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Churchill, Australia

Hopmans P.,Timberlands Research Pty. Ltd | Elms S.R.,HVP Plantations
Forest Ecology and Management | Year: 2013

A study of responses of radiata pine (Pinus radiata D. Don) to fertilizer applied after thinning and the impact of repeated infestations of the Monterey pine aphid (Essigella californica Essig.) over 12years showed that the defoliation of upper crowns was exacerbated by nutrient deficiencies of P and S. Remedial treatment with NPS fertilizers in 1997 and 2003 improved average retention of foliage especially during the second 6-year period of the study when damage from annual infestations of aphids was relatively consistent. In 2003 treatment with N, NP and NPS raised N and P in foliage to satisfactory levels while the sulfur status of trees ranged from severe deficiency to satisfactory. This increased average foliage retention by 6%, 12% and 20% compared with unfertilized trees. Corresponding volume responses to N, NP and NPS over 6years were estimated at 12, 45, and 88m3ha-1 at Warrenbayne and 19, 31 and 48m3ha-1 at Stanley indicating a significant response to the remedial treatment of sulfur deficiency.There was considerable variation in aphid damage between trees irrespective of fertilizer treatment reflecting strong genetic variation in susceptibility of radiata pine to defoliation by aphids. This had a substantial impact on tree growth showing a three to fourfold difference in basal area increment over 6. years across a wide range of aphid damage classes. The reduction in basal area increment was strongly correlated with average retention of upper crown foliage. Although remedial treatment with NPS increased average foliage retention from 50% to 70% therefore reducing aphid damage by 20%, a significant proportion of trees (around 25%) continued to be severely defoliated by aphids and did not respond to fertilizer. The reduction in basal area growth due to defoliation of trees treated with NPS fertilizer was estimated at approximately 30% over 6. years. Selective removal of susceptible trees at thinning was shown to be a feasible management strategy without any unacceptable changes in stand structure and reduced potential defoliation by aphids by 15%. This together with remedial fertilizer treatment provides a viable option for the management of radiata pine plantations to reduce aphid damage and improve stand productivity. © 2012 Elsevier B.V. Source

Bren L.,University of Melbourne | Elms S.,HVP Plantations | Costenaro J.,University of Melbourne
Australian Forestry | Year: 2011

The concept of 'virtual water' is the amount of water that is embedded in products and used in their production. For commercially-grown wood this is the évapotranspiration per cubic metre or per tonne of product. A Pinus radiata plantation on a paired catchment project ('Croppers Creek') in north-eastern Victoria, Australia, was destroyed in a major wildfire. Salvagelogging of the area provided an excellent opportunity to compute this parameter. If data from the entire research catchment was included, the result was a virtual water volume value of 796 m 3 of water per cubic metre of radiata pine log product. If pre-treatment data were used to correct for the presence of a retained riparian strip of native eucalypt forest the result obtained was a virtual water volume value of 771 m 3 of water per cubic metre of product. If the results are converted to dry weight then the values become 1768 and 1713m 3 of water per tonne of product. These results are similar to those of products such as rice or wheat. We cannot find comparable values for other wood products. Although the concept of virtual water is attractive, the utility of the value obtained is arguable. The scientific alternative of water-use efficiency is more credible but the information available on this tends to be for individual plants over short periods of time. Source

Ivkovic M.,CSIRO | Baltunis B.,CSIRO | Gapare W.,CSIRO | Sasse J.,Sassafras Group | And 3 more authors.
Canadian Journal of Forest Research | Year: 2010

Pine needle blight, caused by Dothistroma septosporum (Dorog.) M. Morelet, is one of the most serious foliar diseases of Pinus spp. in Australia and New Zealand. In 16 Pinus radiata (D.Don.) progeny trials in northeastern Victoria, Australia, Dothistroma-caused defoliation varied widely among trials and assessment years, ranging from 5% to 65%. The estimated narrow sense heritability ranged from nonsignificant to as high as 0.69 with a median of 0.36. Spatial autocorrelation of residuals accounted for a significant proportion of residual variance, and that increased heritability estimates. Genetic correlation between defoliation scores at an early age and growth at a later age was negative with a median value of -0.39. Phenotypic correlation between defoliation and survival was low and negative with a median value of -0.11. Economic analyses indicated that at sites with a high risk of infection, the effect of reducing defoliation on profitability was comparable with that of increasing growth at sites free from infection. The genetic parameters and economic impacts of Dothistroma were used to derive selection indices and include resistance to defoliation into the current breeding objective for radiata pine. Source

Ivkovic M.,CSIRO | Gapare W.J.,CSIRO | Wharton T.,CSIRO | Jovanovic T.,CSIRO | And 3 more authors.
Australian Forestry | Year: 2010

This paper examines the effects of climatic and biotic risks -drought, Essigella aphid, Dothistroma needle blight and Fusarium pitch canker-on the Pinus radiata production system in Australia. These risks were examined in relation to climatic variables in order to develop 'hazard ratings' for planting sites. Bio-economic models were developed to link the risks with the established breeding objective for solid wood production. Economic weights were derived for resistance traits that can be used in index selection for breeding and deployment. Under one scenario, drought-affected sites can achieve an internal rate of return of > 7.0% only if the land rental is sufficiently low, that is <$25 ha-1 y-1, but replanting costs and volume losses due to mortality can be significant. An average of 13.5% defoliation caused by Essigella aphid would reduce volume growth over a rotation period by about 10%. A modest increase in profitability can be achieved through deployment of Essiggella-resistant genotypes. Reduction of volume growth by Dothistroma defoliation at an early age (4-10 y) had a relatively small effect on subsequent yield reduction. At a site with a high level of infection, however, the profitability of improving Dothistroma resistance was similar to that for improving growth on uninfected sites. The economic importance of risk traits relative to MAI over the entire radiata pine plantation estate was generally low: 4% for pine aphid, 0.6% for needle blight and 1.3% for pitch canker resistance. Essigella pine aphid is the most important pest currently affecting the productivity of radiata pine plantations in Australia. Source

Eyles A.,Cooperative Research Center for Greenhouse Gas Technologies | Eyles A.,University of Melbourne | Eyles A.,University of Tasmania | Smith D.,University of Melbourne | And 9 more authors.
Tree Physiology | Year: 2011

The phloem-feeding aphid Essigella californica represents a potential threat to the productivity of Pinus radiata plantations in south-eastern Australia. Five- and nine-year-old field trials were used to characterize the effects of artificial and natural aphid-induced (E. californica) defoliation, respectively, on shoot photosynthesis and growth. Photosynthetic capacity (A max) was significantly greater following a 25% (D25) (13.8 μmol m -2 s -1) and a 50% (D50) (15.9 μmol m -2 s -1) single-event upper-crown artificial defoliation, 3 weeks after defoliation than in undefoliated control trees (12.9 μmol m -2 s -1). This response was consistently observed for up to 11 weeks after the defoliation event; by Week 16, there was no difference in A max between control and defoliated trees. In the D50 treatment, this increased A max was not sufficient to fully compensate for the foliage loss as evidenced by the reduced diameter increment (by 15%) in defoliated trees 36 weeks after defoliation. In contrast, diameter increment of trees in the D25 treatment was unaffected by defoliation. The A max of trees experiencing upper-crown defoliation by natural and repeated E. californica infestations varied, depending on host genotype. Despite clear differences in defoliation levels between resistant and susceptible genotypes (17 vs. 35% of tree crown defoliated, respectively), growth of susceptible genotypes was not significantly different from that of resistant genotypes. The observed increases in A max in the lower crown of the canopy following attack suggested that susceptible genotypes were able to partly compensate for the loss of foliage by compensatory photosynthesis. The capacity of P. radiata to regulate photosynthesis in response to natural aphid-induced defoliation provides evidence that the impact of E. californica attack on stem growth will be less than expected, at least for up to 35% defoliation. © The Author 2011. Source

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