Forest stand dynamics and similarity theory

Data for modeling forest stand development require repeated, costly measurements over extended periods of time. The purpose of this study was to develop methods for generalizing short-term observations in juvenile stands to long-term trends in more mature stands. The concepts applied involve scale modeling techniques whereby small physical models (model system) provide insight into the nature of important phenomena (prototype system). Loblolly pine plantations in an operational spacing and in a scale that consisted of reducing the distance between plants to 1/16th that of the operational spacing were regarded as prototype and model systems, respectively. Stand development in these two forest systems was examined using principles from similarity theory. er to apply similarity theory, the temporal development of two commonly measured variables, height and diameter, were standardized on a common scale using data from prototype and model systems. Then, nondimensional height and diameter ratios in the two systems were created using appropriate reference variables from each system. Analysis showed that the height and diameter growth relationships developed similarly for the two systems making growth results from the model system scalable to the prototype system. Scaling functions for forest systems established at small spatial scales could be useful tools for a host of research and developmental purposes.