Hybrid growth model to predict height and volume growth in young Eucalyptus globulus plantations

A process-base site productivity model (P ROM OD) was hybridized with an empirical growth projection model (N ITG RO) developed for Eucalyptus nitens plantations. The subsequent hybrid growth model was used to predict the time course of height and volume growth in 16 plantations of E. globulus located in northern Tasmania, Australia. Growth in these plantations was constrained by temperature, water stress, waterlogging and poor site nutrition. With the help of a few simple, easily obtained site descriptors, P ROM OD was used to predict the site index for these sites. This site index was used to run N ITG RO. Comparison of predictions with observed height and volume growth indicated that height growth was predicted accurately, but that estimates of volume growth were biased. The bias in the estimates of volume growth may be the result of the application of a growth model developed for E. nitens plantations to E. globulus plantations.