Breeding objectives for three silvicultural regimes of radiata pine

A generic vertically integrated firm, comprising a production forest, a saw mill, and a pulp mill was modelled under three silvicultural regimes: direc t to pulp, intermediate (includes production thinning), and intensive (incl udes production thinnings and pruning). The harvest age traits included in the breeding objective were total volume (m(3)/ha) and average wood density (kg/m(3)). Economic values for each trait were calculated as the differenc e in discounted profit for a unit marginal increase of volume or density, a nd expressed as relative weights to facilitate comparisons between the obje ctives. The methodology was applied to a Chilean case study using represent ative economic and production circumstances. The breeding objectives so der ived were 1vol + 2.4den for pulp, 1vol + 1.1den for intermediate, and 1vol + 1.2den for the intensive regime, where vol and den are the breeding value s for volume and density, respectively. The firm was profitable under all r egimes. Genetic correlations between the objectives for each regime were hi gher than 0.9, indicating that a single breeding strategy with objective 1v ol + 1.5den could be adopted, with almost no loss of genetic gain relative to selecting for a particular silvicultural regime.