Standard Article

Age-Growth Modeling

Ecological Statistics

  1. K. Sagary Nokoe

Published Online: 15 JAN 2013

DOI: 10.1002/9780470057339.vaa010.pub2

Encyclopedia of Environmetrics

Encyclopedia of Environmetrics

How to Cite

Sagary Nokoe, K. 2013. Age-Growth Modeling . Encyclopedia of Environmetrics. 3.

Author Information

  1. Wisconsin International University College-Ghana, Accra, Ghana

Publication History

  1. Published Online: 15 JAN 2013


This section is on growth of nonhuman individuals. Growth of an individual or a group of organisms is generally defined as the change in dimensions over time. Growth rates vary between and within plant and animal species. They are generally influenced by both genetic and phenotypic factors, and may be negative or positive. Positive growth relates to increases in dimensions (weight, height, and number of component parts) over time, whereas decay or negative growth refers to the decline over time. Human interference, either intentionally or accidentally, environmental influences, and management practices can substantially influence the growth forms and patterns of individuals and population. Age-growth functions constitute important analytical tools in the management of natural resources. These models are explicit expressions of both theory and empirical knowledge, and are useful for growth and yield prediction and evaluation of alternative management strategies, among others. The approach to age-growth modeling may be based on either primary (single) unit or stand (aggregate of units). Irrespective of modeling philosophy, the goal is identification of the most parsimonious and biologically reasonable model that best describes the relationship between the response variable (which is a measure of growth) and time (age).


  • linear models;
  • differential equations;
  • repeated measures;
  • Markov chain models;
  • semiparametric;
  • fitting age models;
  • cross-validation