A decadal multi-site study of the effects of frequency and season of harvest on biomass production from mallee eucalypts

Mazanec²,

et al. 2020

Sci Rep

Self Cite

Reproductive synchronicity within a seed orchard facilitates gene exchange and reduces self-fertilisation. Here we assessed key flowering traits, biomass and foliar 1,8-cineole concentrations of Eucalyptus loxophleba (subsp. lissophloia and gratiae) in an open-pollinated seed orchard. Monthly flowering observations were made on 1142 trees from 60 families and nine provenances across 2 years. The percentage of trees flowering in both years was similar at 87%. There were differences between provenances and families within provenances for flowering traits, biomass and 1,8-cineole and interactions between provenances and year for flowering traits. Heritability of start and end flowering, and 1,8-cineole were high to moderate ($$\hat{h}^{2}$$ h ^ 2 = 0.75–0.45) and duration of flowering, propensity to flower and biomass estimates were moderate to low ($$\hat{h}^{2}$$ h ^ 2 = 0.31–0.10). Genetic and phenotypic correlations between flowering traits were high (rg = 0.96–0.63 and rp = 0.93–0.34) except between duration and end of flowering. The correlations were weaker between flowering traits and biomass or 1,8-cineole. ‘Dual flowering’, when trees underwent two reproductive cycles in a year, was responsible for out-of-phase flowering and those with low biomass and 1,8-cineole concentration should be removed from the breeding programme to hasten selection for desirable traits.

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Flowering phenology in a Eucalyptus loxophleba seed orchard, heritability and genetic correlation with biomass production and cineole: breeding strategy implications

Mazanec²,

et al. 2020

Sci Rep

Self Cite

“…Subsequently, Abadi et al (2012) modelled the economics of a mallee biomass production system and suggested that the cost of production was in the range of AUD53-AUD70 per Mg of fresh biomass with co-benefits valued at between AUD2 and AUD15 Mg −1 . This paper considers the economic viability of mallee in an agroforestry system using a decadal experiment providing yield data from mallee belts with six harvesting treatments across 19 sites (Spencer et al, 2019) and crop and pasture yields measured adjacent to the belts over 6 years (Sudmeyer et al, 2012). These data sets provide a unique opportunity to assess the economic viability of mallee using experimental data obtained from operational short rotation coppice systems with real-world management by farmers (Hauk et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

“…alley farming systems (Spencer et al, 2019;Sudmeyer et al, 2012). Sites were established in 2006 with 5-to 12-year-old mallee belts on privately owned farms in the wheatbelt of WA ( Figure 1; Table 1).…”

Section: Introductionmentioning

confidence: 99%

Determinants of the economic viability of mallee eucalypts as a short rotation coppice crop integrated into farming systems of Western Australia

Bartle³

et al. 2020

GCB Bioenergy

Self Cite

Planting configuration affects productivity, tree form and survival of mallee eucalypt in farm forestry plantings

Bartle²,

et al. 2020

Agroforest Syst

Self Cite

Mallee eucalypts have been extensively planted in the Western Australia wheatbelt for salinity mitigation and as a short-rotation coppice crop for the production of cineole and bioenergy feedstocks. Mallee has been planted in wide-spaced narrow belts (2-6 rows) within annual crops and pasture, but optimal planting configurations have not been determined. Here, we assess the biomass yield responses of Eucalyptus loxophleba ssp. lissophloia and E. polybractea to; four row treatments (1, 2, 4 and 6 row belts) and five within-row spacing treatments (1, 1.5, 2, 3 and 4 m). Thirteen years after planting, the row effects on plot-level biomass productivity of E. loxophleba ranged from 4.3 to 21.2 Mg ha -1 year -1 . For E. polybractea, both row number and within-row spacing affected yield, which ranged from 2.7 to 18.8 Mg ha -1 year -1 . For both species, the highest growth rates were observed in the one-row belts with shorter (<3 m) within-row spacing. Within the belts, reductions of growth rate were observed with additional rows, due to increased competition and significant suppression of internal rows; and with wider within-row spacing, due to lower initial planting density. However, when including the area between belts, wider belts generated more biomass. For both species, average tree size decreased with additional rows and shorter within-row spacing.For both species, the number of stems per tree increased with wider within-row spacing, and also for E. polybractea, with fewer rows. The substantial variation in productivity, tree size and form found in these results will affect harvestability and ultimately the economic viability of future mallee plantings.