Assessing the economic impact of an emissions trading scheme on agroforestry in Australia’s northern grazing systems

Although agriculture generates a significant portion of Australia’s greenhouse gas emissions, it also has the potential to sequester large quantities of emissions through changed land use management such as agroforestry. Whilst there is an extensive amount of agroforestry literature, little has been written on the economic consequences of adopting silvopastoral systems in northern Australia. This paper reports the economic feasibility of adopting complimentary agroforestry systems in the low rainfall region of northern Australia. The analysis incorporates the dynamic tradeoffs between tree and pasture growth, carbon sequestration, cleared regrowth decomposition rates and livestock methane emissions in a bioeconomic model. The results suggest there are financial benefits for landholders who integrate complimentary agroforestry activities into existing grazing operations depending on the rules of the carbon accounting framework used.carbon sequestration, financial analysis, carbon accounting framework, Agroforestry, Resource /Energy Economics and Policy,

Reconciling conflicting evidence for the cause of the observed early 21st century Eurasian cooling

It is now well established that the Arctic is warming at a faster rate than the global average. This warming, which has been accompanied by a dramatic decline in sea ice, has been linked to cooling over the Eurasian subcontinent over recent decades, most dramatically during the period 1998–2012. This is a counter-intuitive impact under global warming given that land regions should warm more than ocean (and the global average). Some studies have proposed a causal teleconnection from Arctic sea-ice retreat to Eurasian wintertime cooling; other studies argue that Eurasian cooling is mainly driven by internal variability. Overall, there is an impression of strong disagreement between those holding the “ice-driven” versus “internal variability” viewpoints. Here, we offer an alternative framing showing that the sea ice and internal variability views can be compatible. Key to this is viewing Eurasian cooling through the lens of dynamics (linked primarily to internal variability with some potential contribution from sea ice; cools Eurasia) and thermodynamics (linked to sea-ice retreat; warms Eurasia). This approach, combined with recognition that there is uncertainty in the hypothesized mechanisms themselves, allows both viewpoints (and others) to co-exist and contribute to our understanding of Eurasian cooling. A simple autoregressive model shows that Eurasian cooling of this magnitude is consistent with internal variability, with some periods exhibiting stronger cooling than others, either by chance or by forced changes. Rather than posit a “yes-or-no” causal relationship between sea ice and Eurasian cooling, a more constructive way forward is to consider whether the cooling trend was more likely given the observed sea-ice loss, as well as other sources of low-frequency variability. Taken in this way both sea ice and internal variability are factors that affect the likelihood of strong regional cooling in the presence of ongoing global warming.publishedVersio

Reconciling conflicting evidence for the cause of the observed early 21st century Eurasian cooling

It is now well established that the Arctic is warming at a faster rate than the global average. This warming, which has been accompanied by a dramatic decline in sea ice, has been linked to cooling over the Eurasian subcontinent over recent decades, most dramatically during the period 1998–2012. This is a counter-intuitive impact under global warming given that land regions should warm more than ocean (and the global average). Some studies have proposed a causal teleconnection from Arctic sea-ice retreat to Eurasian wintertime cooling; other studies argue that Eurasian cooling is mainly driven by internal variability. Overall, there is an impression of strong disagreement between those holding the “ice-driven” versus “internal variability” viewpoints. Here, we offer an alternative framing showing that the sea ice and internal variability views can be compatible. Key to this is viewing Eurasian cooling through the lens of dynamics (linked primarily to internal variability with some potential contribution from sea ice; cools Eurasia) and thermodynamics (linked to sea-ice retreat; warms Eurasia). This approach, combined with recognition that there is uncertainty in the hypothesized mechanisms themselves, allows both viewpoints (and others) to co-exist and contribute to our understanding of Eurasian cooling. A simple autoregressive model shows that Eurasian cooling of this magnitude is consistent with internal variability, with some periods exhibiting stronger cooling than others, either by chance or by forced changes. Rather than posit a “yes-or-no” causal relationship between sea ice and Eurasian cooling, a more constructive way forward is to consider whether the cooling trend was more likely given the observed sea-ice loss, as well as other sources of low-frequency variability. Taken in this way both sea ice and internal variability are factors that affect the likelihood of strong regional cooling in the presence of ongoing global warming.</p

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Application of tree and stand allometrics to the determination of biomass and its flux in some north-east Australian woodlands: Tree and stand allometrics

Examines the effects of species, rainfall and soil type on tree biomass regressions, as well as the effects of stand dominance and structure on stand biomass regrassions in north-east Australian woodlands.. "This thesis examines the effects of species, rainfall and soil type on tree biomass regressions, as well as the effects of stand dominance and structure on stand biomass regressions in north-east Australian woodlands. This was achieved by examining tree characteristics and biomass relationships for a series of woodland monitoring sites throughout the study area. This study utilised a modified data set from this permanent monitoring site network to provide structural attributes for trees and communities of varying composition in the grazed woodlands. These data were supplemented with environmental data and tree harvest data sets. Initially, the research reported in this thesis developed allometric and stand biomass regressions for Callitris glaucophylla communities. This research also demonstrated that changes in tree-form were not reflected in changes in the environment, nor did such changes reflect changes in tree biomass regressions for three eucalypt species. As a result, a common regression provides a robust estimate of total aboveground biomass of eucalypt trees in the study area. Thus expensive destructive harvesting can generally be avoided for minor eucalypt species. Finally, this study demonstrated a successful methodology that described the stand structure of all the grazed woodland sites based on tree heights. This methodology was developed to allow the expansion of a single stand regression to estimate stand biomass across the entire north-east Australian woodlands. The findings demonstrated in this study, combined with the long-term data from the permanent monitoring network sites, should enhance the estimation of carbon flux within eucalypt communities of north-east Australias grazed woodlands." -- abstract

Assessing the economic impact of an emissions trading scheme on agroforestry in Australia’s northern grazing systems

Although agriculture generates a significant portion of Australia’s greenhouse gas emissions, it also has the potential to sequester large quantities of emissions through changed land use management such as agroforestry. Whilst there is an extensive amount of agroforestry literature, little has been written on the economic consequences of adopting silvopastoral systems in northern Australia. This paper reports the economic feasibility of adopting complimentary agroforestry systems in the low rainfall region of northern Australia. The analysis incorporates the dynamic tradeoffs between tree and pasture growth, carbon sequestration, cleared regrowth decomposition rates and livestock methane emissions in a bioeconomic model. The results suggest there are financial benefits for landholders who integrate complimentary agroforestry activities into existing grazing operations depending on the rules of the carbon accounting framework used

Patterns of below- to above-ground biomass ratio and root distribution in Eucalyptus populnea woodland communities of northeast Australia along a rainfall gradient

In vegetated terrestrial ecosystems, carbon in below- and aboveground biomass (BGB, AGB) often constitutes a significant component of total-ecosystem carbon stock. Because carbon in the BGB is difficult to measure, it is often estimated using BGB to AGB ratios. However, this ratio can change markedly along resource gradients, such as water availability, which can lead to substantial errors in BGB estimates. In this study, BGB and AGB sampling was carried out in Eucalyptus populnea-dominated woodland communities of northeast Australia to examine patterns of BGB to AGB ratio and vertical root distribution at three sites along a rainfall gradient (367, 602, and 1,101 mm). At each site, a vegetation inventory was undertaken on five transects (100 à 4 m), and trees representing the E. populnea vegetation structure were harvested and excavated to measure aboveground and coarse-root (diameter of at least 15 mm) biomass. Biomass of fine and small roots (diameter less than 15 mm) at each site was estimated from 40 cores sampled to 1 m depth. The BGB to AGB ratio of E. populnea-dominated woodland plant communities declined from 0.58 at the xeric end to 0.36 at the mesic end of the rainfall gradient. This was due to a marked decline in AGB with increased aridity whereas the BGB was relatively stable. The vertical distribution of fine roots in the top 1 m of soil varied along the rainfall gradient. The mesic sites had more fine-root biomass (FRB) in the upper soil profile and less at depth than the xeric site. Accordingly, at the xeric site, a much larger proportion of FRB was found at depth compared to the mesic sites. The vertical distribution patterns of small roots of the E. populnea woodland plant communities were consistently )-shaped, with the highest biomass occurring at 15–30-cm depth. The potential significance of such a rooting pattern for grass–tree and shrub����tree co-existence in these ecosystems is discussed. Overall, our results revealed marked changes in BGB to AGB ratio of E. populnea woodland communities along a rainfall gradient. Because E. populnea woodlands cover a large area (96 M ha), their contribution to continental-scale carbon sequestration and greenhouse gas emission can be substantial. Use of the rainfall-zone-specific ratios found in this study, in lieu of a single generic ratio for the entire region, will significantly improve estimates of BGB carbon stocks in these woodlands. In the absence of more specific data, our results will also be relevant in other regions with similar vegetation and rainfall gradients (that is, arid and semiarid woodland ecosystems)

The bioeconomic potential for agroforestry in northern cattle grazing systems : an evaluation of tree alley scenarios in central Queensland

Extensive land clearing for livestock production and associated land degradation has led to greater interest in the role of trees and revegetation practices such as agroforestry for achieving productivityand environmental outcomes in pastoral landscapes. RIRDC recently funded a national scale analysis (Polglase et al. 2008) of the potential to grow and profitably market wood products. Whilst there is now a growing understanding of the bio-economic interactions driving plantation hardwoods, there is little known about the economic outcomes of establishing complementary agroforestry and silvopastoralism in northern Australia’s lower rainfall zones (600-750 mm annual rainfall) including central Queensland. Silvopastoralism may offer landholders considerable advantages over traditional grazing systems in terms of income diversification, environmental benefits through increased woody vegetation cover andareas of stimulated versus constrained pasture growth. RIRDC commissioned this investigation to better understand whether an agro-forestry production system produces better financial and environmental outcomes than an extensive grazing system