Radiata : an economic breeding objective : the definition of an economic breeding objective for plantation radiata pine grown to produce timber flitch and newsprint and an investigation of some aspects related to short-rotation breeding in general using plantation eucalypts as an example

An economic breeding objective was defined for unpruned radiata pine grown to produce structural grade timber flitch and high brightness newsprint from thermomechanical pulp (TMP) in Australia. A production enterprise model was developed including all sources of income (sale of flitch and newsprint) and costs (including growing, harvesting, transporting and mill processing components). The enterprise, as modelled, was shown to be profitable (Profitability Index 19.9%, assuming a discount rate of 5%). The majority of wood volume was assumed to be utilised to produce high brightness newsprint (77% by volume), with only 23% used to produce rough green flitch. The effect of future changes in growth, bark volume, stem sweep, stem taper, branch quality, timber strength, basic density, tracheid length, tracheid coarseness and wood brightness (breeding objective traits) on the profitability of this production enterprise was modelled by defining profit functions relating each of these traits to the economics of each stage of production. Sensitivity analysis was employed throughout this process to examine which assumptions were driving profitability, and identify any that may need verification. For each trait an economic weight was estimated as the incremental Profitability Index associated with a unit increa, se in each trait. Basic density, mean tracheid length and wood brightness were demonstrated as having a major effect on the production of high brightness newsprint from TMP. Growth, as expected, had a large impact on the cost of growing a plantation, however was predicted to be only of moderate to low importance in increasing enterprise profitbability overall. Branch index was shown to have a major impact on the profitability of the flitch production line of the enterprise. Bark volume, stem sweep, stem taper and tracheid coarseness appeared to have a very low impact on production system profitability. However, the importance of stem sweep and stem taper as well as branch index and timber strength are likely to become more important if the enterprise increases its production ratio of flitch to newsprint. An investigation into multi-trait selection strategies clearly demonstrated the dominance of basic density as a selection trait on enterprise profitability. The assessment of wood and tracheid properties is much more costly than assessment of growth and form traits. However it was demonstrated that the gains predicted from individual-tree selections compared with selection based on family-means for basic density and tracheid length are significant and well worth the additional associated cost

Genetic parameters for growth, wood density and pulp yield in Eucalyptus globulus

Genetic variation and co-variation among the key pulpwood selection traits for Eucalyptus globulus were estimated for a range of sites in Portugal, with the aim of improving genetic parameters used to predict breeding values and correlated response to selection. The trials comprised clonally replicated full-sib families (eight trials) and unrelated clones (17 trials), and exhibited varying levels of pedigree connectivity. The traits studied were stem diameter at breast height, Pilodyn penetration (an indirect measure of wood basic density) and near infrared reflectance predicted pulp yield. Univariate and multivariate linear mixed models were fitted within and across sites, and estimates of additive genetic, total genetic, environmental and phenotypic variances and covariances were obtained. All traits studied exhibited significant levels of additive genetic variation. The average estimated within-site narrowsense heritability was 0.19±0.03 for diameter and 0.29± 0.03 for Pilodyn penetration, and the pooled estimate for predicted pulp yield was 0.42±0.14. When they could be tested, dominance and epistatic effects were generally not statistically significant, although broad-sense heritability estimates were slightly higher than narrow-sense heritability estimates. Averaged across trials, positive additive (0.64±0.08), total genetic (0.58±0.04), environmental (0.38±0.03) and phenotypic (0.43±0.02) correlation estimates were consistently obtained between diameter and Pilodyn penetration. This data argues for at least some form of pleiotropic relationship between these two traits and that selection for fast growth will adversely affect wood density in this population. Estimates of the across-site genetic correlations for diameter and Pilodyn penetration were high, indicating that the genotype by environment interaction is low across the range of sites tested. This result supports the use of single aggregated selection criteria for growth and wood density across planting environments in Portugal, as opposed to having to select for performance in different environment

Radiata : an economic breeding objective : the definition of an economic breeding objective for plantation radiata pine grown to produce timber flitch and newsprint and an investigation of some aspects related to short-rotation breeding in general using plantation eucalypts as an example

An economic breeding objective was defined for unpruned radiata pine grown to produce structural grade timber flitch and high brightness newsprint from thermomechanical pulp (TMP) in Australia. A production enterprise model was developed including all sources of income (sale of flitch and newsprint) and costs (including growing, harvesting, transporting and mill processing components). The enterprise, as modelled, was shown to be profitable (Profitability Index 19.9%, assuming a discount rate of 5%). The majority of wood volume was assumed to be utilised to produce high brightness newsprint (77% by volume), with only 23% used to produce rough green flitch. The effect of future changes in growth, bark volume, stem sweep, stem taper, branch quality, timber strength, basic density, tracheid length, tracheid coarseness and wood brightness (breeding objective traits) on the profitability of this production enterprise was modelled by defining profit functions relating each of these traits to the economics of each stage of production. Sensitivity analysis was employed throughout this process to examine which assumptions were driving profitability, and identify any that may need verification. For each trait an economic weight was estimated as the incremental Profitability Index associated with a unit increa, se in each trait. Basic density, mean tracheid length and wood brightness were demonstrated as having a major effect on the production of high brightness newsprint from TMP. Growth, as expected, had a large impact on the cost of growing a plantation, however was predicted to be only of moderate to low importance in increasing enterprise profitbability overall. Branch index was shown to have a major impact on the profitability of the flitch production line of the enterprise. Bark volume, stem sweep, stem taper and tracheid coarseness appeared to have a very low impact on production system profitability. However, the importance of stem sweep and stem taper as well as branch index and timber strength are likely to become more important if the enterprise increases its production ratio of flitch to newsprint. An investigation into multi-trait selection strategies clearly demonstrated the dominance of basic density as a selection trait on enterprise profitability. The assessment of wood and tracheid properties is much more costly than assessment of growth and form traits. However it was demonstrated that the gains predicted from individual-tree selections compared with selection based on family-means for basic density and tracheid length are significant and well worth the additional associated cost

Radiata: An Economic Breeding Objective

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Radiata : an economic breeding objective : the definition of an economic breeding objective for plantation radiata pine grown to produce timber flitch and newsprint and an investigation of some aspects related to short-rotation breeding in general using plantation eucalypts as an example

An economic breeding objective was defined for unpruned radiata pine grown to produce structural grade timber flitch and high brightness newsprint from thermomechanical pulp (TMP) in Australia. A production enterprise model was developed including all sources of income (sale of flitch and newsprint) and costs (including growing, harvesting, transporting and mill processing components). The enterprise, as modelled, was shown to be profitable (Profitability Index 19.9%, assuming a discount rate of 5%). The majority of wood volume was assumed to be utilised to produce high brightness newsprint (77% by volume), with only 23% used to produce rough green flitch. The effect of future changes in growth, bark volume, stem sweep, stem taper, branch quality, timber strength, basic density, tracheid length, tracheid coarseness and wood brightness (breeding objective traits) on the profitability of this production enterprise was modelled by defining profit functions relating each of these traits to the economics of each stage of production. Sensitivity analysis was employed throughout this process to examine which assumptions were driving profitability, and identify any that may need verification. For each trait an economic weight was estimated as the incremental Profitability Index associated with a unit increa, se in each trait. Basic density, mean tracheid length and wood brightness were demonstrated as having a major effect on the production of high brightness newsprint from TMP. Growth, as expected, had a large impact on the cost of growing a plantation, however was predicted to be only of moderate to low importance in increasing enterprise profitbability overall. Branch index was shown to have a major impact on the profitability of the flitch production line of the enterprise. Bark volume, stem sweep, stem taper and tracheid coarseness appeared to have a very low impact on production system profitability. However, the importance of stem sweep and stem taper as well as branch index and timber strength are likely to become more important if the enterprise increases its production ratio of flitch to newsprint. An investigation into multi-trait selection strategies clearly demonstrated the dominance of basic density as a selection trait on enterprise profitability. The assessment of wood and tracheid properties is much more costly than assessment of growth and form traits. However it was demonstrated that the gains predicted from individual-tree selections compared with selection based on family-means for basic density and tracheid length are significant and well worth the additional associated cost