growth ring, in a cross section of the stem of a woody plant, the increment of wood added during a single growth period. In temperate regions the growth period is usually one year, in which case the growth ring may be called an “annual ring.” In tropical regions, growth rings may not be discernible or are not annual. Even in temperate regions, growth rings are occasionally missing, and a second, or “false,” ring may be deposited during a single year—for example, following insect defoliation…