Allometric relationships and community biomass estimates for some dominant eucalypts in Central Queensland woodlands

Allometric equations are presented relating stem circumference to branch, leaf, trunk, bark, total above-ground and lignotuber biomass for Eucalyptus crebra F.Muell. (woodland trees), E. melanophloia Sol. Ex Gaerth. (both woodland and regrowth community trees) and E. populnea F.Muell. (woodland trees). There were no significant differences (P > 0.05) between the slopes of individual lognormal regression lines plotting stem circumference against total above-ground biomass for E. crebra, E. melanophloia and E. populnea. Root-to-shoot ratios and leaf area indices were also determined for the stands contributing to each regression. The regressions were then applied to measured eucalypt stems in the associated plant community to give estimates of each stand’s component (eucalypt tree fraction only) biomass per hectare. These eucalypt regressions were next applied to measured stems of each species on a total of 33 woodland sites in which these eucalypts individually contributed > 75% of total site basal area. Above-ground biomass/basal area relationships averaged 6.74 0.29 t m–2 basal area for 11 E. crebra sites, 5.11 0.28 t m–2 for 12 E. melanophloia sites and 5.81 0.11 t m–2 for 10 E. populnea sites. The mean relationship for all sites was 5.86 0.18 t m–2 basal area. The allometric relationships presented at both individual tree and stand levels, along with calculated biomass : basal area relationships, enable ready estimates to be made of above-ground biomass (carbon stocks) in woodlands dominated by these eucalypts in Queensland, assuming individual stem circumferences or community basal areas are known. However, to document changes in carbon stocks (e.g. for Greenhouse Gas Inventory or Carbon Offset trading purposes), more attention needs to be placed on monitoring fluxes in the independent variables (predictors) of these allometric equations

Dependence of hadron spectra on decoupling temperature and resonance contributions

Using equilibrium hydrodynamics with initial conditions for the energy and net baryon number densities from the perturbative QCD + saturation model, a good simultaneous description of the measured pion, kaon and (anti)proton spectra in central Au+Au collisions at $\sqrt s=130 A$GeV is found with a single decoupling temperature \Tdec=150...160 MeV. The interplay between the resonance content of the EoS and the development of the transverse flow leads to inverse slopes and $$ of hadrons which increase with decreasing \Tdec. The origin of this result is discussed.Comment: 4 pages, 2 eps-figures. Section 3 rewritten, table 1 and figure 1 redrawn, 2 references adde

Multiplicities and Transverse Energies in Central AA Collisions at RHIC and LHC from pQCD, Saturation and Hydrodynamics

We compute the particle multiplicities and transverse energies at central and nearly central AA collisions at RHIC and LHC. The initial state is computed from perturbative QCD supplemented by the conjecture of saturation of produced partons. The expansion stage is described in terms of hydrodynamics assuming longitudinal boost invariance and azimuthal symmetry. Transverse flow effects, a realistic list of hadrons and resonance decays are included. Comparison with the data of the multiplicities at $\sqrt s=56$ AGeV and 130 AGeV from RHIC is done and predictions for the full RHIC energy and LHC energy are made for the multiplicities and transverse energies. The reduction from the initially released minijet transverse energy to the $E_T$ in the final state is less than in the one-dimensional case but still dramatic: a factor of 2.7 at RHIC, and 3.6 at the LHC.Comment: The results for LHC have been correcte

Hydrodynamics and Flow

In this lecture note, we present several topics on relativistic hydrodynamics and its application to relativistic heavy ion collisions. In the first part we give a brief introduction to relativistic hydrodynamics in the context of heavy ion collisions. In the second part we present the formalism and some fundamental aspects of relativistic ideal and viscous hydrodynamics. In the third part, we start with some basic checks of the fundamental observables followed by discussion of collective flow, in particular elliptic flow, which is one of the most exciting phenomenon in heavy ion collisions at relativistic energies. Next we discuss how to formulate the hydrodynamic model to describe dynamics of heavy ion collisions. Finally, we conclude the third part of the lecture note by showing some results from ideal hydrodynamic calculations and by comparing them with the experimental data.Comment: 40 pages, 35 figures; lecture given at the QGP Winter School, Jaipur, India, Feb.1-3, 2008; to appear in Springer Lecture Notes in Physic

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Control of currant bush (Carissa ovata) in developed brigalow (Acacia harpophylla) country

Currant bush (Carissa ovata) is the major native woody weed invading sown buffel grass pastures in cleared brigalow (Acacia harpophylla) forests in Queensland. Stickraking followed by chisel ploughing is a viable alternative to and is more economical than herbicide treatment and blade ploughing for controlling currant bush. Chisel ploughing following stickraking gives good control of currant bush with no detrimental effect on existing buffel grass pasture. Stickraking alone is not sufficient to control currant bush

Control of brigalow (Acacia harpophylla) regrowth by single and double ploughings

Single and double ploughings approximately 10 cm deep in the spring to early autumn period were used in an attempt to control 4-year-old brigalow suckers. Most effective control following a single ploughing was obtained in March

Relationship between burning and spraying in the control of brigalow (Acacia harpophylla) regrowth. 1. Burning as a pre-spraying treatment

Spraying brigalow regrowth following a pasture burn resulted in significantly better control than spraying the unburnt suckers

Some studies on the chemical control of Dawson gum or blackbutt (Eucalyptus cambageana). Part III. Basal bark and cut stump treatment of multi-stemmed regrowth

This paper is the third in a series on the chemical control of Dawson gum (Eucalyptus cambageana Maiden). Results of experimental work into the control of multi-stemmed regrowth, 4 to 6 m high, by basal bark and cut stump treatments are discussed

Control of brigalow (Acacia harpophylla) in cattle country by two aerial spraying applications 10 months apart

Two sprayings 10 months apart with 1·12 kg acid equivalent (a.e.) 2,4,5-T ester ha-1 reduced the brigalow density of 3 1/2-year-old suckers by 72%. Results with two applications of 0·56 kg a.e. 2,4,5-T ester ha-1 were greatly inferior