| The economic potential of three pine hybrids and their parent species was examined for South Africa. The studied taxa were the P. patula x P. tecunumanii, P. greggii x P. tecunumanii , and P. taeda x P. tecunumanii hybrids, as well as their parent species. A model was developed for use in determining the profitability of a tree-breeding program with pine hybrids in commercial plantations. Pine hybrids and the parent species were characterized for growth as well as their wood and pulp properties. The influence of volume yield and wood properties of pine hybrids and parent species on the financial performance of a modeled South African pulp mill was assessed. An optimization model to estimate the trade-off between profits and species diversity in a vertically integrated forestry company was developed.;Growth measurement data and wood samples were collected in four twelve-year-old genetic trials in Mondi South Africa and Sappi Forests. Growth models developed for P. patula in South Africa were used to infer models for P. greggii and P. tecunumanii. These models, together with South African P. taeda models, were used to calculate the optimal financial rotation age at discount rates of 6%, 8%, and 12%. Financial data were collected from different sources in South Africa. The model output shows the net present value (NPV), the internal rate of return (IRR), and the minimum area that a tree grower has to plant every year in order to justify the investment in a tree-breeding program. A stochastic approach with Montecarlo Simulation showed that the sensitivity of NPV to uncertainty in the wood price and currency exchange rate was greater than that for the planting, harvesting, and hauling costs.;The characterization results indicated that the hybrid growth may be either superior to that of the best of the parent species, equal to the best parent species, or intermediate between the parent species. Wood chemistry, wood density, pulp yield, bleaching, fiber, and hand-sheet properties were also measured for all the taxa following well-recognized lab standards. The most frequent position of hybrid traits with respect to parental traits is the intermediate; in a few cases, the position was above or below the parental species. For the three hybrids, the value of the hybrid trait was closer to that of the female parent in 70% or more of the cases.;The pulp mill and the forestry models used to calculate the impact of growth, wood density, lignin content, and pulp yield on financial performance showed great differences in NPV among taxa. Two scenarios with manufacturing bottlenecks limiting pulp production were used in the pulp mill model, one in the recovery boiler and one in the pulp dryer. Results under the two scenarios showed differences over ;A linear programming model was developed to optimize profits and species diversity of an integrated company owning a kraft pulp mill and commercial plantations. Wood density, pulp yield, volume yield, wood lignin content, and total pulping costs were included as parameters. Constraints on pulp production, solubilized lignin, and annual planting area by species were applied. Six different analyzed cases illustrate the trade-offs between annual profits and species diversity. |
