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:
“But parents can be understanding and accept the more difficult stages as necessary times of growth for the child. Parents can appreciate the fact that these phases are not easy for the child to live through either; rapid growth times are hard on a child. Perhaps it’s a small comfort to know that the harder-to-live-with stages do alternate with the calmer times,so parents can count on getting periodic breaks.”
—Saf Lerman (20th century)
“Every individual necessarily labours to render the annual revenue of the society as great as he can. He generally, indeed, neither intends to promote the publick interest, nor knows how much he is promoting it.... He intends only his own gain, and he is in this, as in many other cases, led by an invisible hand to promote an end which was no part of his intention.”
—Adam Smith (1723–1790)