Plain-old pine is worth a lot less than good quality knotty pine for paneling projects. It takes additional skill and care in handling wood with knots and so construction with this wood is also more expensive. Diagram 16.11 is well done. That is not quite true. The wood shrinks very predictably, but it takes an expert to make the prediction accurately.
Most construction crews lack a botanist.
For example, Question 20 on page 380 seems to contradict what you read in the essay on page 376. Go back to the Course Schedule .