Modeling Individual-Tree Growth from Data with Highly Irregular Measurement Intervals

Bethesda

Society of American Foresters

2006

6 Abb., 4 Tab., 42 Lit. Ang.

Artikel aus einer ZeitschriftUnselbständiges Werk

7380

200137494

Fitting annual tree growth and survival models to data with irregular measurement intervals requires special consideration to the interpolation of the independent variables. This study presents an iterative method for continuously updating individual-tree and stand attributes, using the hypothesized functional form of a system of forward difference equations. Based on data from permanent sample plots, parameter estimates were obtained for three first-order difference equations of diameter and height growth and mortality for European beech in Denmark. One parameter of the individual-tree diameter and height growth models was estimated locally and expresses apparent site quality. The plot-specific parameters of the individual-tree growth models were highly correlated with site index and plot-specific estimates of rate constants from a dominant height growth model. Parameter estimates of individual-tree models based on either of those indicators of site quality allow for a flexible use of the models. The study failed to establish any relation between plot-specific rate constants and soil texture variables. The resulting system of individual-tree models is consistent with tree growth and mortality expected for beech in Denmark.