Periodic annual increment (PAI), is a forestry term that describes the change in the size of a tree between the beginning and ending of a growth period, divided by the number of years that was designated as the growing period (Avery, 339). For sigmoid growth, the graph of PAI increases rapidly and then quickly declines, approaching zero. PAI may go negative if a tree loses volume due to damage or disease. Periodic annual increment is commonly used instead of current annual increment as a basis for computing growth per cent. Growth per cent indicates the rate of increase with relation to the wood capital required for its production, this is usually based on a single year's growth (Chapman, 315).
Famous quotes containing the words periodic and/or annual:
“It can be demonstrated that the child’s contact with the real world is strengthened by his periodic excursions into fantasy. It becomes easier to tolerate the frustrations of the real world and to accede to the demands of reality if one can restore himself at intervals in a world where the deepest wishes can achieve imaginary gratification.”
—Selma H. Fraiberg (20th century)
“In soliciting donations from his flock, a preacher may promise eternal life in a celestial city whose streets are paved with gold, and that’s none of the law’s business. But if he promises an annual free stay in a luxury hotel on Earth, he’d better have the rooms available.”
—Unknown. Charlotte Observer (October 6, 1989)