Productivity of Pinus elliottii, P. caribaea and their F1 and F2 hybrids to 15 years in Queensland, Australia

Growth data are presented to 15 years of age from a genetic study involving factorial matings within and between P. elliottii var. elliottii and P. caribaea var. hondurensis, planted across three sites in southeast Queensland. Specific volume equations developed using the centroid method for each taxon/site combination as well as a generic (i.e. conical) volume equation, were used to estimate the mean annual increment (MAI) at 10 and 15 years of age. MAI estimated using the conical volume equation were downwardly biased by 18% in P. elliottii but the bias was less than 2% in P. caribaea var. hondurensis, and yielded different rankings of taxa at each site compared to the taxon/site specific volume equations. At all three sites, P. caribaea var. hondurensis and the F₁ and F₂ hybrids significantly exceeded the productivity of P. elliottii; however, differences between P. caribaea var. hondurensis and hybrid pine were generally small. Assuming a realistic contribution of the three site-types to the population of deployment environments, average MAIs for southeast Queensland were estimated as: 17.6, 23.0, 23.7 and 23.5 m³ ha^?1 y^?1 for Pee, Pch, F₁ and F₂ respectively.