Actually the cost of wood is nothing. There are plenty of agro industrial forests of tall, straight, fast growing pine down here. You see them tightly packed in rows. Totally unnatural compared to a real forest. At the mill the trees are squared off and we get the outer bark usually accompanied by a equal or more section of wood. It is scrap to them. They want it gone before it gets buggy. Chainsawed into thirds. The bark usually drops off and we have a nice board, flat on the cut side, with the rounded outer part of the tree on the other. With the rounded side you can stack them so you get airflow to dry them out.
When we are firing a really dry load we've done it in 9 -10 hours. Wet loads have taken 16 - 17 hours.