Ecological and mathematical considerations on self-thinning in even-aged pure stands

Ecological and mathematical considerations were made on Shinozaki's, Tadaki's and 3/2 power law models for the mean plant weight-density trajectory under self-thinning in even-aged pure stands, and interrelationships among these models were discussed. To overcome the discrepancy between the observed trajectory of the eastern white pine population and the one predicted from Tadaki's model, a new model was proposed. To construct the model the assumptions were made so as to incorporate the good properties of Tadaki's and Shinozaki's models in early stages of growth into those of the 3/2 power law model observed in later stages. Applicability of the model was tested for the pine population, which showed a good fit to the data. The growth analysis on the basis of the model revealed the growth curve of the pine followed a λw-type logistic cruve and suggested the existence of a lag time, a hyperbolic relationship between biological and physical time and a clear dependence of survivorship curves on initial density.