Growth Functions

Abstract

Growth functions describe the change in size of an individual or population with time. Selection of appropriate growth functions is a critical step in quantifying forest stand dynamics, growth and yield. This chapter presents information on the forms and characteristics of growth functions that are widely used for modeling forest development (Lundqvist-Korf, Richards, and Hossfeld functions). Although, when fitted to data, a number of functions will give essentially equivalent results within the ranges of the observations used in parameter estimation, their behavior when extrapolated may be quite different depending on the underlying mathematical properties involved. Hence, understanding these properties is essential to determining which candidate functions to consider for specific applications. Important mathematical properties of growth functions commonly used in modeling forest growth and yield are described and also graphically illustrated.