http://www.researchonline.mq.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:15563 The impact of drought on tree water use was investigated in remnant forest in the Liverpool Plains NSW. Tree water use was measured using commercial sap flow testers from December 2002 to September 2004 which corresponded with a period of drought and a period of higher rainfall. Understorey evapotranspiration and soil moisture were also measured. Water use of the stand of trees was a larger proportion of annual total rainfall (87%) during the drought period than during the post-drought period (50% water use) when rainfall was higher. Understorey water use was about 20% of rainfall, suggesting that the understorey evapotranspiration component of the water balance can make a significant contribution to water use and the availability of water for groundwater recharge. The results indicate that the remnant forest was able to survive during the drought because of deep roots. The findings also demonstrate the valuable role forests play in maintaining the hydrological balance and in ameliorating the development of dryland salinity in agricultural areas (A). 2011-11-16T21:43:24.014Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:11874 Published online: 17 June 2009. 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 information across continental Australia. We quantified vertical and horizontal root biomass distribution in a woodland dominated by Angophora bakeri and Eucalyptus sclerophylla on the Cumberland Plains near Richmond, New South Wales. The site was characterised by a duplex (texture contrast) soil with the A horizon (to 70 cm) consisting of loamy sand and the B horizon (to < 10 m) consisting of sandy clay. The topsoil had a smaller bulk density, a smaller water holding capacity but a larger organic component and a larger hydraulic conductivity in comparison to the subsoil. Root biomass was sampled to 1.5 m depth and declined through the soil profile. Whilst total biomass in the B horizon was relatively small, its contribution to the function of the trees was highly significant. Coarse roots accounted for approximately 82% of the root mass recovered. Lateral distribution of fine roots was generally even but coarse roots were more likely to occur closer to tree stems. Variation in tree diameter explained 75% of the variation in total below-ground biomass. The trench method suggested the belowground biomass was 6.03 ± 1.21 kg m⁻² but this method created bias towards sampling close to tree stems. We found that approximately 68% of root material was within a 2 m radius of tree stems and this made up 54% of the total number of samples but in reality, only approximately 5 to 10% of the site is within a 2 m radius of tree stems. Based on these proportions, our recalculated belowground biomass was 2.93 ± 0.59 kg m⁻². These measurements provide valuable data for modeling of ecosystem water use and productivity. 2011-02-18T00:10:33.861Z ]]>