to my previous post (see below) but my wife called me to dinner and I forgot about it.
In the late 80's, a friend of mine bought a large wooded lot at the south end of Ontario's cottage country so he could build his family a new home. The plan was, they would continue living in their existing home while he built the new one during his off-seasons. He is a boat builder and restorer, and a damned good one, so his off-season time became less and less each year, resulting in the house taking a far longer time to build than he had originally planned.
The first order of business was to fell a number of trees to clear an area large enough to build on and as the majority of the trees were poplars, he did so with the thought of harvesting lumber from them in mind. He used their heavy branches as spacers to stack the logs to dry. They sat that way for almost 4 years.
When the house was getting close to being inhabitable, he hired an acquaintance that owned a portable mill and they spent almost a week turning all the logs into workable lumber. Not knowing when he would get around to milling the lumber into trim, he stacked the boards with sticking so they would dry further. Sometime over the following year he ordered custom knives with trim profiles to fit his planer and ran some test pieces. At this point, the lumber had been drying for about five years and, according to him, had a 16% moisture content.
Shortly after he ran the test trim, the county building inspector arrived to inspect some recently completed work. Somehow the conversation during that inspection turned to the trim material and my buddy explained what he was doing and showed the inspector the test samples. The inspector immediately told him that he couldn't use the lumber.
According to the National Building Code of Canada, all lumber used in construction must be graded and approved by Canadian Lumber Standards Accreditation Board. This includes all structural lumber and remanufactured lumber; remanufactured lumber meaning all non-structural lumber that is not in its original standard size, i.e.: trim. Anyone can call one of the many approved Lumber Grading Agencies and have them come out and inspect your self-harvested lumber, stamping it with the appropriate stamp if it passes and making it instantly usable. This is done, however, on your own dime and it ain't cheap. If I remember correctly, they quoted my buddy $5k to inspect his lumber pile.
As he had a bunch of money tied up in his pile of unusable lumber, he refrained from putting a match to the lot of it and he has been slowly using it up on the different projects he as done over the years.
Now you know why most of the trees that you see being cut down in your neighbourhood are turned into firewood.