Growth models for six Eucalyptus species in Angola

Abstract

This study developed growth models for Eucalyptus saligna Sm., E. camaldulensis Dehnh., E. macarthurii H.Deane & Maiden, E. resinifera Sm., E. siderophloia Benth. and E. grandis Hill ex. Maiden, for the central highlands of Angola, and used these models to simulate the development of stand characteristics. The obtained model set included dominant height, diameter increment, tree height and self-thinning models. The study was based on 10 499 radial increment observations measured on cores taken from about 700 trees growing in 22 plots located in seven sites in the Angolan highlands. The model set makes it possible to simulate stand development on an individual tree basis. Comparison of simulated stand development and measurements indicated good performance of the models. A non-linear fixed-effects diameter increment model performed best for most species, but a non-calibrated linear mixed-effects model used with the Snowdon correction was better for E.  saligna and E. macarthurii. This study showed a similar dominant height  development of young stands as found in most previous studies done for southern Africa. Some differences emerged at older ages.

Keywords: Eucalyptus camaldulensis, Eucalyptus grandis, Eucalyptus macarthurii, Eucalyptus resinifera, Eucalyptus saligna, Eucalyptus siderophloia, growth and  yield, mixed model, non-linear model, simulation