Abstract: A time-dependent Markov model was developed to predict diameter growth of mountain ash(Eucalyptus regnans F.Muell) plantations. Themodel was established using data from a Nelder espacement trial. Thecomponents of diameter growth was based on multinomial logit regression using two-stage generalized least square procedures: The first stage comprising regressions of diameter transition probabilities against logarithm on stocking and age for each diameter class and the second relating the first stagecoeficients to diameter. Comparisons between this model and conventionalmethods (variously Normal, Weibull and Sb distributions) were made and it was showed that the time-dependent Markov model was markedly acclurater than the others. This time-dependent Markov model could be used to predict diameter growth for plantations with site index range 28-44m.

Key words: Markov process, Diameter growth, Paramrter estimation, Multinomial logit, Generalized least squares