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Forest Growth and Yield Models Viewed From a Different Perspective

Informally Refereed

Abstract

Typically, when different forms of growth and yield models are considered, they are grouped into convenient discrete classes. As a heuristic device, I chose to use a contrasting perspective, that all growth and yield models are diameter distribution models that merely differ in regard to which diameter distribution is employed and how the distribution is projected to future conditions. I describe different diameter distributions, whether they are the classical contmuous diameter distributions, the implied distributions of whole-stand models, or the discrete diameter distributions of size-class or individual tree models. There are also intermediates between these types of diameter distributions. Aggregation vs. disaggregation describes the alternate poles for how diameter distributions can be projected to future conditions. There are intermediates between these extremes, as well. There are several alternatives that vary from the classical paradigms. One alternative is a continuous analog to stand table projection that employs a "distribution modifying function" to project diameter distributions in time. One discrete variant of stand table projection is termed "non-naWe" size class models, as they relax one or more of the assumptions of size class models. An "individual tree kernel" model is one that uses a simple kernel function to distribute probability around an individual tree, rather than concentrate the probability at the measured diameter, as in typical individual tree models. Other variants are mentioned. These variants suggest that there is an infiite universe of alternative growth and yield models, and the classic labels for types of growth and yield models do not embrace these alternatives.

Citation

Goelz, Jeffery C. 2002. Forest Growth and Yield Models Viewed From a Different Perspective. Math, Modeling and Sci. Comuting. 13(3-4): 177-189.
https://www.fs.usda.gov/research/treesearch/7050