The real world of moisture content control

I would like to start by making it perfectly clear that I am not an expert on lumber drying and its related problems. My entire experience in this field consists of one week of weighing kiln samples at one of Charlie Kozlik's kiln drying short courses at Oregon State. In fact, I sometimes question that there are any experts in this field, as we normally define an expert. The leaders in this field probably should be called the high priests or head witch doctors or some such term. I read somewhere that content is defined as the weight of water in a wood sample, expressed as a percentage of the oven-dry weight of the wood. Moisture content may vary from zero for oven-dry wood to over 100 percent when the water in the sample weighs more than the wood fiber. To a layman in the field of lumber drying, and I consider myself as such, it appears that this is the sum total of the exact knowledge and total agreement in the field of lumber drying. However, this is your image and your problem. My problem is that as a staff member of the West Coast Lumber Inspection Bureau, we are charged with the responsibility of measuring and enforcing moisture content regulations for lumber. I am reminded of a definition of the game of golf which is something to the effect that Golf is a futile attempt to put an insignificant ball into an obscure hole using inadequate tools. Moisture content measurement and control lends itself to a very similar definition. Drying lumber to the new moisture content requirements of the recently adopted lumber standards is not an easy task as many of our member mills have discovered. The handbooks tell us that freshly sawn lumber can have moisture contents that are very high. The average for Douglas fir is 37% in the heartwood and 115% in the sapwood. For hemlock, the figures are 85% and 170% respectively. These are average values. Some pieces of wood will go well over 200% in moisture content, particularly in hemlock. Lumbermen use many descriptive terms to describe these pieces, the most socially acceptable of which is sinkers. So lumber can be dry or green, or very green. It's all a matter of degree until you get to the American Softwood Lumber Standard PS 20-70 and then there is no degree anymore. It's either green or it's dry. PS 20-70 contains the following definition. . . DRY LUMBER For the purpose of this standard, dry lumber is defined as lumber which has been seasoned or dried to a moisture content of 19% or less. GREEN LUMBER For the purpose of this standard, green lumber is defined as lumber having a moisture content in excess of 19%. It's a go or no go proposition, and 19% is the magic figure. Since the standard is so explicit about what is green and what is dry, it would be nice if it were equally explicit in telling you how to measure a piece of lumber to determine if it is indeed green or dry. Unfortunately, all the standard says is Provisions for seasoned lumber shall be expressed in terms of maximum moisture content to be allowed at any point on each piece. Now this statement can be interpreted to mean that if you could find a spot or pocket in a piece that was over 19%, the piece could not be called dry. This of course is unrealistic because of the variation of moisture content within even a seasoned board. An interesting study was made some years ago on the distribution of moisture in a 16 foot 2x6 Douglas fir plank. The average of the entire piece