Professor Derek Eamus

Eamus, D., Hatton, T., Cook, P. & Colvin, C. 2006, Ecohydrology: Vegetation Function, Water and Resource Management, 1, CSIRO Publishing, Collingwood, VIC Australia.
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This book is not a textbook on Australian ecology. The purpose of this text is to reveal and discuss the links between vegetation function and water in landscapes - that is, to discuss ecohydrology.We focus primarily (but not exclusively) on the interactions among the woody components of vegetation, rainfall and changes in groundwater availability.Woody vegetation is the focus because of the centrality of changes in woody vegetation cover to the ecohydrology of Australia over the past 100 to 200 years. Furthermore we focus on vegetation function (ecophysiology) rather than structure, because it is the functioning of vegetation that influences hydrology inthe first instance. Although this book uses Australian examples,the principles, philosophy and methodological approach are applicable worldwide.

Eamus, D. & Ceulemans, R. 2001, 'Effects of Greenhouse Gasses on the Gas Exchange of Forest Trees' in Karnosky DF; Ceulemans R (eds), The Impact of Carbon Dioxide and Other Greenhouse Gasses on Forest Ecosystem, CABI International, Wallingford, UK, pp. 17-56.

Eamus, D. 2000, 'Some Tree Responses to CO2 Enrichment' in Singh SN (ed), Trace Gas Emissions and Plants, Kluwer Academic Publishers, Netherlands, pp. 75-95.

Lv, J., Wang, X., Zhou, Y., Qian, K., Wan, L., Eamus, D. & Tao, Z. 2013, 'Groundwater-dependent distribution of vegetation in Hailiutu River catchment, a semi-arid region in China', Ecohydrology, vol. 6, no. 1, pp. 142-149.
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In arid and semi-arid regions, groundwater availability is one of the controls on vegetation distribution. This groundwater-dependent distribution of vegetation has been particularly observed in the Hailiutu River catchment, a semi-arid region in North China. We used remote sensing images of vegetation index (normalized difference vegetation index, NDVI) and field data of depth to water table (DWT) to assess the response of vegetation distribution on increase of DWT at the regional scale. The frequency distribution curves of NDVI with respect to different DWT were obtained. The statistical distributions of NDVI values at different DWT intervals indicate that higher vegetation coverage and more plant diversity exist at places of shallow groundwater. Both the mean and the standard deviation of NDVI values decrease with the increase of groundwater depth when DWT is less than 10?m. Beyond that depth, a low level of vegetation coverage and diversity is maintained. Comparisons of different sub-areas within the region with different dominant species showed that the NDVI of shrubs is sensitive to DWT. In contrast, NDVI of herbs is not significantly influenced by DWT. The relationship between NDVI and groundwater depth in farmlands could not be reliably determined because of disturbance by human activities. We conclude that application of this methodology may significantly improve our ability on sustainable management of land and groundwater resources.

Ponce Campos, G.E., Moran, M.S., Huete, A., Zhang, Y., Bresloff, C., Huxman, T.E., Eamus, D., Bosch, D.D., Buda, A.R., Gunter, S.A., Heartsill Scalley, T., Kitchen, S.G., McClaran, M.P., McNab, W.H., Montoya, D.S., Morgan, J.A., Peters, D.P., Sadler, E.J., Seyfried, S. & Starks, P.J. 2013, 'Ecosystem resilience despite large-scale altered hydroclimatic conditions', Nature, vol. 494, pp. 349-353.
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Climate change is predicted to increase both drought frequency and duration, and when coupled with substantial warming, will establish a new hydroclimatological model for many regions1. Largescale, warm droughts have recently occurred in North America, Africa, Europe, Amazonia and Australia, resulting in major effects on terrestrial ecosystems, carbon balance and food security2,3. Here we compare the functional response of above-ground net primary production to contrasting hydroclimatic periods in the late twentieth century (1975Ô++1998), and drier, warmer conditions in the early twenty-first century (2000Ô++2009) in the Northern and Southern Hemispheres. We find a common ecosystem water-use efficiency (WUEe: above-ground net primary production/evapotranspiration) across biomes ranging from grassland to forest that indicates an intrinsic system sensitivity to water availability across rainfall regimes, regardless of hydroclimatic conditions. We found higher WUEe in drier years that increased significantly with drought to a maximum WUEe across all biomes; and a minimum native state in wetter years that was common across hydroclimatic periods. This indicates biome-scale resilience to the interannual variability associated with the early twenty-first century droughtÔ++that is, the capacity to tolerate low, annual precipitation and to respond to subsequent periods of favourable water balance. These findings provide a conceptual model of ecosystem properties at the decadal scale applicable to the widespread altered hydroclimatic conditions that are predicted for later this century. Understanding the hydroclimatic threshold that will break down ecosystem resilience and alter maximum WUEe may allow us to predict land-surface consequences as large regions become more arid, starting with waterlimited, low-productivity grasslands.

Whitley, R.J., Taylor, D.T., Macinnis-Ng, C., Zeppel, M., Yunusa, I., O'Grady, A., Froend, R., Medlyn, B. & Eamus, D. 2013, 'Developing an empirical model of canopy water flux describing the common response of transpiration to solar radiation and VPD across five contrasting woodlands and forests', Hydrological Processes, vol. 27, pp. 1133-1146.
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A modified Jarvis´+¢Stewart model of canopy transpiration (Ec) was tested over five ecosystems differing in climate, soil type and species composition. The aims of this study were to investigate the model's applicability over multiple ecosystems; to determine whether the number of model parameters could be reduced by assuming that site-specific responses of Ec to solar radiation, vapour pressure deficit and soil moisture content vary little between sites; and to examine convergence of behaviour of canopy water-use across multiple sites. This was accomplished by the following: (i) calibrating the model for each site to determine a set of site-specific (SS) parameters, and (ii) calibrating the model for all sites simultaneously to determine a set of combined sites (CS) parameters. The performance of both models was compared with measured Ec data and a statistical benchmark using an artificial neural network (ANN). Both the CS and SS models performed well, explaining hourly and daily variation in Ec. The SS model produced slightly better model statistics [R2?=?0.75´+¢0.91; model efficiency (ME)?=?0.53´+¢0.81; root mean square error (RMSE)?=?0.0015´+¢0.0280?mm h-1] than the CS model (R2?=?0.68´+¢0.87; ME?=?0.45´+¢0.72; RMSE?=?0.0023´+¢0.0164?mm h-1). Both were highly comparable with the ANN (R2?=?0.77´+¢0.90; ME?=?0.58´+¢0.80; RMSE?=?0.0007´+¢0.0122?mm h-1). These results indicate that the response of canopy water-use to abiotic drivers displayed significant convergence across sites, but the absolute magnitude of Ec was site specific.

Yunusa, I.A., Veeragathipillai, M., Harris, R., Lawrie, R., Pal, Y., Quiton, J.T., Bell, R. & Eamus, D. 2013, 'Differential growth and yield by canola (Brassica napus L.) and wheat (Triticum aestivum L.) arising from alterations in chemical properties of sandy soils due to additions of fly ash', Journal of the Science of Food and Agriculture, vol. 93, pp. 995-1002.
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Zhu, J., Yu, J., Wang, P., Yu, Q. & Eamus, D. 2013, 'Distribution patterns of groundwater-dependent vegetation species diversity and their relationship to groundwater attributes in northwestern China', Ecohydrology, vol. 6, pp. 191-200.
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Ali, M.M., Al-Ani, A., Eamus, D. & Tan, D.K. 2012, 'A New Image Processing Based Technique to Determine Chlorophyll in Plants', American-Eurasian J. Agric. & Environ. Sci., vol. 12, no. 10, pp. 1323-1328.
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Leaf colour is usually used as a guide for assessments of nutrient status and plant health. We propose a new inexpensive, hand-held and easy-to-use technique for the detection of chlorophyll content and foliar nitrogen content in plants based on leaf colour. This method provides a rapid analysis and data storage at minimal cost and does not require any technical or laboratory skills. Most of the existing methods that examined relationships between chlorophyll status and leaf colour were developed for particular species. These methods acquire leaf images using digital cameras, which can be sensitive to lighting conditions (colour, angle, flux density) and hence, require proper calibration. Our method analyses leaf colour images obtained from a digital scanner that requires minimal calibration compared as it has its one light source and the angle and distance between light and leaf are constant. Our new algorithm produced superior correlations with the true value of foliar chlorophyll content measured in the laboratory compared with existing non-destructive methods when applied to three different species (lettuce, broccoli and tomato).

Ali, M.M., Al-Ani, A., Eamus, D. & Tan, D.K. 2012, 'A New Image-Processing-Based Technique for Measuring Leaf Dimensions', American-Eurasian J. Agric. & Environ. Sci., vol. 12, no. 12, pp. 1588-1594.
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We propose in this paper a new method for measuring a number of leaf dimension parameters including height, width, average width, perimeter and area. A digital scanner is utilized to acquire leaf images, which unlike digital cameras, requires no calibration in terms of size and angle of the acquired images. Edge detection, filtering and thresholding algorithms are applied to identify the leaf section of the image against the background. Forty leaves that differ in shape and size were used to validate the estimated parameters against the true values and parameters produced by the popular Li-Cor 3100. Data indicated that the proposed method achieved a constantly high accuracy

Barton, C., Duursma, R.A., Medlyn, B.E., Ellsworth, D.S., Eamus, D., Tissue, D., Adams, M.A., Conroy, J.P., Crous, K.Y., Liberloo, M., Low, M., Linder, S. & McMurtrie, R.E. 2012, 'Effects of elevated atmospheric [CO2] on instantaneous transpiration efficiency at leaf and canopy scales in Eucalyptus saligna', Global Change Biology, vol. 18, no. 2, pp. 585-595.
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Rising atmospheric concentrations of CO2 (Ca) can reduce stomatal conductance and transpiration rate in trees, but the magnitude of this effect varies considerably among experiments. The theory of optimal stomatal behaviour predicts that the ratio of pho

Li, L., Wang, Y., Yu, Q., Pak, B., Eamus, D., Yan, J., van Gorsel, E. & Baker, I.T. 2012, 'Improving the responses of the Australian community land surface model (CABLE) to seasonal drought', Journal of Geophysical Research, vol. 117, p. G04002.
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Correct representations of root functioning, such as root water uptake and hydraulic redistribution, are critically important for modeling the responses of vegetation to droughts and seasonal changes in soil moisture content. However, these processes are poorly represented in global land surface models. In this study, we incorporated two root functions: a root water uptake function which assumes root water uptake efficiency varies with rooting depth, and a hydraulic redistribution function into a global land surface model, CABLE. The water uptake function developed by Lai and Katul (2000) was also compared with the default one (see Wang et al., 2010) that assumes that efficiency of water uptake per unit root length is constant. Using eddy flux measurements of CO2 and water vapor fluxes at three sites experiencing different patterns of seasonal changes in soil water content, we showed that the two root functions significantly improved the agreement between the simulated fluxes of net ecosystem exchange and latent heat flux and soil moisture dynamics with those observed during the dry season while having little impact on the model simulation during the wet seasons at all three sites. Sensitivity analysis showed that varying several model parameters influencing soil water dynamics in CABLE did not significantly affect the model's performance. We conclude that these root functions represent a valuable improvement for land surface modeling and should be implemented into CABLE and other land surface models for studying carbon and water dynamics where rainfall varies seasonally or interannually.

Yunusa, I.A., Loganathan, P., Nissanka, S.P., Manoharan, V., Burchett, M., Skilbeck, C.G. & Eamus, D. 2012, 'Application of coal fly ash in agriculture: A strategic perspective', Critical Reviews in Environmental Science and Technology, vol. 42, no. 6, pp. 559-600.
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Fly ash is a major waste of coal-power generation and its management is a major environmental and economic challenge, and it will become even more critical with a projected increase in the reliance on coal for power generation. The authors discuss how th

Yunusa, I.A., Zolfaghar, S., Zeppel, M.J., Li, Z., Palmer, A. & Eamus, D. 2012, 'Fine root biomass and its relationship to evapotranspiration in woody and grassy vegetation covers for ecological restoration of waste storage and mining landscapes', Ecosystems, vol. 15, no. 1, pp. 113-127.
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Production and distribution of fine roots (<= 2.0 mm diameter) are central to belowground ecological processes. This is especially true where vegetation serves as a pump to prevent saturation of soil and possible drainage of excess water into or from potentially toxic waste material stored underground or in mounds aboveground. In this study undertaken near Sydney in Australia, we determined fine root biomass and evapotranspiration (ET) on a waste disposal site restored with either a 15-year-old grass sward or plantations of mixed woody species that were either 5 years old (plantation-5) with a vigorous groundcover of pasture legumes and grasses, or 3 years old (plantation-3) with sparse groundcover. These sites were compared with nearby remnant woodland; all four were located within 0.5-km radius at the same site. Ranking of fine root biomass was in the order woodland (12.3 Mg ha(-1)) > plantation-5 (8.3 Mg ha(-1)) > grass (4.9 Mg ha(-1)) > plantation-3 (1.2 Mg ha(-1)) and was not correlated with nutrient contents in soil or plants, but reflected the form and age of the vegetation covers. Trends in root length density (RLD) and root area index (RAI) followed those in root biomass, but the differences in RAI were larger than those in biomass amongst the vegetation covers. Annual ET in the dry year of 2009 was similar in the three woody vegetation covers (652-683 mm) and was at least 15% larger than for the grass (555 mm), which experienced restrained growth in winter and periodic mowing. This resulted in drainage from the grass cover while there was no drainage from any of the woody vegetation covers.

Zhao, C., Liu, C., Xia, J., Zhang, Y., Yu, Q. & Eamus, D. 2012, 'Recognition of key regions for restoration of phytoplankton communities in the Huai River basin, China', Journal Of Hydrology, vol. 420-421, pp. 292-300.
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Healthy phytoplankton communities are the basis of healthy water ecosystems, and form the foundation of many freshwater food webs. Globally many freshwater ecosystems are degraded because of intensive human activities, so water ecosystem restoration is a

Zhao, Z., Eamus, D., Yu, Q., Li, Y., Yang, H. & Li, J. 2012, 'Climate constraints on growth and recruitment patterns of Abies faxoniana over altitudinal gradients in the Wanglang Natural Reserve, eastern Tibetan Plateau', Australian Journal Of Botany, vol. 60, no. 7, pp. 602-614.
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The radial growth and recruitment patterns of trees in subalpine areas are subject to the influence of changing environmental conditions associated with changes in elevation. To investigate responses of fir radial growth and recruitment to climate factors at different elevations, tree-ring width chronologies and age structures of Abies faxoniana were developed from five sampling sites at ~2800+3300 m elevation on the north-western and south-eastern aspects in the Wanglang Natural Reserve on the eastern edge of Tibetan Plateau. Statistical characteristics of the chronologies indicated that expressed population signal and signal-to-noise ratio increased with increasing elevation in the north-western aspect; the reverse was observed on the south-eastern aspect. Correlation analysis between chronologies and climate variables showed that fir radial growth was negatively correlated with previous growing season mean temperatures and was positively correlated with January precipitation in all plots. The amount of precipitation in the growing season (June and July) greatly influenced radial growth in the two lower sites of both the aspects. The three plots on the north-western aspect were characterised by significant rates of tree recruitment in the past five decades.

Barton, C., Duursma, R., Medlyn, B.E., Ellsworth, D.S., Eamus, D., Tissue, D., Adams, M.A., Conroy, J.P., Crous, K., Liberloo, M., Low, M., Linder, S. & McMurtrie, R.E. 2011, 'Effects of elevated atmospheric (CO2) on instantaneous transpiration efficiency at leaf and canopy scales in Eucalyptus saligna', Global Change Biology, vol. 17.
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Rising atmospheric concentrations of CO2 (Ca) can reduce stomatal conductance and transpiration rate in trees, but the magnitude of this effect varies considerably among experiments. The theory of optimal stomatal behaviour predicts that the ratio of photosynthesis to transpiration (instantaneous transpiration efficiency, ITE) should increase in proportion to Ca. We hypothesized that plants regulate stomatal conductance optimally in response to rising Ca. We tested this hypothesis with data from young Eucalyptus saligna Sm. trees grown in 12 climate-controlled whole-tree chambers for 2 years at ambient and elevated Ca. Elevated Ca was ambient + 240 ppm, 60% higher than ambient Ca. Leaf-scale gas exchange was measured throughout the second year of the study and leaf-scale ITE increased by 60% under elevated Ca, as predicted. Values of leaf-scale ITE depended strongly on vapour pressure deficit (D) in both CO2 treatments. Whole-canopy CO2 and H2O fluxes were also monitored continuously for each chamber throughout the second year. There were small differences in D between Ca treatments, which had important effects on values of canopy-scale ITE. However, when Ca treatments were compared at the same D, canopy-scale ITE was consistently increased by 60%, again as predicted. Importantly, leaf and canopy-scale ITE were not significantly different, indicating that ITE was not scale-dependent. Observed changes in transpiration rate could be explained on the basis that ITE increased in proportion to Ca. The effect of elevated Ca on photosynthesis increased with rising D. At high D, Ca had a large effect on photosynthesis and a small effect on transpiration rate. At low D, in contrast, there was a small effect of Ca on photosynthesis, but a much larger effect on transpiration rate. If shown to be a general response, the proportionality of ITE with Ca will allow us to predict the effects of Ca on transpiration rate.

Duursma, R.A., Barton, C., Eamus, D., Medlyn, B.E., Ellsworth, D.S., Forster, M.A., Tissue, D., Linder, S. & McMurtrie, R.E. 2011, 'Rooting depth explains [CO2] x drought interaction in Eucalyptus saligna', Tree Physiology, vol. 31, no. 9 Special Issue, pp. 922-931.
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Elevated atmospheric [CO2] (eC(a)) often decreases stomatal conductance, which may delay the start of drought, as well as alleviate the effect of dry soil on plant water use and carbon uptake. We studied the interaction between drought and eC(a) in a whole-tree chamber experiment with Eucalyptus saligna. Trees were grown for 18 months in their C-a treatments before a 4-month dry-down. Trees grown in eC(a) were smaller than those grown in ambient C-a (aC(a)) due to an early growth setback that was maintained throughout the duration of the experiment. Pre-dawn leaf water potentials were not different between C-a treatments, but were lower in the drought treatment than the irrigated control. Counter to expectations, the drought treatment caused a larger reduction in canopy-average transpiration rates for trees in the eC(a) treatment compared with aC(a). Total tree transpiration over the dry-down was positively correlated with the decrease in soil water storage, measured in the top 1.5 m, over the drying cycle; however, we could not close the water budget especially for the larger trees, suggesting soil water uptake below 1.5 m depth. Using neutron probe soil water measurements, we estimated fractional water uptake to a depth of 4.5 m and found that larger trees were able to extract more water from deep soil layers. These results highlight the interaction between rooting depth and response of tree water use to drought. The responses of tree water use to eC(a) involve interactions between tree size, root distribution and soil moisture availability that may override the expected direct effects of eC(a). It is essential that these interactions be considered when interpreting experimental results.

Macinnis-Ng, C.M., Zeppel, M.J., Williams, M. & Eamus, D. 2011, 'Applying a SPA model to examine the impact of climate change on GPP of open woodlands and the potential for woody thickening', Ecohydrology, vol. 4, no. 3, pp. 379-393.
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Woody thickening is a global phenomenon that influences landscape C density, regional ecohydrology and biogeochemical cycling. The aim of the work described here is to test the hypothesis that increased atmospheric CO2 concentration, with or without photosynthetic acclimation, can increase gross primary production (GPP) and that this can explain woody thickening. We examine mechanisms underlying the response of GPP and highlight the importance of changes in soil water content by applying a detailed soil-plant-atmosphere model. Through this model, we show that CO2 enrichment with decreased or increased D and photosynthetic acclimation results in decreased canopy water use because of reduced gs. The decline in water use coupled with increased photosynthesis resulted in increased GPP, water-use efficiency and soil moisture content. This study shows that this is a valid mechanism for GPP increase because of CO2 enrichment coupled with either a decrease or an increase in D, in water-limited environments. We also show that a large increase in leaf area index could be sustained in the future as a result of the increased soil moisture content arising from CO2 enrichment and this increase was larger if D decreases rather than increases in the future. Large-scale predictions arising from this simple conceptual model are discussed and found to be supported in the literature. We conclude that woody thickening in Australia and probably globally can be explained by the changes in landscape GPP and soil moisture balance arising principally from the increased atmospheric CO2 concentration.

Medlyn, B.E., Duursma, R., Eamus, D., Ellsworth, D.S., Prentice, I., Barton, C., Crous, K., De Angelis, P., Freeman, M. & Wingate, L. 2011, 'Reconciling the optimal and empirical approaches to modelling stomatal conductance', Global Change Biology, vol. 17, no. 6, pp. 2134-2144.
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Models of vegetation function are widely used to predict the effects of climate change on carbon, water and nutrient cycles of terrestrial ecosystems, and their feedbacks to climate. Stomatal conductance, the process that governs plant water use and carbon uptake, is fundamental to such models

Whitley, R.J., Macinnis-Ng, C.M., Hutley, L.B., Beringer, J., Zeppel, M.J., Williams, M., Taylor, D.T. & Eamus, D. 2011, 'Is productivity of mesic savannas light limited or water limited? Results of a simulation study', Global Change Biology, vol. 17, no. 10, pp. 3130-3149.
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A soil-plant-atmosphere model was used to estimate gross primary productivity (GPP) and evapotranspiration (ET) of a tropical savanna in Australia. This paper describes model modifications required to simulate the substantial C4 grass understory together with C3 trees. The model was further improved to include a seasonal distribution of leaf area and foliar nitrogen through 10 canopy layers. Model outputs were compared with a 5-year eddy covariance dataset. Adding the C4 photosynthesis component improved the model efficiency and root-mean-squared error (RMSE) for total ecosystem GPP by better emulating annual peaks and troughs in GPP across wet and dry seasons. The C4 photosynthesis component had minimal impact on modelled values of ET. Outputs of GPP from the modified model agreed well with measured values, explaining between 79% and 90% of the variance and having a low RMSE (0.003-0.281 g C m(-2) day(-1)). Approximately, 40% of total annual GPP was contributed by C4 grasses. Total (trees and grasses) wet season GPP was approximately 75-80% of total annual GPP. Light-use efficiency (LUE) was largest for the wet season and smallest in the dry season and C4 LUE was larger than that of the trees. A sensitivity analysis of GPP revealed that daily GPP was most sensitive to changes in leaf area index (LAI) and foliar nitrogen (N-f) and relatively insensitive to changes in maximum carboxylation rate (V-cmax), maximum electron transport rate (J(max)) and minimum leaf water potential (Psi(min)). The modified model was also able to represent daily and seasonal patterns in ET, (explaining 68-81% of variance) with a low RMSE (0.038-0.19 mm day(-1)). Current values of N-f, LAI and other parameters appear to be colimiting for maximizing GPP. By manipulating LAI and soil moisture content inputs, we show that modelled GPP is limited by light interception rather than water availability at this site.

Yunusa, I.A., Fuentes, S., Palmer, A., Macinnis-Ng, C.M., Zeppel, M.J. & Eamus, D. 2011, 'Latent Heat Fluxes During Two Contrasting Years From A Juvenile Plantation Established Over A Waste Disposal Landscape', Journal Of Hydrology, vol. 399, no. 1-2, pp. 48-56.
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Revegetation to restore hydrological function to highly disturbed landscapes used for waste disposal or mining is often constrained by the initial low rates of water-use during the early phases of the developing vegetation. This problem is especially pronounced for revegetation that relies on trees due to their prolonged lead-time to achieve canopy closure. Initial low rates of water-use can however be overcome if a groundcover of quick-growing herbaceous species is planted first. To demonstrate the significance of groundcover in the early phase of revegetation, we undertook an energy balance analysis using the Bowen ratio technique for a juvenile plantation growing over a heavy groundcover of herbaceous species on a waste disposal site in 2006/2007 and 2007/2008. Latent heat flux (kE) from the landscape (trees plus groundcover and soil) fluctuated widely between 0.5 and 22 MJ m 2 d 1 and accounted for between 60% and 90% of available energy at the site; this percentage exceeded 100% during periods with significant advection.

Yunusa, I.A., Manoharan, V., Odeh, I., Shrestha, S., Skilbeck, C.G. & Eamus, D. 2011, 'Structural And Hydrological Alterations Of Soil Due To Addition Of Coal Fly Ash', Journal of Soils Sediments, vol. 11, no. 3, pp. 423-431.
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We tested the potential of using coal fly ash for improving the physical and hydrological characteristics of coarse and medium-textured agricultural soils. Acidic (FWA) and alkaline (FNSW) fly ashes were used to amend a range of representative agricultural soils. In the first experiment, fly ash was applied to the top 10 cm of 1-m long intact cores of a sandy loam soil at rates of 0, 12, 36 or 108 Mg/ha and sown with canola; after harvest, bulk density (BD), aggregate stability and mean weight diameter (MWD) were measured on the soil. In the second experiment, we assessed water retention at field capacity (-300 kPa) and permanent wilting point (-1,500 kPa) for sandy and loamy soils amended with FNSW at 0.0-16% (w/w). The third experiment used rainfall simulation to assess erodibility of sandy and loamy soils mixed with FNSW at rates of 0, 5 or 20 Mg/ha.

Zeppel, M.J., Lewis, J.D., Medlyn, B.E., Barton, C., Duursma, R., Eamus, D., Adams, M.A., Phillips, N., Elsworth, D.S., Forster, M.A. & Tissue, D. 2011, 'Interactive effects of elevated CO2 and drought on nocturnal water fluxes in Eucalyptus saligna', Tree Physiology, vol. 31, no. 9, pp. 932-944.
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Nocturnal water flux has been observed in trees under a variety of environmental conditions and can be a significant contributor to diel canopy water flux. Elevated atmospheric CO 2 (elevated [CO 2]) can have an important effect on day-time plant water fluxes, but it is not known whether it also affects nocturnal water fluxes. We examined the effects of elevated [CO 2] on nocturnal water flux of field-grown Eucalyptus saligna trees using sap flux through the tree stem expressed on a sapwood area (J s) and leaf area (E t) basis. After 19 months growth under well-watered conditions, drought was imposed by withholding water for 5 months in the summer, ending with a rain event that restored soil moisture. Reductions in J s and E t were observed during the severe drought period in the dry treatment under elevated [CO 2], but not during moderate- and post-drought periods. Elevated [CO 2] affected night-time sap flux density which included the stem recharge period, called 'total night flux' (19:00 to 05:00, J s,r), but not during the post-recharge period, which primarily consisted of canopy transpiration (23:00 to 05:00, J s,c). Elevated [CO 2] wet (EW) trees exhibited higher J s,r than ambient [CO 2] wet trees (AW) indicating greater water flux in elevated [CO 2] under well-watered conditions. However, under drought conditions, elevated [CO 2] dry (ED) trees exhibited significantly lower J s,r than ambient [CO 2] dry trees (AD), indicating less water flux during stem recharge under elevated [CO 2]. J s,c did not differ between ambient and elevated [CO 2]. Vapour pressure deficit (D) was clearly the major influence on night-time sap flux. D was positively correlated with J s,r and had its greatest impact on J s,r at high D in ambient [CO 2]. Our results suggest that elevated [CO 2] may reduce night-time water flux in E. saligna when soil water content is low and D is high. While elevated [CO 2] affected J s,r, it did not affect day-time water flux in wet soil, suggesting t at the responses of J s,r to environmental factors cannot be directly inferred from day-time patterns. Changes in J s,r are likely to influence pre-dawn leaf water potential, and plant responses to water stress. Nocturnal fluxes are clearly important for predicting effects of climate change on forest physiology and hydrology

Barton, C., Ellsworth, D.S., Medlyn, B.E., Duursma, R., Tissue, D., Adams, M., Eamus, D., Conroy, J.P., McMurtrie, R.E., Parsby, J. & Linder, S. 2010, 'Whole-Tree Chambers For Elevated Atmospheric Co2 Experimentation And Tree Scale Flux Measurements In South-Eastern Australia: The Hawkesbury Forest Experiment', Agricultural And Forest Meteorology, vol. 150, no. 7-8, pp. 941-951.
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Resolving ecophysiological processes in elevated atmospheric CO2 (C-a) at scales larger than single leaves poses significant challenges. Here, we describe a field-based experimental system designed to grow trees up to 9m tall in elevated C-a with the cap

Macinnis-Ng, C.M., Fuentes, S., O'Grady, A.P., Palmer, A., Taylor, D.T., Whitley, R.J., Yunusa, I.A., Zeppel, M.J. & Eamus, D. 2010, 'Root Biomass Distribution And Soil Properties Of An Open Woodland On A Duplex Soil', Plant And Soil, vol. 327, no. 1-2, pp. 377-388.
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Data on the distribution of root biomass are critical to understanding the ecophysiology of vegetation communities. This is particularly true when models are applied to describe ecohydrology and vegetation function. However, there is a paucity of such in

Veeragathipillai, M., Yunusa, I.A., Loganathan, P., Lawrie, R., Skilbeck, C.G., Burchett, M., Murray, B.R. & Eamus, D. 2010, 'Assessments of Class F fly ashes for amelioration of soil acidity and their influence on growth and uptake of Mo and Se by canola', Fuel, vol. 89, no. 11, pp. 3498-3504.
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Coal fly ash can be used to ameliorate productivity constraints in agricultural soils, but their efficacy still remains highly variable. To ascertain the capacity of Class F fly ashes to modify pH of acidic soils, and their effects on the yield and uptake of molybdenum (Mo) and selenium (Se) by canola (Brassica napus L.), we applied two acidic and two alkaline Class F ashes at rates equivalent to 0, 12, 36, and 108 Mg/ ha to the top layer (0Ô++10 cm) of 100 cm long intact cores of acidic sandy clay and clay loam soils. Only the alkaline ash which had the highest calcium carbonate equivalent (2.43%) increased the pH of the top 10 cm of the sandy clay soil. However, this ash was also highly saline and when applied at P36 Mg/ha it increased the electrical conductivity in the top soil layer. Increases in soil pH as a result of alkaline ash addition also elevated concentrations of Se in the plant shoot. The ashes with high concentrations of Mo and Se generally increased uptake of these elements in the plant shoot and/or seed. When these ashes were applied at 108 Mg/ha they increased the concentrations of these elements in the treated topsoil.

Veeragathipillai, M., Yunusa, I.A., Loganathan, P., Lawrie, R., Murray, B.R., Skilbeck, C.G. & Eamus, D. 2010, 'Boron contents and solubility in Australian fly ashes and its uptake by canola (Brassica napus L.) from the ash-amended soils', Australian Journal of Soil Research, vol. 48, no. 5, pp. 480-487.
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Phytotoxicity due to excessive boron (B) uptake by plants impedes routine agronomic utilisation of coal fly ash. We assessed 11 fly ashes (pH 3.14Ô++10.77) having total B content (Bt) of 12Ô++136 mg/kg, of which 20Ô++30% was hot water soluble (Bs) in the acidic ashes (pH <5) and 5Ô++10% in the alkaline ashes, for their potential to supply B to plants and their risk associated with phytotoxicity. We found the Bs/Bt to be negatively correlated (R2 = 0.63**, N = 11) with ash pH. We conducted two trials in which canola was grown in soils amended with fly ash. In the first trial, an alkaline fly ash (Bt 66 mg/kg) was incorporated at 5 rates of up to 625 Mg/ha into the top 50mm of 2 acidic soils in 0.30-m-long intact cores, and sown with canola. Boron concentration in leaves at flowering reached the phytotoxic threshold, and both plant growth and seed yield were reduced, only at 625 Mg/ha. In the second trial, 4 fly ashes (pH 3.29Ô++10.77, Bt 12Ô++127 mg/kg) were incorporated at 4 rates of up to 108 Mg/ha into the top 0.10mof 2 acidic soils in 1.0-m-long intact cores and then sown with canola. Ashes with highest Bt, when applied at 108 Mg/ha, increased B concentration in the topsoil only. Of the 2 ashes with the highest Bt, only that which produced low soil pH and applied at 108 Mg/ha increased B concentration in the shoot, but was still below phytotoxic threshold. The results suggest that B derived from these ashes may not cause phytotoxicity and excessive soil B accumulation if the ashes are applied at modest rates (<36 Mg/ha) to the topsoil layers.

Palmer, A., Fuentes, S., Taylor, D.T., Macinnis-Ng, C.M., Zeppel, M.J., Yunusa, I.A. & Eamus, D. 2010, 'Towards A Spatial Understanding Of Water Use Of Several Land-Cover Classes: An Examination Of Relationships Amongst Pre-Dawn Leaf Water Potential, Vegetation Water Use, Aridity And Modis Lai', Ecohydrology, vol. 3, no. 1, pp. 1-10.
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Leaf area index (LAI) is a key physical variable which controls the exchange of water and CO, between the earth and the atmosphere. Recent improvements in the quality of satellite-derived estimates of LAI, specifically the MODIS LAI product, have led to

Yunusa, I.A., Zeppel, M.J., Fuentes, S., Macinnis-Ng, C.M., Palmer, A. & Eamus, D. 2010, 'An Assessment Of The Water Budget For Contrasting Vegetation Covers Associated With Waste Management', Hydrological Processes, vol. 24, no. 9, pp. 1149-1158.
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Revegetation is critical to restoring hydrological function on waste disposal sites in order to minimize runoff and drainage and safeguard the water quality of the catchment. In this study, we determined the components of soil-water balance between late

Yunusa, I.A., Aumann, C., Rab, M.A., Merrick, N.P., Fisher, P.R., Eberbach, P. & Eamus, D. 2010, 'Topographical And Seasonal Trends In Transpiration By Two Co-Occurring Eucalyptus Species During Two Contrasting Years In A Low Rainfall Environment', Agricultural and Forest Meteorology, vol. 150, no. 9, pp. 1234-1244.
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Understanding the strategies that confer resilience on natural woodlands in drought prone environments is important for the conservation of these and similar ecosystems. Our main aim in this 2-year study was to assess traits (sapwood area, sapwood densit

Zeppel, M.J., Tissue, D., Taylor, D.T., Macinnis-Ng, C.M. & Eamus, D. 2010, 'Rates Of Nocturnal Transpiration In Two Evergreen Temperate Woodland Species With Differing Water-Use Strategies', Tree Physiology, vol. 30, no. 8, pp. 988-1000.
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Nocturnal fluxes may be a significant factor in the annual water budget of forested ecosystems. Here, we assessed sap flow in two co-occurring evergreen species (Eucalyptus parramattensis and Angophora bakeri) in a temperate woodland for 2 years in order

O'Grady, A.P., Cook, P., Eamus, D., Duguid, A., Wischusen, J., Fass, T. & Worldege, D. 2009, 'Convergence of tree water use within an arid-zone woodland', Oecologia, vol. 160, no. 4, pp. 643-655.
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We examined spatial and temporal patterns of tree water use and aspects of hydraulic architecture in four common tree species of central Australia-Corymbia opaca, Eucalyptus victrix, E. camaldulensis and Acacia aneura-to better understand processes that constrain water use in these environments. These four widely distributed species occupy contrasting niches within arid environments including woodlands, floodplains and riparian environments. Measurements of tree water use and leaf water potential were made at two sites with contrasting water table depths during a period of high soil water availability following summer rainfall and during a period of low soil water availability following 7 months of very little rainfall during 2007. There were significant differences in specific leaf area (SLA), sapwood area to leaf area ratios and sapwood density between species. Sapwood to leaf area ratio increased in all species from April to November indicating a decline in leaf area per unit sapwood area. Despite very little rainfall in the intervening period three species, C. opaca, E. victrix and E. camaldulensis maintained high leaf water potentials and tree water use during both periods. In contrast, leaf water potential and water use in the A. aneura were significantly reduced in November compared to April. Despite contrasting morphology and water use strategies, we observed considerable convergence in water use among the four species. Wood density in particular was strongly related to SLA, sapwood area to leaf area ratios and soil to leaf conductance, with all four species converging on a common relationship. Identifying convergence in hydraulic traits can potentially provide powerful tools for scaling physiological processes in natural ecosystems.

Whitley, R.J., Medlyn, B.E., Zeppel, M.J., Macinnis-Ng, C.M. & Eamus, D. 2009, 'Comparing the Penman-Monteith equation and a modified Jarvis-Stewart model with an artificial neural network to estimate stand-scale transpiration and canopy conductance', Journal Of Hydrology, vol. 373, no. 1-2, pp. 256-266.
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The responses of canopy conductance to variation in solar radiation, vapour pressure deficit and soil moisture have been extensively modelled using a Jarvis-Stewart (JS) model. Modelled canopy conductance has then often been used to predict transpiration using the Penman-Monteith (PM) model. We previously suggested an alternative approach in which the JS model is modified to directly estimate transpiration rather than canopy conductance. In the present study we used this alternative approach to model tree water fluxes from an Australian native forest over an annual cycle. For comparative purposes we also modelled canopy conductance and estimated transpiration via the PM model. Finally we applied an artificial neural network as a statistical benchmark to compare the performance of both models. Both the PM and modified JS models were parameterised using solar radiation, vapour pressure deficit and soil moisture as inputs with results that compare well with previous studies. Both models performed comparably well during the summer period. However, during winter the PM model was found to fail during periods of high rates of transpiration. In contrast, the modified JS model was able to replicate observed sapflow measurements throughout the year although it too tended to underestimate rates of transpiration in winter under conditions of high rates of transpiration. Both approaches to modelling transpiration gave good agreement with hourly, daily and total sums of sapflow measurements with the modified JS and PM models explaining 87% and 86% of the variance, respectively. We conclude that these three approaches have merit at different time-scales.

Yunusa, I.A., Burchett, M., Veeragathipillai, M., DeSilva, L., Eamus, D. & Skilbeck, C.G. 2009, 'Photosynthetic Pigment Concentrations, Gas Exchange and Vegetative Growth for Selected Monocots and Dicots Treated with Two Contrasting Coal Fly Ashes', Journal of Environmental Quality, vol. 38, no. 4, pp. 1466-1472.
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There is uncertainty as to the races of coal fly ash needed for optimum physiological processes and growth. In the current study we tested the hyothesis that photosynthetic pigments concentrations and CO2 assimilation (A) are more sensitive than dry weights in plants grown on media amended with coal fly ash. We applied the Terrestrial Plant Growth Test (Guideline 208) protocols of the Organization for Economic Cooperation and Development (OECD) to monocots [barley (Hordeum vulgare) and ryegrass (Secale cereale)] and dicots [canola (Brasica napus), radish (Raphanus sativus), field peas (Pisum sativum), and lucerne (Medicago sativa)] on media amended with fly ashes derived from semi-bituminous (gray ash) or lignite (red ash) coals at rates of 0, 2.5, 5.0, 10, or 20 Mg ha(-1). The red ash had higher elemental concentrations and salinity than the gray ash. Fly ash addition had no significant effect on germination by any of the six species. At moderate rates (<= 10 Mg ha(-1)) both ashes increased (P < 0.05) growth rates and concentrations of chlorophylls a and b, but reduced carotenoid concentrations. Addition of either ash increased A in radish and transpiration in barley Growth rates and final dry weights were reduced for all of the six test species when addition rates exceeded 10 Mg ha(-1) for gray ash and 5 Mg ha(-1) for red ash. We concluded that plant dry weights, rather than pigment concentrations and/or instantaneous rates of photosynthesis, are more consistent for assessing subsequent growth in plants Supplied with fly ash. Copyright (C) 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher.

Eamus, D., Taylor, D.T., Macinnis-Ng, C.M., Shanahan, S. & De Silva, D.L. 2008, 'Comparing model predictions and experimental data for the reponse of stomatal conductance and guard cell turgor to manipulations of cuticular conductance, leaf-to-air vapour pressure difference and temperature: feedback mechanisms are able to account', Plant, Cell and Environment, vol. 31, no. 3, pp. 269-277.
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Stomata respond to increasing leaf-to-air vapour pressure difference (LAVPD) ( D) by closing. The mechanism by which this occurs is debated. A role for feedback and peristomatal transpiration has been proposed. In this paper, we apply a recent mechanistic model of stomatal behaviour, and compare model and experimental data for the influence of increasing D on stomatal conductance. We manipulated cuticular conductance ( g_c) by three independent methods. First, we increased g_c by using a solvent mixture applied to both leaf surfaces prior to determining stomatal responses to D; second, we increased g_c by increasing leaf temperature at constant D; and third, we coated a small area of leaf with a light oil to decrease g_c. In all three experiments, experimental data and model outputs showed very close agreement. We conclude, from the close agreement between model and experimental data and the fact that manipulations of g_c, and hence cuticular transpiration, influenced g_s in ways consistent with a feedback mechanism, that feedback is central in determining stomatal responses to D

Fuentes, S., Palmer, A., Taylor, D.T., Zeppel, M.J., Whitley, R.J. & Eamus, D. 2008, 'An automated procedure for estimating the leaf area index (LAI) of woodland ecosystems using digital imagery, MATLAB programming and its application to an examination of the relationship between remotely sensed and field measurements of LAI.', Functional Plant Biology, vol. 35, no. 9-10, pp. 1070-1079.
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Leaf area index (LAI) is one of the most important variables required for modelling growth and water use of forests. Functional-structural plant models use these models to represent physiological processes in 3-D tree representations. Accuracy of these models depends on accurate estimation of LAI at tree and stand scales for validation purposes. A recent method to estimate LAI from digital images (LAI(D)) uses digital image capture and gap fraction analysis (Macfarlane et al. 2007b) of upward-looking digital photographs to capture canopy LAI(D) (cover photography). After implementing this technique in Australian evergreen Eucalyptus woodland, we have improved the method of image analysis and replaced the time consuming manual technique with an automated procedure using a script written in MATLAB7.4 (LAI(M)). Furthermore, we used this method to compare MODIS LAI values with LAI(D) values for a range of woodlands in Australia to obtain LAI at the forest scale. Results showed that the MATLAB script developed was able to successfully automate gap analysis to obtain LAI(M). Good relationships were achieved when comparing averaged LAI(D) and LAI(M) (LAI(M) = 1.009-0.0066 LAI(D); R(2) = 0.90) and at the forest scale, MODIS LAI compared well with LAI(D) (MODIS LAI = 0.9591 LAI(D)-0.2371; R(2) = 0.89). This comparison improved when correcting LAI(D) with the clumping index to obtain effective LAI (MODIS LAI = 1.0296 LAI(e) + 0.3468; R(2) = 0.91). Furthermore, the script developed incorporates a function to connect directly a digital camera, or high resolution webcam, from a laptop to obtain cover photographs and LAI analysis in real time. The later is a novel feature which is not available on commercial LAI analysis softwares for cover photography. This script is available for interested researchers.

Grigg, A., MacFarlane, C., Evangelista, C., Eamus, D. & Adams, M. 2008, 'Does initial spacing influence crown and hydraulic architecture of Eucalyptus marginata?', Tree Physiology, vol. 28, no. 5, pp. 753-760.
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Long-term declines in rainfall in south-western Australia have resulted in increased interest in the hydraulic characteristics of jarrah (Eucalyptus marginata Donn ex Smith) forest established in the region's drinking water catchments on rehabilitated ba

Leal, S., Eamus, D., Grabner, M., Wimmer, R. & Cherubini, P. 2008, 'Tree rings of Pinus nigra from the Vienna basin region (Austria) show evidence of change in climatic sensitivity in the late 20th century', Canadian Journal Of Forest Research-Revue Canadienne De Recherche Forestiere, vol. 38, no. 4, pp. 744-759.
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The width of tree rings of Pinus nigra Arn. trees growing near the ecological limits for the species, in the Vienna basin, Austria, showed a strong and positive correlation with spring-summer precipitation, indicating a dependence of growth on water avai

Palmer, A., Fuentes, S., Taylor, D.T., Macinnis-Ng, C.M., Zeppel, M.J., Yunusa, I.A., February, E. & Eamus, D. 2008, 'The use of pre-dawn leaf water potential and MODIS LAI to explore seasonal trends in the phenology of Australian and southern African woodlands and savannas', Australian Journal Of Botany, vol. 56, no. 7, pp. 557-563.
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Trends in global soil moisture are needed to inform models of soil+plant+atmosphere interactions. Predawn leaf water potential (?pd), a surrogate for soil moisture and an index of plant water stress, has been routinely collected in Australian forests, woodlands and savannas, but the associated leaf area index (LAI) has seldom been available to enable the preparation of a ?pd on LAI relationship. Following an analysis of ?pd and MODIS LAI data from Australian forests, woodlands and savannas, we identified patterns in ?pd which provide an understanding of the role of soil-moisture status in controlling LAI. In the savanna of northern Australia, the MODIS LAI product had a basal value of 0.96 during the dry season as compared with a mean value of 2.5 for the wet season. The dry season value is equivalent to the LAI of the tree component and corresponds with ground-truthed LAI. ?pd is lowest (more negative) during the height of the dry season (late October) at -2.5 MPa, and highest (-0.1 MPa) during the wet season (early March). We present two models which predict ?pd from the MODIS LAI product. These may be useful surrogates for studying trends in soil moisture in highly seasonal climates and may contribute to climate change research.

Pepper, D., McMurtrie, R.E., Medlyn, B.E., Keith, H. & Eamus, D. 2008, 'Mechanisms linking plant productivity and water status for a temperate Eucalyptus forest flux site: analysis over wet and dry years with a simple model', Functional Plant Biology, vol. 35, no. 6, pp. 493-508.
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A simple process-based model was applied to a tall Eucalyptus forest site over consecutive wet and dry years to examine the importance of different mechanisms linking productivity and water availability. Measured soil moisture, gas flux (CO2, H2O) and me

Taylor, D.T. & Eamus, D. 2008, 'Coordinating leaf functional traits with branch hydraulic conductivity: resource substitution and implications for carbon gain', Tree Physiology, vol. 28, no. 8, pp. 1169-1177.
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We Studied relationships among branch hydraulic conductivity, xylem embolism, stomatal conductance (g(s)), foliar nitrogen (N) concentration and specific leaf area (SLA) of seven tree species growing at four temperate woodland sites spanning a 464-1350 m

Whitley, R.J., Zeppel, M.J., Armstrong, N.G., Macinnis-Ng, C.M., Yunusa, I.A. & Eamus, D. 2008, 'A modified Jarvis-Stewart model for predicting stand-scale transpiration of an Australian native forest', Plant and Soil, vol. 305, no. 1-2, pp. 35-47.
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Rates of water uptake by individual trees in a native Australian forest were measured on the Liverpool Plains, New South Wales, Australia, using sapflow sensors. These rates were up-scaled to stand transpiration rate (expressed per unit ground area) using sapwood area as the scalar, and these estimates were compared with modelled stand transpiration. A modified Jarvis-Stewart modelling approach (Jarvis 1976), previously used to calculate canopy conductance, was used to calculate stand transpiration rate. Three environmental variables, namely solar radiation, vapour pressure deficit and soil moisture content, plus leaf area index, were used to calculate stand transpiration, using measured rates of tree water use to parameterise the model. Functional forms for the model were derived by use of a weighted non-linear least squares fitting procedure. The model was able to give comparable estimates of stand transpiration to those derived from a second set of sapflow measurements. It is suggested that short-term, intensive field campaigns where sapflow, weather and soil water content variables are measured could be used to estimate annual patterns of stand transpiration using daily variation in these three environmental variables. Such a methodology will find application in the forestry, mining and water resource management industries where long-term intensive data sets are frequently unavailable.

Yunusa, I.A., Veeragathipillai, M., DeSilva, L., Eamus, D., Murray, B.R. & Nissanka, S. 2008, 'Growth and elemental accumulation by canola on soil amended with coal fly ash', Journal Of Environmental Quality, vol. 37, no. 3, pp. 1263-1270.
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To explore the agronomic potential of an Australian coal fly ash, we conducted two glasshouse experiments in which we measured chlorophyll fluorescence, CO2 assimilation (A), transpiration, stomatal conductance, biomass accumulation, seed yield, and elem

Yunusa, I.A., Nuberg, I., Fuentes, S., Lu, P. & Eamus, D. 2008, 'A simple field validation of daily transpiration derived from sapflow using a porometer and minimal meteorological data', Plant And Soil, vol. 305, no. 1-2, pp. 15-24.
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Heat-pulse techniques are routinely used to estimate transpiration from canopies of woody plants typically without any local calibration, mainly because of the difficulty of doing so in the field and, frequently, lack of detailed weather data. This is de

Zeppel, M.J., Macinnis-Ng, C.M., Palmer, A., Taylor, D.T., Whitley, R.J., Fuentes, S., Yunusa, I.A., Williams, M. & Eamus, D. 2008, 'An analysis of the sensitivity of sap flux to soil and plant variables assessed for an Australian woodland using a soil-plant-atmosphere model', Functional Plant Biology, vol. 35, no. 6, pp. 509-520.
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Daily and seasonal patterns of tree water use were measured for the two dominant tree species, Angophora bakeri E.C.Hall (narrow-leaved apple) and Eucalyptus sclerophylla (Blakely) L.A.S. Johnson & Blaxell (scribbly gum), in a temperate, open, evergreen woodland using sap flow sensors, along with information about soil, leaf, tree and micro-climatological variables. The aims of this work were to: (a) validate a soil+plant+atmosphere (SPA) model for the specific site; (b) determine the total depth from which water uptake must occur to achieve the observed rates of tree sap flow; (c) examine whether the water content of the upper soil profile was a significant determinant of daily rates of sap flow; and (d) examine the sensitivity of sap flow to several biotic factors. It was found that: (a) the SPA model was able to accurately replicate the hourly, daily and seasonal patterns of sap flow; (b) water uptake must have occurred from depths of up to 3 m; (c) sap flow was independent of the water content of the top 80 cm of the soil profile; and (d) sap flow was very sensitive to the leaf area of the stand, whole tree hydraulic conductance and the critical water potential of the leaves, but insensitive to stem capacitance and increases in root biomass. These results are important to future studies of the regulation of vegetation water use, landscape-scale behaviour of vegetation, and to water resource managers, because they allow testing of large-scale management options without the need for large-scale manipulations of vegetation cover.

Zeppel, M.J. & Eamus, D. 2008, 'Co-ordination of leaf area, sapwood area and canopy conductance leads to species convergence of tree water use in a remnant evergreen woodland.', Australian Journal Of Botany, vol. 36, no. 2, pp. 97-108.
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This paper compares rates of tree water use, Huber value, canopy conductance and canopy decoupling of two disparate, co-occurring tree species, in a stand of remnant native vegetation in temperate Australia in order to compare their relative behaviour seasonally and during and after a drought. The study site was an open woodland dominated by Eucalyptus crebra F.Muell. (a broad-leaved species) and Callitris glaucophylla J.Thompson & L.A.S. Johnson (a needle-leaved tree species). Tree water use was measured with sapflow sensors and leaf area and sapwood area were measured destructively on felled trees. The Huber value was calculated as the ratio of sapwood area to leaf area. Diameter at breast height (DBH) of the stem was used as a measure of tree size. Canopy conductance was calculated with an inversion of the Penman+Monteith equation, whereas canopy decoupling) was calculated as described by Lu et al. (2003). The relationship between DBH and daily total water use varied during the four measurement periods, with largest rates of water use observed in summer 2003+2004, following a large rainfall event and the smallest maximum water use observed in winter 2003 when monthly rainfall was much less than the long-term mean for those months. Despite differences in the relationship between sapwood area and DBH for the two species, the relationship between daily total water use and DBH did not differ between species at any time. The same rates of water use for the two species across sampling periods arose through different mechanisms; the eucalypt underwent significant changes in leaf area whereas the Callitris displayed large changes in canopy conductance, such that tree water use remained the same for both species during the 2-year period.

Zeppel, M.J., Macinnis-Ng, C.M., Yunusa, I.A., Whitley, R.J. & Eamus, D. 2008, 'Long term trends of stand transpiration in a remnant forest during wet and dry years', Journal Of Hydrology, vol. 349, pp. 200-213.
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Daily and annual rates of stand transpiration in a drought year and a non-drought year are compared in order to understand the adaptive responses of a remnant woodland to drought and predict the effect of land use change. Two methods were used to estimat

Zeppel, M.J., Macinnis-Ng, C.M., Ford, C.R. & Eamus, D. 2008, 'The response of sap flow to pulses of rain in a temperate Australian woodland', Plant and Soil, vol. 305, no. 1-2, pp. 121-130.
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In water-limited systems, pulses of rainfall can trigger a cascade of plant physiological responses. However, the timing and size of the physiological response can vary depending on plant and environmental characteristics, such as rooting depth, plant size, rainfall amount, or antecedent soil moisture. We investigated the influence of pulses of rainfall on the response of sap flow of two dominant evergreen tree species, Eucalyptus crebra (a broadleaf) and Callitris glaucophylla (a needle leaved tree), in a remnant open woodland in eastern Australia. Sap flow data were collected using heat-pulse sensors installed in six trees of each species over a 2 year period which encompassed the tail-end of a widespread drought. Our objectives were to estimate the magnitude that a rainfall pulse had to exceed to increase tree water use (i.e., define the threshold response), and to determine how tree and environmental factors influenced the increase in tree water use following a rainfall pulse. We used data filtering techniques to isolate rainfall pulses, and analysed the resulting data with multivariate statistical analysis. We found that rainfall pulses less than 20 mm did not significantly increase tree water use (P>0.05). Using partial regression analysis to hold all other variables constant, we determined that the size of the rain event (P<0.05, R 2=0.59), antecedent soil moisture (P<0.05, R 2=0.29), and tree size (DBH, cm, P<0.05, R 2=0.15), all significantly affected the response to rainfall. Our results suggest that the conceptual Threshold-Delay model describing physiological responses to rainfall pulses could be modified to include these factors. We further conclude that modelling of stand water use over an annual cycle could be improved by incorporating the T-D behaviour of tree transpiration.

Jahansooz, M., Yunusa, I.A., Coventry, D., Palmer, A. & Eamus, D. 2007, 'Radiation- And Water-Use Associated With Growth And Yields Of Wheat And Chickpea In Sole And Mixed Crops', European Journal Of Agronomy, vol. 26, no. 3, pp. 275-282.
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A renewed interest in mixed cropping for its potential to boost yields through increased capture and use of solar radiation and soil-water by the component species. This led to the present study, in which we assessed the performance of wheat and chickpea

Kelley, G., O'Grady, A.P., Hutley, L.B. & Eamus, D. 2007, 'A comparison of tree water use in two contiguous vegetation communities of the seasonally dry tropics of northern Australia: the importance of site water budget to tree hydraulics', Australian Journal Of Botany, vol. 55, no. 7, pp. 700-708.
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Tree water use in two contiguous communities (eucalypt open-forest and Melaleuca paperbark forest) was measured in tropical Australia, over a 2-year period. The aims of the study were to (1) quantify daily and seasonal patterns of water use in each community, (2) compare patterns of water use among the communities and (3) compare relationships among tree size, sapwood area and water use within the two contrasting vegetation communities. Access to deep soil water stores and the effect of run-on from the eucalypt forest resulted in a relatively high pre-dawn water potential throughout the year, particularly for Melaleuca forest. There were no differences in daily rates of water use, expressed on a sapwood area (Q s) basis, between the two eucalypt species examined (Eucalyptus miniata Cunn. Ex Schauer and E. tetrodonta F.Muell) at any time in the eucalypt forest. For both the eucalypt and Melaleuca forests, there was less seasonal variation in water use expressed on a leaf area (Q l) basis than on a Q s basis, and neither year nor season were significant factors in Q l. In the mono-specific Melaleuca forest, Q s was not significantly different between years or seasons. Water use on a Q l basis was similarly not significantly different between years or seasons in the Melaleuca forest. Leaf area index (LAI) of the eucalypt forest was about half of that of the Melaleuca forest throughout the year but sapwood area per hectare was 33% larger in the eucalypt than the Melaleuca forest, despite the basal area of the Melaeuca forest being almost double that of the eucalypt forest.

MacFarlane, C., Hoffman, M.J., Eamus, D., Kerp, N., Higginson, S., McMurtrie, R.E. & Adams, M. 2007, 'Estimation of leaf area index in eucalypt forest using digital photography', Agricultural And Forest Meteorology, vol. 143, no. 3-4, pp. 176-188.
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We tested whether leaf area index (L) in eucalypt vegetation could be accurately estimated from gap fraction measurements made using both fisheye and non-fisheye digital photography. We compared methods that measure the gap fraction at a single zenith angles. We applied these methods in an unthinned stand of the broadleaf tree species Ecualyptus marginata that had an intial L of 3. We removed one-third of the trees and reapplied the methods, and then removed another one-third of the trees and applied the methods a tjird time. L from the photographic methods was compared to L obtained from destrictive sampling and allometry. We found that L was accurately estimated from non-fisheye images taken at the zenith, providing thaty the total gap fraction was divided into large, between-crown gaps and smaller, within-crown gaps, prior to using the Beer-Lambert law to estimate L. This rapid and simpel method corrected for foliage clumping and provided estimates of crown porosity, crown cover, foliage cover and the foliage clumping index at the zenith, but required an assumption about the lgiht extenction coefficient at the zenith. Fisheye photography also provided good estimates of L bit only if the images were corrected for the gamma function of the digital camera, and the combined Chen-Chilar and Lang-Xiang method of correcting for foliage prjection coefficient was. Method of obtaining and analysising gap fraction and gap size distributions from fisheye photography need further improvement to separate the effects of foliage clumping and leaf angle distribution.

MacFarlane, C., Arndt, S.K., Livesley, S., Edgar, A., White, D., Adams, M. & Eamus, D. 2007, 'Estimation of leaf area index in eucalypt forest with vertical foliage, using cover and fullframe fisheye photography', Forest Ecology And Management, vol. 242, no. 2-3, pp. 756-763.
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This study compared fullframe fisheye photography and cover photography with destructive leaf area index (L) estimation and the Licor LAI-2000 plant canopy analyser (PCA) in plantations of the vertical leaved species Eucalyptus globulus. Fullframe fisheye photography differs from circular fisheye photography in that the images have reduced field of view such that the zenithal range of 0-90 degrees extends to the corners of the rectangular image, roughly doubling image resolution compared to circular images. Cover images instead are obtained by pointing a 70mm equivalent focal length lens (in 35mm format) straight upwards. Measurements of cover and indirect estimates of plant area index (Lt) were made in 12 stands of 6-8 years old Eucalyptus glubulus. L was measured using destructive sampling and allometry in nine of these stands and ranged from 2.5 to 6.6. Both foliage cover and Lt from the PCA were well correlated with L from allometry, but fullframe fisheye photography provided poor estimates of L despite corrections fro foliage clumping. Sampling location had a significant effect on estimates of crown porosity, crown cover and zenithal clumping index from cover photography. The zenithal extinction coefficient (k), calculated from L, crown porosity and cover, ranged from 0.14 to 0.025 and appeared to decrease as L increased; hence, we were unable to obtain an unambiguous estimate of k for E. globulus stands. Nonetheless, the study showed that L can be estimated from foliage cover with similar certainty to that of the PCA. We conclude that the greatest challenge facing indirect estimation of L in forests using photographic methods is to separate the effects of foliage angle from those of foliage clumping.

Eamus, D., Froend, R., Loomes, R., Hose, G.C. & Murray, B.R. 2006, 'A functional methodology for determining the groundwater regime needed to maintain the health of groundwater-dependent vegetation', Australian Journal Of Botany, vol. 54, no. 2, pp. 97-114.
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In the past, the phrase environmental allocations of water has most often been taken to mean allocation of water to rivers. However, it is now accepted that groundwater-dependent ecosystems are an important feature of Australian landscapes and require an

Eamus, D. & Froend, R. 2006, 'Groundwater-dependent ecosystems the where, what and why of GDEs', Australian Journal Of Botany, vol. 54, no. 2, pp. 91-96.
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Murray, B.R., Hose, G.C., Eamus, D. & Licari, D.D. 2006, 'Valuation of groundwater-dependent ecosystems: a functional methodology incorporating ecosystem services', Australian Journal Of Botany, vol. 54, no. 2, pp. 221-229.
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Groundwater-dependent ecosystems (GDEs) are ecosystems that must have access to groundwater to maintain their ecological structure and function. Rapidly expanding numbers of humans are placing increased demands on groundwater for consumption, industry an

O'Grady, A.P., Eamus, D., Cook, P. & Lamontagne, S. 2006, 'Comparative water use by the riparian trees Melaleuca argentea and Corymbia bella in the wet-dry tropics of northern Australia', Tree Physiology, vol. 26, no. 2, pp. 219-228.
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We examined sources of water and daily and seasonal water use patterns in two riparian tree species occupying contrasting niches within riparian zones throughout the wet-dry tropics of northern Australia: Corymbia bella Hill and Johnson is found along th

O'Grady, A.P., Eamus, D., Cook, P. & Lamontagne, S. 2006, 'Groundwater use by riparian vegetation in the wet-dry tropics of northern Australia', Australian Journal of Botany, vol. 54, pp. 145-154.
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Within Australian and globally there is considerable concern about the potential impacts of groundwater extraction on ecosystems dependent on groundwater. In this study we have combined heat pulse and isotopic techniques to assess groundwater use by riparian vegetation along the Daly River in the Northern Territory. The riparian forests of the Daly River exhibited considerable structural and floristic complexity. More than 40 tress species were recorded during vegetation surveys and these exhibited a range of leaf phonologies, implying complex patterns of water resource partitioning within the riparian forests. Water use was afunction of species and season, and stand water use varied between 1.8 and 4.1 mm day-1. In general, however, water use tended to be igher in the wet season than suring the dry season, reflecting the contribution to stand water use bu dr-season deciduous tree sepcies. There was a strong relationship between stand basal area and stabd water use in the wet season, but the strength of this relationship was lower inthe dry season. The amount of groundwater use, as determined by analysis of deuterium concentrations in xylem sap, was principally a function of position in the landscape. Trees at lower elevations, closer to the river, used more groundwater than trees higher on the levees. By using a combination of techniques we showed that riparian vegetation along the Daly River was highly groundwater dependent and that these water-use requirements need to be considered in regional management plans for groundwater.

Yunusa, I.A., Eamus, D., De Silva, D.L., Murray, B.R., Burchett, M., Skilbeck, C.G. & Heidrich, C. 2006, 'Fly-ash: An exploitable resource for management of Australian agricultural soils', Fuel, vol. 85, no. 16, pp. 2337-2344.
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Agricultural soils in Australia have inherent limitations of structural and nutritional nature that pose major constraints to crop productivity. These soils are still productive due to intensive management that involves routine treatments with lime and g

Zeppel, M.J., Yunusa, I.A. & Eamus, D. 2006, 'Daily, seasonal and annual patterns of transpiration from a stand of remnant vegetation dominated by a coniferous Callitris species and a broad-leaved Eucalyptus species', Physiologia Plantarum, vol. 127, no. 3, pp. 413-422.
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Quantifying water use of native vegetation is an important contribution to understanding landscape ecohydrology. Few studies provide long-term (more than one growing season) estimates of water use and even fewer quantify interseasonal and interannual var

Chave, J., Andalo, C., Brown, S., Cairns, M.A., Chambers, J.Q., Eamus, D., Folster, H., Fromard, F., Puig, H., Higuchi, N., Nelson, B.W., Kira, T., Lescure, J., Ogawa, H., Yamakura, T. & Riera, B. 2005, 'Tree allometry and improved estimation of carbon stocks and balance in tropical forests', Oecologia, vol. 145, no. 1, pp. 87-99.
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Tropical forests hold large stored of carbonyet uncertainty remains regarding their quantitative contribution to the global carbon cycle. One approach to quantifying carbon biomass stores consists in inferrinng changes from long-term forsts inventory data ito an estimate of aboveground biomass (AGB). We provide a critical reassessment of the quality and the robustness of these models across tropical forest types, using a large dataset of 2,410 trees- 5cm diameter, directly harvested in 27 study sites across the tropics. Proportional relationships between aboveground biomass and the product of wood density, trunk corss-sectional area, and total height are constructed. We also develop aregression model involving wood density and stem diameter only. Our models were tested for secondary and old-growth forets, for dry, moist and wet forests, for lowland and motane forests, and for mangrove forets, Themost important repdicators of AGB of a tree were, in decreasing order of importance, its truck diameter wood specific gravity, total height, and forest type (dry, moist, or wet). Overestimates prevailed, giving a bias of 0.5-6.5% when errors were averaged across all stands. Our regression models can be used reliably to predict aboveground tree biomass across a broad range of tropical forests. Because they are based on an unprecedented dataset, these models should imporve the quality of tropical biomass estimates, and bring consensus about the contribution of the tropical forest biome and tropical deforestation to the global carbon cycle.

Chen, X., Hutley, L.B. & Eamus, D. 2005, 'Soil organic carbon content at a range of north Australian tropical savannas with contrasting site histories', Plant And Soil, vol. 268, no. 1, pp. 161-171.
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Soils play an important role in the global carbon cycle, and can be major source or sink of CO2 depending upon land use, vegetation type and soil management practices. Natural and human impact on soil carbon concentration and storage is poorly understood

Eamus, D., Macinnis-Ng, C.M., Hose, G.C., Zeppel, M.J., Taylor, D.T. & Murray, B.R. 2005, 'Ecosystem services: an ecophysiological examination', Australian Journal Of Botany, vol. 53, no. 1, pp. 1-19.
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This review aims to discuss ecosystem services, provide illustrative case studies at catchment and local scales and present future research needs. This review discusses the following: ( 1) Ecosystem services (ES) are those goods and services that are pro

Lamontagne, S., Cook, P., O'Grady, A.P. & Eamus, D. 2005, 'Groundwater use by vegetation in a tropical savanna riparian zone (Daly River, Australia)', Journal Of Hydrology, vol. 310, no. 1-4, pp. 280-293.
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Soil water matric potentials (Psi(m)) and the deuterium (delta(2)H) composition at natural abundance levels of xylem water, soil water, river water and groundwater were used to evaluate whether trees use groundwater during the dry season in the riparian

Prior, L.D., Bowman, D. & Eamus, D. 2005, 'Intra-specific variation in leaf attributes of four savanna tree species across a rainfall gradient in tropical Australia', Australian Journal Of Botany, vol. 53, no. 4, pp. 323-335.
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Leaf attributes of four savanna tree species were measured along a rainfall gradient (1650-950mm per annum) in the Australian monsoon tropics. As the mean annual rainfall decreased, leaf thickness increased for three of these four species. However, a cor

Yunusa, I.A., Lu, P., Eamus, D. & Walker, R.R. 2005, 'Matching irrigation to vine-water requirements: limitations of using sap-flow technology for scheduling irrigation', Acta Horticulturae, vol. 694, pp. 165-171.
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Mismatch between water applied during irrigation and that required by the crop for transpiration is a major cause of poor returns per unit water use and of land degradation. Advances in commercial sap-flow gauges should provide opportunities for improving water management in tree-horticulture, but this has not been widely explored. In this study we tested the capabilit of sap-flow guages to detect water stress and, hence a need for irrigation, by withholding water for two months from actively growing, mature grapevines. Withholding irrigation reduced soil-water content in the 1.8m soil-profile by almost 40% compared to where irrigation was maintianed, by the reduced soil-water resulted in only a small decrease in the transpirationdeduced from sap flow throughout the 2-month period. This was despite a 3-fold increase in stomatal resistance and a rise of 1.0 C in leaf temperature for the stressed compred to the continuously irrigated vines. Reasons for this response are not clear, but it is possible that the stressed vines accessed water either directly from the waterble or from its capillary fringe. Withdrawal of irrigation also did not result in yield for the stressed-vines. Other implications of these finding are explored including proposals on weighted crop factor to match irrigation with grape-vine water requirements.

Cardoso-Vilhena, J., Balaguer, L., Eamus, D., Ollerenshaw, J. & Barnes, J. 2004, 'Mechanisms underlying the amelioration of O-3-induced damage by elevated atmospheric concentrations of CO2', Journal Of Experimental Botany, vol. 55, pp. 771-781.
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Chen, X., Eamus, D. & Hutley, L.B. 2004, 'Seasonal patterns of fine-root productivity and turnover in a tropical savanna of northern Australia', Journal of Tropical Ecology, vol. 20, pp. 221-224.
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Hose, G.C., Murray, B.R. & Eamus, D. 2004, 'Water quality guidelines to protect groundwater-dependent ecosystems', Ecological Management & Restoration, vol. 5, pp. 78-80.
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Macinnis-Ng, C.M., McClenahan, K. & Eamus, D. 2004, 'Convergence in hydraulic architecture, water relations and primary productivity amongst habitats and across seasons in Sydney', Functional Plant Biology, vol. 31, no. 5, pp. 429-439.
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Convergence in leaf traits across biomes demonstrates generality in plant functioning. Relationships between hydraulic architecture and photosynthesis are less well studied. We investigated convergence in minimum leaf water potential (?min), conductivity per sapwood area (ks), Huber value (Hv) and xylem embolism and photosynthesis of several plant species in four habitats (heathland, woodland (ridge-top), woodland (below ridge) and mangrove) across two seasons (summer and winter) in the Sydney region, New South Wales, Australia. The studied species were: Banksia oblongifolia, Angophora hispida and Persoonia lanceolata (heathland); Eucalyptus haemastoma, Angophora hispida and B. oblongifolia (woodland, ridge-top); B. integrifolia, Cissus hypoglauca and Glochidion ferdinandi (woodland, below ridge); and Avicennia marina and Aegiceras corniculatum (mangrove). Seasonality strongly influenced all parameters in all habitats. Winter ?min values were lower than those for summer in the heathland and both woodland habitats, but summer ?min values were lower than those for winter in the mangrove. Summer ks values were higher than winter values in all habitats, while Hv was higher in winter than summer for all habitats.

McClenahan, K., Macinnis-Ng, C.M. & Eamus, D. 2004, 'Hydraulic architecture and water relations of several species at diverse sites around Sydney', Australian Journal of Botany, vol. 52, pp. 509-518.
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Seasonal comparisons of leaf eater potential, root biomass, hydraulic architecture, xylem embolism and xylem dimensions were made for eight woody species in four diverse habitats (mangroves, coastal heathland, ridge-top woodland and river-flat woodland). In most comparisons, pre-dawn and minimum leaf water potentials were lower in winter than in summer, a result attributed tolower raifall and a smaller root biomass in winter tha in summer. Branch hydraulic conductivities (per unit transverse area, sapwood area or leaf area) were generally larger in summer than in winter across all species in all habutats. An invese relationship between Huber value and conductivity was observed across all four habitats. Increased solar radiation and evaportative deman in the summer was associated with an increased percentage loss of xylem conductance arising from embolism, compared with winter. These results are discussed in the context of patterns and relationships among water relations, microcliate and hydraulic architecture.

McPherson, S., Eamus, D. & Murray, B.R. 2004, 'Seasonal impacts on leaf attributes of several tree species growing in three diverse ecosystems of south-eastern Australia', Australian Journal Of Botany, vol. 52, pp. 293-301.
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Patterns of leaf attributes were examined for six woody species growing in a eucalypt woodland, a mangorve, or a heathland in coastal NSW, Australia, during winter and summer. It was found that the rate of assimilation per unit of dry mass (Amass) of the mangrove species was largest, woodland species exhibiting an intermedaite rate and heathland species the smallest values of Amass. Mean habitat Amass did not change from winter to summer in the woodland or mangrove species but increased significantly in the heathland species. Averag specific leaf area (SLA) was largest for the mangrove species and smallest for the heathland species, with woodland species showing intermediate values. SLA of all species within a habitat did not change from winter to summer.Mean foliar nitrogen content (Nmass of the mangrove species was highest, intermediate for woodland species and lowest for heathland species. NMass was significantly related to Amass in both summer and winter and the individual slopes for this relationship in the summer and winter differed. In contrast, a common slope waws fitted to the relationship between SLA and Amass for the two seasons. A common slope between seasons was also shown for the relationship between SLA and NMass. There was no significant diffeence in slope elevation between summer and winter for the SLA v. Nmass relationship. Trends within relationships among leaf attributes were the same as those found for a wide range of plant species worldwide, but the absolute values were loer than those foudn elsewhere. Therefore the global relationships in terms of trends (positive or negative) that have been determined overseas apply in Australia but the elevation of th sloep and the magnitidue of the slope are reduced (Amass v. Nmass) or increased (Amass v. SLA and Nmass v. SLA) compared with global trends.

Prior, L.D., Bowman, D. & Eamus, D. 2004, 'Seasonal differences in leaf attributes in Australian tropical tree species: family and habitat comparisons', Functional Ecology, vol. 18, pp. 707-718.
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Prior, L.D., Eamus, D. & Bowman, D. 2004, 'Tree growth rates in north Australian savanna habitats: seasonal patterns and correlations with leaf attributes', Australian Journal Of Botany, vol. 52, pp. 303-314.
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We demonstate a significant relationship between leaf attributes and growth rates of mature trees under natural conditions in northern Australia, a pattern that has not been widely reported before in the literature. Increase in diameter at breast height (DBH) was measured every 3 months for 2 years for 21 tree species from four habitats near Darwin: Eucalyotus open forest, mixed woodland, Melaleuca swamp and dry monsoon rainforest. Assimilation rates and foliar chlorophyll, nitrogen and phosphorus concentrations were positively correlated with growth rate and negatively correlated with leaf mass per area. For most species, increases inDBH were confined to the wet-season (summer) period between November and May. Average annual increases in DBH were larger in the dry monsoon rainforest (0.87 cm) and the Melaleuca swamp (0.65 cm) than in Myrtaceous species (0.25 cm). These results are discussed in relation to the frequent fire regime prevailing over much of northern Australia which causes the marked contrast between the small pockets of fire-tender closed monsoon rainforest and the surrounding large expanses of fr=ire-tolerant savanna.

Zeppel, M.J., Murray, B.R., Barton, C. & Eamus, D. 2004, 'Seasonal responses of xylem sap velocity to VPD and solar radiation during drought in a stand of native trees in temperate Australia', Functional Plant Biology, vol. 31, pp. 461-470.
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Xylem sap velocity of two dominant tree species, Eucalyptus crebra F. Muell and Callitris glaucophylla J. Thopson & LAS Johnson, in a native remnant forest of eastern Australia was measured in winter and summer during a rpolonged (> 12 months) and extensive drought. The influence of vapour pressure deficit (VPD) and solar radiation levels onthe velocity of sap was determined. Pronounced hysteresis in sap velocity was observed in both species as a function of VPD and solar radiation. However the rotation of the hysteresis curve was clockwise for the response of sap velocity to VPD but anti-clockwise in the response of sap bvelocity to radiation levels. A possible reason for this difference is discussed. The degree of hysteresis (area bounded by the curve) was larger for the VPD response than the response to solar radiation and also varied with season. A simple linear model was able to predict sap velocity from knowledge of VPD and solar radiation in winter and summer. The consistent presence of hysteresis in the response to sap velocity to VPD and solar radiation suggests that large temporal and spatial models of vegetation water use may require soem provision for the different responses of sap velocity, and hence water use, to VPD and solar radiation, between morninga nd afternoon and between seasons.

Chen, X., Hutley, L.B. & Eamus, D. 2003, 'Carbon balance of tropical savanna of northern Australia', Oecologia, vol. 137, pp. 405-416.
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Choinski, J.S., Ralph, P.J. & Eamus, D. 2003, 'Changes in photosynthesis during leaf expansion in Corymbia gummifera', Australian Journal Of Botany, vol. 51, no. 1, pp. 111-118.
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Eamus, D. 2003, 'How does ecosystem water balance affect net primary productivity of woody ecosystems?', Functional Plant Biology, vol. 30, no. 2, pp. 187-205.
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Murray, B.R., Zeppel, M.J., Hose, G.C. & Eamus, D. 2003, 'Groundwater-dependent ecosystems in Australia: it's more than just water for rivers', Ecological Management & Restoration, vol. 4, no. 2, pp. 110-113.
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Prior, L.D., Eamus, D. & Bowman, D. 2003, 'Leaf attributes in the seasonally dry tropics: a comparison of four habitats in northern Australia', Functional Ecology, vol. 17, no. 4, pp. 504-515.
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Zeppel, M.J., Murray, B.R. & Eamus, D. 2003, 'The potential impact of dryland salinity on the threatened flora and fauna of New South Wales', Ecological Management & Restoration, vol. 4 (Sup.), pp. 53-59.
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Chen, X., Eamus, D. & Hutley, L.B. 2002, 'Seasonal pattens of soil carbon dioxide efflux from a wet-dry tropical savanna of northern Australia', Australian Journal of Botany, vol. 50, no. N/A, pp. 43-51.
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Eamus, D. & Shanahan, S. 2002, 'A rate equation model of stomatal responses to vapour pressure deficit and drought', BMC Ecology, vol. 2, no. N/A N/A.
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Stomata respond to vapour pressure deficit (D) + when D increases, stomata begin to close. Closure is the result of a decline in guard cell turgor, but the link between D and turgor is poorly understood. We describe a model for stomatal responses to increasing D based upon cellular water relations. The model also incorporates impacts of increasing levels of water stress upon stomatal responses to increasing D.

Eamus, D., Chen, X., Kelly, G. & Hutley, L.B. 2002, 'Root biomass and root fractal analyses of an open Eucalyptus forest in a savanna of north Australia', Australian Journal of Botany, vol. 50, no. N/A, pp. 31-41.
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Thomas, D.D. & Eamus, D. 2002, 'Seasonal patterns of xylem sap pH, cylem abscisic acid concentration, leaf water potential and stomatal conductance of six evergreen and deciduous Australian savanna tree species', Australian Journal of Botany, vol. 50, no. N/A, pp. 229-236.
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Eamus, D., Hutley, L.B. & O'Grady, A.P. 2001, 'Daily and Seasonal Patterns of Carbon and Water Fluxes Above a North Australian Savanna', Tree Physiology, vol. 21, pp. 977-988.
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Daily and seasonal fluxes of carbon dioxide and water vapor above a north Australian savanna were recorded over a complete dry season wet season annual cycle using the eddy covariance technique. Wet season rates of photosynthesis and transpiration were larger than those measured in the dry season and were dominated by the presence of the grassy understory. As the dry season progressed and the grass understory died, ecosystem rates of assimilation and water vapor flux declined substantially. By the end of the dry season, canopy assimilation and evapotranspiration rates were 20 25% of wet season values. Assimilation was light saturated in the dry season but not in the wet season. Stomatal control of transpiration increased between the wet and dry season. This was revealed by the decline in the slope of E with increasing leaf-to-air vapor pressure difference (D) between wet and dry seasons, and also by the significant decrease in the ratio of boundary to canopy conductance observed between the wet and dry seasons. A simple pan-tropical modeling of leaf area index or wet season canopy CO2 flux was undertaken. It was shown that with readily available data for foliar N content and the ratio of rainfall to potential evaporation, leaf index and wet season canopy CO2 flux can be successfully estimated for a number of tropical ecosystems, including north Australian savannas.

Eamus, D. & Prior, L.D. 2001, 'Ecophysiology of Trees of Seasonally Dry Tropics: Comparisons Among Phenologies', Advances in Ecological Research, vol. 32, pp. 113-197.
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Hutley, L.B., O'Grady, A.P. & Eamus, D. 2001, 'Monsoonal Influences on Evapotranspiration of Savanna Vegetation of Northern Australia', Oecologia, vol. 126, pp. 434-443.
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Eamus, D., O'Grady, A.P. & Hutley, L.B. 2000, 'Dry Season Conditions Determine Wet Season Water Use In The Wet-Dry Tropical Savannas Of Northern Australia', Tree Physiology, vol. 20, no. 18, pp. 1219-1226.
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Daily and seasonal patterns of transpiration were measured in evergreen eucalypt trees growing at a wet (Darwin), intermediate (Katherine) and dry site (Newcastle Waters) along a steep rainfall gradient in a north Australian savanna. Relationships betwee

Fordyce, I., Eamus, D. & Duff, G. 2000, 'Episodic Seedling Growth In Allosyncarpia Ternata, A Lignotuberous, Monsoon Rainforest Tree In Northern Australia', Austral Ecology, vol. 25, no. 1, pp. 25-35.
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On the western Arnhem Land Plateau, Northern Territory, Australia, seedlings of the canopy tree Allosyncarpia ternata S.T. Blake typically spend many years (perhaps decades) as small (< 1 m), multistemmed plants on the forest floor. In this establishment

O'Grady, A.P., Chen, X., Eamus, D. & Hutley, L.B. 2000, 'Composition, Leaf Area Index And Standing Biomass Of Eucalypt Open Forests Near Darwin In The Northern Territory, Australia', Australian Journal Of Botany, vol. 48, no. 5, pp. 629-638.
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Savanna communities dominate the wet dry tropical regions of the world and are an important community type in monsoonal northern Australia. As such they have a significant impact on the water and carbon balance of this region. Above the 1200-mm isohyet,

Hutley, L.B., O'Grady, A.P. & Eamus, D. 2000, 'Evapotranspiration From Eucalypt Open-Forest Savanna Of Northern Australia', Functional Ecology, vol. 14, no. 2, pp. 183-194.
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1. Using three independent methods (eddy covariance, heat pulse and open-top chambers), diurnal and seasonal measurements of evapotranspiration were made in a wet-dry Eucalypt savanna of the Northern Territory, Australia. 2. Total annual dry-canopy water

Prior, L.D. & Eamus, D. 2000, 'Seasonal Changes In Hydraulic Conductance, Xylem Embolism And Leaf Area In Eucalyptus Tetrodonta And Eucalyptus Miniata Saplings In A North Australian Savanna', Plant Cell And Environment, vol. 23, no. 9, pp. 955-965.
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Eucalypt saplings in north Australian savannas commonly die back, sometimes to ground level, during the 5 months of the long dry season, Wafer potentials are lower in saplings than large trees during the dry season, and we hypothesized that low water pot

Thomas, D.W., Eamus, D. & Shanahan, S. 2000, 'Influence Of Season, Drought And Xylem Aba On Stomatal Responses To Leaf-To-Air Vapour Pressure Difference Of Trees Of The Australian Wet-Dry Tropics', Australian Journal Of Botany, vol. 48, no. 2, pp. 143-151.
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This paper reports the results of two experiments undertaken to investigate the influence of season and soil drying on stomatal responses to leaf-to-air vapour pressure differences. We examined the response of stomatal conductance to increasing leaf-to-a

Eamus, D., Myers, B., Duff, G. & Williams, R.P. 1999, 'A Cost-Benefit Analysis Of Leaves Of Eight Australian Savanna Tree Species Of Differing Leaf Life-Span', Photosynthetica, vol. 36, no. 4, pp. 575-586.
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Cost-benefit analyses of foliar construction and maintenance costs and of carbon assimilation of leaves of differing life-span were conducted using two evergreen, three semi-deciduous, and three deciduous tree species of savannas of north Australia. Rate

Eamus, D. 1999, 'Ecophysiological Traits Of Deciduous And Evergreen Woody Species In The Seasonally Dry Tropics', Trends In Ecology & Evolution, vol. 14, no. 1, pp. 11-16.
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Seasonally dry tropical ecosystems occur in the Americas, Africa, India and Australia. They sustain large human populations, determine regional climate, are sites of biological and cultural conservation, and have significant economic value. Evergreen, de

Eamus, D., Myers, B., Duff, G. & Williams, D.J. 1999, 'Seasonal Changes In Photosynthesis Of Eight Savanna Tree Species', Tree Physiology, vol. 19, no. 10, pp. 665-671.
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Seasonal variations in carbon assimilation of eight tree species of a north Australian tropical savanna were examined over two wet seasons and one dry season (18 months). Assimilation rates (A) in the two evergreen species, Eucalyptus tetrodonta F Muell.

O'Grady, A.P., Eamus, D. & Hutley, L.B. 1999, 'Transpiration Increases During The Dry Season: Patterns Of Tree Water Use In Eucalypt Open-Forests Of Northern Australia', Tree Physiology, vol. 19, no. 9, pp. 591-597.
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Australian savannas exhibit marked seasonality in precipitation, with more than 90% of the annual total falling between October and May. The dry season is characterized by declining soil water availability and high vapor pressure deficits (up to 2.5 kPa)

Prior, L.D. & Eamus, D. 1999, 'Seasonal Changes In Leaf Water Characteristics Of Eucalyptus Tetrodonta And Terminalia Ferdinandiana Saplings In A Northern Australian Savanna', Australian Journal Of Botany, vol. 47, no. 4, pp. 587-599.
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The monsoonal areas of northern Australia experience extreme seasonal variations in rainfall, with an annual dry season of 7 months or more. Seasonal changes in leaf water relations were investigated for saplings of two tree species common in northern Au

Thomas, D.W., Eamus, D. & Bell, D.R. 1999, 'Optimization Theory Of Stomatal Behaviour - I. A Critical Evaluation Of Five Methods Of Calculation', Journal Of Experimental Botany, vol. 50, no. 3, pp. 385-392.
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There are two principal aims in this first manuscript, first, to compare five methods for calculating the marginal unit water cost of plant carbon gain (partial derivative E/partial derivative A) of leaves of two Australian tropical tree species, and sec

Thomas, D.W., Eamus, D. & Bell, D.R. 1999, 'Optimization Theory Of Stomatal Behaviour - Ii. Stomatal Responses Of Several Tree Species Of North Australia To Changes In Light, Soil And Atmospheric Water Content And Temperature', Journal Of Experimental Botany, vol. 50, no. 3, pp. 393-400.
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In a companion paper several methods of calculating the marginal unit water cost of plant carbon gain (partial derivative E/partial derivative A) were tested to determine whether stomata were behaving optimally in relation to regulating leaf gas exchange

Thomas, D.W. & Eamus, D. 1999, 'The Influence Of Predawn Leaf Water Potential On Stomatal Responses To Atmospheric Water Content At Constant C-I And On Stem Hydraulic Conductance And Foliar Aba Concentrations', Journal Of Experimental Botany, vol. 50, no. 2, pp. 243-251.
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Stomatal and photosynthetic responses to increasing leaf-to-air vapour pressure difference (V) were investigated in watered and droughted Eucalyptus tetrodonta when either ambient CO2 (C-a) or internal CO2 concentration (C-i) were constant, Stem hydrauli

Cook, P., Hatton, T., Pidsley, D., Herczeg, A., Held, A., O'Grady, A.P. & Eamus, D. 1998, 'Water Balance Of A Tropical Woodland Ecosystem, Northern Australia: A Combination Of Micro-Meteorological, Soil Physical And Groundwater Chemical Approaches', Journal Of Hydrology, vol. 210, no. 1-4, pp. 161-177.
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A combination of micro-meteorological, soil physical and groundwater chemical methods enabled the water balance of a tropical eucalypt savanna ecosystem in Northern Australia to be estimated. Heat pulse and eddy correlation were used to determine oversto

Eamus, D. & Prichard, H. 1998, 'A Cost-Benefit Analysis Of Leaves Of Four Australian Savanna Species', Tree Physiology, vol. 18, no. 8-Sep, pp. 537-545.
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We conducted a cost-benefit analysis of the contrasting phenologies of two evergreen and two deciduous species of the savannas of north Australia. Stomatal conductance, rates of light-saturated assimilation (A(max)) and dark respiration were measured for

Thomas, D.W., Turner, D.W. & Eamus, D. 1998, 'Independent Effects Of The Environment On The Leaf Gas Exchange Of Three Banana (Musa Sp.) Cultivars Of Different Genomic Constitution', Scientia Horticulturae, vol. 75, no. 1-2, pp. 41-57.
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Circumstantial evidence suggests that the Musa balbisiana (B) genome confers greater drought tolerance to bananas and plantains than the Musa acuminata (A) genome. Hence the genetic makeup of bananas and plantains may affect the response of leaf gas exch

Duff, G., Myers, B., Williams, R.P., Eamus, D., O'Grady, A.P. & Fordyce, I. 1997, 'Seasonal Patterns In Soil Moisture, Vapour Pressure Deficit, Tree Canopy Cover And Pre-Dawn Water Potential In A Northern Australian Savanna', Australian Journal Of Botany, vol. 45, no. 2, pp. 211-224.
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The wet-dry tropics of northern Australia are characterised by extreme seasonal variation in rainfall and atmospheric vapour:pressure deficit, although temperatures are relatively constant throughout the year. This seasonal variation is associated with m

Eamus, D. & Cole, S. 1997, 'Diurnal And Seasonal Comparisons Of Assimilation, Phyllode Conductance And Water Potential, Of Three Acacia And One Eucalyptus Species In The Wet-Dry Tropics Of Australia', Australian Journal Of Botany, vol. 45, no. 2, pp. 275-290.
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Four species of tropical tree (Acacia auriculiformis Cunn. ex Benth., A. mangium Willd., A. crassicarpa Cunn. ex Benth. and Eucalyptus pellita F.Muell.) were studied at a site on Melville Island, off the north coast of the Northern Territory of Australia

Fordyce, I., Duff, G. & Eamus, D. 1997, 'The Water Relations Of Allosyncarpia Ternata (Myrtaceae) At Contrasting Sites In The Monsoonal Tropics Of Northern Australia', Australian Journal Of Botany, vol. 45, no. 2, pp. 259-274.
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Allosyncarpia ternata S.T.Blake (Myrtaceae) is an evergreen tree, restricted largely to rocky habitats on the Arnhem Land Plateau in the wet-dry tropics of northern Australia. Allosyncarpia ternata grows in a wide range of habitats, including sites near

Goodfellow, J., Eamus, D. & Duff, G. 1997, 'Diurnal And Seasonal Changes In The Impact Of CO2 Enrichment On Assimilation, Stomatal Conductance And Growth In A Long-Term Study Of Mangifera Indica In The Wet-Dry Tropics Of Australia', Tree Physiology, vol. 17, no. 5, pp. 291-299.
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We studied assimilation, stomatal conductance and growth of Mangifera indica L. saplings during long-term exposure to a CO2-enriched atmosphere in the seasonally wet-dry tropics of northern Australia. Grafted saplings of M. indica were planted in the gro

Myers, B., Duff, G., Eamus, D., Fordyce, I., O'Grady, A.P. & Williams, R.P. 1997, 'Seasonal Variation In Water Relations Of Trees Of Differing Leaf Phenology In A Wet-Dry Tropical Savanna Near Darwin, Northern Australia', Australian Journal Of Botany, vol. 45, no. 2, pp. 225-240.
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The seasonal variation in leaf xylem pressure potential at dawn (psi(dawn)), leaf tissue water characteristics and daily maximum leaf conductance was measured in eight woody species in a wet-dry tropical savanna near Darwin, northern Australia, between O

Prior, L.D., Eamus, D. & Duff, G. 1997, 'Seasonal and Diurnal Patterns of Carbon Assimilation, Stomatal Conductance and Leaf Water Potential in Eucalyptus tetrodonta Saplings in a Wet+Dry Savanna in Northern Australia', Australian Journal Of Botany, vol. 45, no. 2, pp. 241-258.
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Seasonal and diurnal trends in carbon assimilation, stomatal conductance and leaf water potential were studied using 1-3 m tall saplings of Eucalyptus tetrodonta (F.Muell.). The study site was in an unburnt savanna near Darwin, where rainfall is strongly

Prior, L.D., Eamus, D. & Duff, G. 1997, 'Seasonal Trends In Carbon Assimilation, Stomatal Conductance, Pre-Dawn Leaf Water Potential And Growth In Terminalia Ferdinandiana, A Deciduous Tree Of Northern Australian Savannas', Australian Journal Of Botany, vol. 45, no. 1, pp. 53-69.
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Seasonal trends in pre-dawn leaf water potential and morning and afternoon rates of light-saturated assimilation and stomatal conductance were studied in saplings of the deciduous tree Terminalia ferdinandiana Excell. Mean daily maximum assimilation rate

Williams, R.P., Myers, B., Muller, W.J., Duff, G. & Eamus, D. 1997, 'Leaf Phenology Of Woody Species In A North Australian Tropical Savanna', Ecology, vol. 78, no. 8, pp. 2542-2558.
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Leaf phenology was monitored for 49 woody species (trees and tall shrubs) each month over a 2.5-year period in a humid, wet-dry tropical eucalypt savanna at Solar Village, near Darwin, Australia. In the 10 most common species, which spanned the range of

Eamus, D. 1996, 'Tree Responses To Co2 Enrichment: Co2 And Temperature Interactions, Biomass Allocation And Stand-Scale Modeling', Tree Physiology, vol. 16, no. 1-2, pp. 43-47.
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In this review, I focus on modeling studies of tree responses to CO2 enrichment. First, I examine leaf-scale models of assimilation with respect to the interaction between low temperature and CO2 enrichment. Second, because changes in allocation within a

Landrigan, M., Morris, S.C., Eamus, D. & McGlasson, W.B. 1996, 'Postharvest Water Relationships And Tissue Browning Of Rambutan Fruit', Scientia Horticulturae, vol. 66, no. 3-Apr, pp. 201-208.
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The water status of excised spinterns or spintern plus pericarp and attached endocarp of rambutan fruits was measured three times during storage at 20 degrees C, Changes in fruit colour were also recorded. The development of browning was preceded by wate

Eamus, D., Duff, G. & Berryman, C. 1995, 'Photosynthetic Responses To Temperature, Light Flux-Density, Co2 Concentration And Vapor-Pressure Deficit In Eucalyptus Tetrodonta Crown Under Co2 Enrichment', Environmental Pollution, vol. 90, no. 1, pp. 41-49.
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Seeds of Eucalyptus tetrodonta were sown under ambient or CO2 enriched (700 mu l litre(-1)) conditions in tropical Australia. Four sets of measurements were made, the first two after 12 months, on trees growing either in pots or planted in the ground. Th

Eamus, D., Berryman, C. & Duff, G. 1995, 'The Impact Of Co2 Enrichment On Water Relations In Maranthes-Corymbosa And Eucalyptus-Tetrodonta', Australian Journal Of Botany, vol. 43, no. 3, pp. 273-282.
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Seeds of Maranthes corymbosa Blume and Eucalyptus tetrodonta F.Muell were sown under ambient or CO2 enriched conditions (two replicate tents per treatment) in tropical Australia and allowed to grow, rooted in the ground, for 20 months. For both species,

Fordyce, I., Duff, G. & Eamus, D. 1995, 'The Ecophysiology Of Allosyncarpia-Ternata (Myrtaceae) In Northern Australia - Tree Physiognomy, Leaf Characteristics And Assimilation At Contrasting Sites', Australian Journal Of Botany, vol. 43, no. 4, pp. 367-377.
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Allosyncarpia ternata S.T.Blake, a large, evergreen tree endemic to the northern part of the Northern Territory, Australia, dominates the canopy in a wide variety of habitats, including monsoon rainforest on ravine floors, open forest and woodland on cli

Cole, S., Woo, K., Eamus, D., Harwood, C. & Haines, M. 1994, 'Field-Measurements Of Net Photosynthesis And Related Parameters In 4 Provenances Of Acacia-Auriculiformis', Australian Journal Of Botany, vol. 42, no. 4, pp. 457-470.
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Tree diameter at breast height (DBH), tree height, maximum light saturated assimilation (A(max)), phyllode conductance (g(s)), and phyllode water potential (psi(W)) were determined in trees of Acacia auriculiformis A. Cunn. ex Benth., 3-4 years old. Tree

Berryman, C., Eamus, D. & Duff, G. 1993, 'The Influence Of CO2 Enrichment On Growth, Nutrient Content And Biomass Allocation Of Maranthes-Corymbosa', Australian Journal Of Botany, vol. 41, no. 2, pp. 195-209.
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Seedlings of Maranthes corymbosa Blume, an evergreen tree of tropical Australia and Indonesia were grown for 32 weeks under conditions of ambient and elevated (700 mumol CO2 mol-1) CO2 in tropical northern Australia. Seedlings were exposed to ambient tem

Eamus, D. 1993, 'Assimilation And Stomatal Conductance Responses Of Red Spruce To Midwinter Frosts And The Constituent Ions Of Acid Mist', Tree Physiology, vol. 13, no. 2, pp. 145-155.
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Red spruce (Picea rubens Sarg.) seedlings growing outside in open-top chambers were sprayed twice weekly with artificial mists at either pH 2.5 or 5.6, for five months during the 1988 growing season. The mists contained one of the following: (water, pH 5

Eamus, D. & Murray, M. 1993, 'The Impact Of Constituent Ions Of Acid Mist On Assimilation And Stomatal Conductance Of Norway Spruce Prior And Post Midwinter Freezing', Environmental Pollution, vol. 79, no. 2, pp. 135-142.
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Norway spruce seedlings were sprayed twice weekly with one of a range of artificial mists at either pH 2.5, 3.0 or 5.6, for three months. The mists consisted of either (NH4)2SO4 (pH 5-6), NH4NO3 (pH 5-6), water (pH 5-6), HNO3 (Ph 2.5), HSO4 (pH 2-5 or pH

Wiebel, J., Eamus, D., Chacko, E.K., Downton, W. & Ludders, P. 1993, 'Gas-Exchange Characteristics Of Mangosteen (Garcinia-Mangostana L) Leaves', Tree Physiology, vol. 13, no. 1, pp. 55-69.
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Gas exchange responses of mangosteen (Garcinia mangostana L.) leaves to photosynthetic photon flux density (PPFD), internal CO2 concentration (C(i)), leaf-air vapor pressure deficit (VPD), leaf temperature (T(l)) and time of day were investigated in plan

Berryman, C., Eamus, D. & Farrar, J. 1991, 'The Hydraulic Conductivity Of Roots Of Rust-Infected Barley Seedlings', Physiological And Molecular Plant Pathology, vol. 38, no. 6, pp. 407-415.
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The influence of Puccinia hordei (rust) infection on the root hydraulic conductivity (Lp) of excised roots of Hordeum distichum cv. Maris Mink (barley) was investigated using the Scholander pressure chamber technique. The solute potential of the root exudate was also measured to determine the contribution of the osmotic component to the total driving force for water flow across the roots. The root Lp of infected plants was significantly lower than control plants on days 5, 6 and 7 after infection. On days 4 and 8 after infection, Lp did not differ significantly. Root Lp increased with time for both control and infected plants from days 5 to 8 after infection. Root Lp varied between 1À4 and 3À6 Î 10-5 cm s-1 MPa-1 for roots of infected plants, and between 2À3 and 4À0 Î 10-5 cm s-1 MPa-1 for control plants. The solute potential of root xylem sap exudate was significantly higher (less negative) than that of control sap on days 6, 7 and 8 after infection, reflecting a decrease in the transport of solutes into the root xylem of roots of diseased plants. In control and infected plants, as the applied pressure increased, solute potential root exudate increased. These results are discussed in relation to the known susceptibility of rust infected plants to drought and the mechanisms by which rust infection increases such susceptibility

Berryman, C., Eamus, D. & Farrar, J. 1991, 'Variations In Epidermal-Cell Turgor Of Rust-Infected Barley Seedlings', New Phytologist, vol. 119, no. 4, pp. 535-540.
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Barley [Hordeum distichum (L.) Lam.] seedlings were infected with urediniospores of rust, Puccinia hordei Otth., 10 d after germination and the Zimmermann micro-pressure probe was used to measure the turgor potential of individual epidermal and palisade

Berryman, C., Eamus, D. & Farrar, J. 1991, 'Water Relations Of Leaves Of Barley Infected With Brown Rust', Physiological And Molecular Plant Pathology, vol. 38, no. 6, pp. 393-405.
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The water balance of brown rust (Puccinia hordei) infected barley seedlings was investigated. It was found that with the progression of the disease, the infected leaves lost their ability to maintain a favourable water status. This was attributed to tears in the cuticle, which occurred from day 5 after infection. In addition, a decreasing responsiveness of leaf diffusion resistance to bulk leaf water content was observed, probably due to the increasing proportion of water loss via the tears in the cuticle. An increase in leaf dry weight per unit area which was not associated with an increase in tissue volume, was found in diseased leaves. These responses to infection were cumulative with disease development, with no sudden effect of sporulation. Leaf turgor and water potentials were found to be lower in diseased leaves than in control leaves.

Cape, J., Leith, I., Fowler, D., Murray, M., Sheppard, L., Eamus, D. & Wilson, R. 1991, 'Sulfate And Ammonium In Mist Impair The Frost Hardening Of Red Spruce Seedlings', New Phytologist, vol. 118, no. 1, pp. 119-126.
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Two-year-old seedlings of red spruce [Picea rubens Sarg. syn. P. rubra (Du Roi) Link] were grown in open-top chambers supplied with charcoal-filtered air near Edinburgh, Scotland. Between May and November 1988, plants were exposed to mists containing NH

Eamus, D. & Murray, M. 1991, 'Photosynthetic And Stomatal Conductance Responses Of Norway Spruce And Beech To Ozone, Acid Mist And Frost - A Conceptual-Model', Environmental Pollution, vol. 72, no. 1, pp. 23-44.
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Two-year-old beech and Norway spruce seedlings were exposed to a combination of ozone and acid mist treatments in open-top chambers in Scotland during the months of July through to September 1988. Replicate pairs of chambers received charcoal-filtered a

Barnes, J., Eamus, D., Davison, A.W., Ropoulsen, H. & Mortensen, L. 1990, 'Persistent Effects Of Ozone On Needle Water-Loss And Wettability In Norway Spruce', Environmental Pollution, vol. 63, no. 4, pp. 345-363.
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Four-year-old, seed-grown trees of Norway spruce (Picea abies (L.) Karst.) were exposed in open-top chambers to charcoal-filtered air (8 h daily mean 54 ?g O3 m-3) over three consecutive summers (1986+1988). In mid-May 1988, before the third season of fumigation and more than 7 months after exposure to ozone the previous summer had terminated, daily rates of transpiration from intact shoots and water loss from excised needles were measured together with the amount of wax on the needle surface. In mid-July, 92 days after the beginning of the third year of exposure, the wettability of needles was assessed by measuring the contact angle of water droplets on the surface of needles. Exposure to 156 ?g O3 m-3 resulted in a 16% increase in daily transpiration in current year's needles and a 28% increase in 1-year old needles. These effects were associated with slower stomatal closure in response to increasing water deficit in the needles previously exposed to 156 ?g m-3 ozone. The long-lasting nature of such ozone-induced effects could predispose trees to drought and winter desiccation. No significant effects of ozone were found on the amount of wax covering the needle surface, but a marked increase in the wettability of needles exposed to ozone was observed. The far reaching physiological consequences of these effects in the field and the possibility that similar disturbances may contribute to the decline of high-altitude forests of Norway spruce in Europe are discussed.

Barnes, J., Eamus, D. & Brown, K.R. 1990, 'The Influence Of Ozone, Acid Mist And Soil Nutrient Status On Norway Spruce [Picea-Abies (L) Karst]', New Phytologist, vol. 114, no. 4, pp. 713-720.
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Three-year old Norway spruce [Picea abies (L.) Karst.] trees established from two clones (4076 and 2470) of a medium-altitude southern German provenance, were transplanted in May 1986 into two acid brown earth soils which differed particularly in the amounts of exchangeable Ca2+and Mg2+. During the summers of 1987 and 1988 trees were exposed in large-scale fumigation chambers (solardomes) to ozone at 200 or 40 Ág-3(control). Each day trees were treated with acid (pH 3-6) or control (pH 5-5) mist solution. In late autumn 1988 certain aspects of tree water relations were investigated. In clone 4076 ozone and acid mist reduced stomatal conductance in the light, but resulted in incomplete stomatal closure at night, reducing the diel range of stomatal conductance in treated trees grown on both soils. In addition, current year's needles excised from clone 4076 dried more rapidly following exposure to ozone and/or acid mist than needles from control trees, indicating impaired stomatal performance. However, evidence of both clonai and soil variation in this response was found. Cellular water relations of current year's shoots of clone 4076 were investigated using pressure-volume analysis. Exposure to ozone and/or acid mist resulted in a marked increase in the plasticity of tissues (reduction in ?) compared with controls, indicating that the pollutants induced cell wall loosening. In trees exposed to acid mist this was associated with lower cellular solute concentrations and a decrease in maximum turgor.

Barnes, J., Eamus, D. & Brown, K.R. 1990, 'The Influence Of Ozone, Acid Mist And Soil Nutrient Status On Norway Spruce [Picea-Abies (L) Karst] .2. Photosynthesis, Dark Respiration And Soluble Carbohydrates Of Trees During Late Autumn', New Phytologist, vol. 115, no. 1, pp. 149-156.
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Three-year old Norway spruce [Picea abies (L.) Karst.] trees of clonal stock originating from medium altitude in southern Germany were transplanted in May 1986 into two acid brown-earth soils which differed particularly in the amounts of exchangeable Ca2+ and Mg2+. During the summers of 1987 and 1988 trees were exposed in large-scale fumigation chambers (solardomes) to ozone at 200 or 40 (control) Ág m-3 Acid (pH 3?6) or control mist (pH 5?5) solution was applied daily to trees in each half of the solardomes. In late autumn (1988) the light response of CO2 exchange, and the chlorophyll and soluble carbohydrate contents of needles were determined. Ozone and/or acid mist treatment had only minor (< 10%) effects on the light-saturated rate of photosynthesis which were not statistically significant in plants from either soil. Needles from trees raised on the richer soil and exposed to a combination of ozone and acid mist showed a significant increase in the apparent quantum yield of photosynthesis which was associated with an increase in chlorophyll content. Ozone (alone) stimulated the rate of dark respiration by 40 and 58 % for trees grown in richer and poorer soils, respectively, and this was associated with a decrease in ethanol-soluble carbohydrate content of needles. Where significant interactions between ozone and acid mist were found, they were generally antagonistic. The reduction in the ethanol-soluble carbohydrates would be expected to reduce frost hardiness, and may contribute to the increased sensitivity of ozone-treated needles to freezing, which has been reported in previous studies.

Eamus, D. & Narayan, A. 1990, 'A pressure-volume analysis of Solanum-Melongena Leaves', Journal Of Experimental Botany, vol. 41, no. 6, pp. 661-668.
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A pressure-volume analysis of aubergine (Solanum melongena) leaves following water stress was undertaken to determine a possible role of changes in cellular water relations in influencing stomatal conductance responses to water stress. A comparison of two methods of rehydrating the leaves was also undertaken. It was shown that the rehydration of excised leaves did not reveal osmoregulation, whilst rehydration of intact plants did reveal osmoregulation following water stress. An increase in the bulk volumetric elastic modulus and the bound water fraction also occurred in response to water stress. These results are discussed in relation to pressure-volume technique and stomatal conductance responses to drought

Eamus, D., Barnes, J., Mortensen, L., Ropoulsen, H. & Davison, A.W. 1990, 'Persistent Stimulation Of Co2 Assimilation And Stomatal Conductance By Summer Ozone Fumigation In Norway Spruce', Environmental Pollution, vol. 63, no. 4, pp. 365-379.
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CO2 assimilation rate, stomatal conductance and chlorophyll content of current and previous years' needles of Norway spruce were measured in May 1988, 205 days after the cessation of ozone fumigation during the summer of 1987. Rates of assimilation were consistently higher for both needle year age classes for ozone fumigated trees in comparison to control trees, although only statistically significant for part of the day for current year's needles. A 26% and 48% stimulation, overall, in mean daily rates of assimilation for current and previous years' needles of ozone fumigated trees was observed. This was due to an enhanced apparent quantum yield and light saturated rate of assimilation of ozone fumigated trees. The temperature response regression of assimilation versus temperature was also greater, such that at any given temperature, assimilation was higher for ozone treated trees than control trees. Stomatal conductance was greater for ozone fumigated trees than the controls, but this was only marginally statistically significant. Moreover, there was a consistent increase in chlorophyll content in both year classes in ozone-treated trees. These results are discussed in relation to a possible long term effect of ozone fumigation upon the processes of conifer winter hardening and spring de-hardening.

Eamus, D., Barnes, J., Mortensen, L., Ropoulsen, H. & Davison, A.W. 1989, 'A Delayed-Effect Of Ozone Fumigation On Photosynthesis Of Norway Spruce', Annales Des Sciences Forestieres, vol. 46, pp. 568-572.
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Much of the research investigating the effects of gaseous pollutants upon plants has been concerned with dose-response relationships, particularly during the period of fumigation or in between the periods of fumigation, in the summer. However, there is increasing evidence that these pollutants increase plant susceptibility to winter injury (Barnes and Davison, 1988; Brown ef al., 1987). This is especially problematic for conifers, since they maintain needles and some metabolic activity throughout the winter. Indeed, there is increasing evidence that the forest decline documented for northeastern U.S.A. and Europe results from the interaction of various abiotic and biotic factors including air pollutants, frost and winter dessication (Brown et aL, 1987; Barnes and Davison, 1988).

Eamus, D., Leith, I. & Fowler, D. 1989, 'Water Relations Of Red Spruce Seedlings Treated With Acid Mist', Tree Physiology, vol. 5, no. 3, pp. 387-397.
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Pressure+volume curves, day and night transpiration rates, needle drying curves, and shoot water potentials were determined for 2-year-old red spruce trees that had been exposed for three months to a range of acid mists (pH 2.5 to pH 5.0) containing equimolar (NH4)2SO4 and HNO3. No effect of acid mist was observed on cuticular resistance or on the rates of day and night transpiration, although trees exposed to acid mist exhibited symptoms of mild water stress. Significant decreases in maximum turgor, the relative water content (RWC) associated with zero turgor, and bulk volumetric elastic modulus occurred as the pH of the mist decreased from 5.0 to 2.5. At all RWC values, there was an increase in solute potential as mist pH decreased. Shoot water potential declined with a decrease in pH of the mist.

Eamus, D. & Jennings, D. 1986, 'Turgor And Fungal Growth - Studies On Water Relations Of Mycelia Of Serpula-Lacrimans And Phallus-Impudicus', Transactions Of The British Mycological Society, vol. 86, pp. 527-535.
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The influence of substratum water potential on the growth of Serpula lacrimans and Phallus impudicus was investigated. Two methods of adjusting the water potential of the substratum were used; both gave qualitatively similar results. Linear growth rate decreased with substratum water potential. The turgor potential at the mycelial front and linear growth rate were positively correlated in both species on both media. An experiment concerned with growth from a medium of high water potential to one of lower water potential and vice versa produced results consistent with those obtained for growth on a single medium.

Yunusa, I.A., Veeragathipillai, M., Eamus, D. & Skilbeck, C.G. 2007, 'Economic and environmental advantages of using fly ash as a soil amendment in agronomy', WSEAS International Conference on Environment, Ecosystems and Development, Tenerife, Spain, December 2006 in Environmental Science, Ecosystems & Development: Proceedings of the 5th WSEAS International Conference on Environment, Ecosystems and Development, ed Otesteanu M; Celikyay S; Mastorakis N; Lache S; Benra FK, World Scientific and Engineering Academy and Society, USA, pp. 294-302.
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Yunusa, I.A., De Silva, D.L., Odeh, I., Eamus, D. 2004, 'Imbalance water-use in farming systems: the potential for bamboo', Salinity Solutions Working with Science, Bendigo, Australia, August 2004 in Salinity Solutions Conference, ed Ridley A; Feikema P; Bennett S; Rogers MJ; Wilkinson R; Hirth J, CRC Dryland Salinity, Bendigo, Australia, pp. 1-5.
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Currently there are few perennials that can maintian all-season water-use and provide ongoing economic benefit in dryland cropping systems. The effectiveness of lucerne in clayey soils and in high rainfall environments has been inconsistent, while the economic potential of native woody species is still uncertain. We suggest in this short discussion the need to explore the use of suitable bamboo species for their rapid growth rates and, hence, water requirement, as well as for their economic benefits. Furthermore, from their morphology we expect bamboos to have a greater capability to open-up dence subsoils to benefit other crops in rotations than the herbaceous species. Out limited undertsnading of the physiology of bamboos is recognised as a major knowledge-gap.