<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">David, Teresa S.</style></author><author><style face="normal" font="default" size="100%">Pinto, Clara A.</style></author><author><style face="normal" font="default" size="100%">Nadezhdina, Nadezhda</style></author><author><style face="normal" font="default" size="100%">Kurz-Besson, Cathy</style></author><author><style face="normal" font="default" size="100%">Henriques, Manuel O.</style></author><author><style face="normal" font="default" size="100%">Quilhó, Teresa</style></author><author><style face="normal" font="default" size="100%">Čermák, Jan</style></author><author><style face="normal" font="default" size="100%">Chaves, M. Manuela</style></author><author><style face="normal" font="default" size="100%">Pereira, João S.</style></author><author><style face="normal" font="default" size="100%">David, Jorge S.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Root functioning, tree water use and hydraulic redistribution in Quercus suber trees: A modeling approach based on root sap flow</style></title><secondary-title><style face="normal" font="default" size="100%">Forest Ecology and Management</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">groundwater</style></keyword><keyword><style  face="normal" font="default" size="100%">soil water</style></keyword><keyword><style  face="normal" font="default" size="100%">Stable isotopes</style></keyword><keyword><style  face="normal" font="default" size="100%">xylem anatomy</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2013///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.sciencedirect.com/science/article/pii/S0378112713004441</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">307</style></volume><pages><style face="normal" font="default" size="100%">136 - 146</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Mediterranean evergreen oaks have to survive a long summer drought. Roots may play a relevant role under these conditions. We studied their structure and function in a mature Quercus suber L. tree in central Portugal. The root system was mapped till the lowest water table level (4.5 m depth). Xylem anatomy was analyzed in a vertical profile belowground. Sap flow was continuously monitored for 1.5 yrs in the stem and roots of this intensively studied tree (heat field deformation method) and in the stem of four trees (Granier method), in relation to environmental variables and predawn leaf water potential. The sources of water uptake were assessed by stable isotope analyses in summer. Results showed a dimorphic root system with a network of superficial roots linked to sinker roots, and a taproot diverting into tangles of deep fine roots submerged for long periods, with parenchyma aerenchyma. Transpiration was not restricted in summer due to root access to groundwater. The isotopic δ18O signature of twig xylem water was similar to that of groundwater in the dry season. Two functional types of superficial roots were identified: shallow connected and deep connected roots. A modeling approach was built considering that each superficial root was linked to a sinker, with part of the root deep connected (between the stem and the sinker) and part shallow connected (between the sinker and topsoil). This conceptual framework simulated tree stem sap flow from root sap flow with a high efficiency (R2 = 0.85) in four plot trees. On an annual basis, soil water and groundwater contributions were 69.5% and 30.5% of stem flow, respectively. Annual hydraulic lift and hydraulic descent were 0.9% and 37.0% of stem flow, respectively. The trees maximize the exploitation of the environmental resources by using the topsoil water during most of the year, and groundwater together with hydraulic lift (nutrient supply) in the dry summer. This study shows that a dimorphic root system, with roots reaching groundwater, is an efficient strategy of Q. suber trees to cope with seasonal drought. Knowledge of the functional behavior of Q. suber trees under shallow water table conditions may contribute to the definition of better adapted management practices and to anticipate their responses to climate change.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Büker, P.</style></author><author><style face="normal" font="default" size="100%">Morrissey, T.</style></author><author><style face="normal" font="default" size="100%">Briolat, A.</style></author><author><style face="normal" font="default" size="100%">Falk, R.</style></author><author><style face="normal" font="default" size="100%">Simpson, D.</style></author><author><style face="normal" font="default" size="100%">Tuovinen, J.-P.</style></author><author><style face="normal" font="default" size="100%">Alonso, R.</style></author><author><style face="normal" font="default" size="100%">Barth, S.</style></author><author><style face="normal" font="default" size="100%">Baumgarten, M.</style></author><author><style face="normal" font="default" size="100%">Grulke, N.</style></author><author><style face="normal" font="default" size="100%">Karlsson, P. E.</style></author><author><style face="normal" font="default" size="100%">King, J.</style></author><author><style face="normal" font="default" size="100%">Lagergren, F.</style></author><author><style face="normal" font="default" size="100%">Matyssek, R.</style></author><author><style face="normal" font="default" size="100%">Nunn, A.</style></author><author><style face="normal" font="default" size="100%">Ogaya, R.</style></author><author><style face="normal" font="default" size="100%">Penuelas, J.</style></author><author><style face="normal" font="default" size="100%">Rhea, L.</style></author><author><style face="normal" font="default" size="100%">Schaub, M.</style></author><author><style face="normal" font="default" size="100%">Uddling, J.</style></author><author><style face="normal" font="default" size="100%">Werner, W.</style></author><author><style face="normal" font="default" size="100%">Emberson, L. D.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">DO3SE modelling of soil moisture to determine ozone flux to forest trees</style></title><secondary-title><style face="normal" font="default" size="100%">Atmospheric Chemistry and Physics</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">DO3SE</style></keyword><keyword><style  face="normal" font="default" size="100%">Drought (voyant)</style></keyword><keyword><style  face="normal" font="default" size="100%">Modeling</style></keyword><keyword><style  face="normal" font="default" size="100%">soil water</style></keyword><keyword><style  face="normal" font="default" size="100%">Stomatal conductance</style></keyword><keyword><style  face="normal" font="default" size="100%">Stomatal ozone ﬂux</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2012</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2012///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.atmos-chem-phys.net/12/5537/2012/</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">12</style></volume><pages><style face="normal" font="default" size="100%">5537 - 5562</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The DO3SE (Deposition of O3 for Stomatal Exchange) model is an established tool for estimating ozone (O3) deposition, stomatal ﬂux and impacts to a variety of vegetation types across Europe. It has been embedded within the EMEP (European Monitoring and Evaluation Programme) photochemical model to provide a policy tool capable of relating the ﬂux-based risk of vegetation damage to O3 precursor emission scenarios for use in policy formulation. A key limitation of regional ﬂux-based risk assessments has been the assumption that soil water deﬁcits are not limiting O3 ﬂux due to the unavailability of evaluated methods for modelling soil water deﬁcits and their inﬂuence on stomatal conductance (gsto), and subsequent O3 ﬂux. This paper describes the development and evaluation of a method to estimate soil moisture status and its inﬂuence on gsto for a variety of forest tree species. This DO3SE soil moisture module uses the Penman-Monteith energy balance method to drive water cycling through the soil-plantatmosphere system and empirical data describing gsto relationships with pre-dawn leaf water status to estimate the biological control of transpiration. We trial four different methods to estimate this biological control of the transpiration stream, which vary from simple methods that relate soil water content or potential directly to gsto, to more complex methods that incorporate hydraulic resistance and plant capacitance that control water ﬂow through the plant system. These methods are evaluated against ﬁeld data describing a variety of soil water variables, gsto and transpiration data for Norway spruce (Picea abies), Scots pine (Pinus sylvestris), birch (Betula pendula), aspen (Populus tremuloides), beech (Fagus sylvatica) and holm oak (Quercus ilex) collected from ten sites across Europe and North America. Modelled estimates of these variables show consistency with observed data when applying the simple empirical methods, with the timing and magnitude of soil drying events being captured well across all sites and reductions in transpiration with the onset of drought being predicted with reasonable accuracy. The more complex methods, which incorporate hydraulic resistance and plant capacitance, perform less well, with predicted drying cycles consistently underestimating the rate and magnitude of water loss from the soil. A sensitivity analysis showed that model performance was strongly dependent upon the local parameterisation of key model drivers such as the maximum gsto, soil texture, root depth and leaf area index. The results suggest that the simple modelling methods that relate gsto directly to soil water content and potential provide adequate estimates of soil moisture and inﬂuence on gsto such that they are suitable to be used to assess the potential risk posed by O3 to forest trees across Europe.</style></abstract><issue><style face="normal" font="default" size="100%">12</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Bellot, J.</style></author><author><style face="normal" font="default" size="100%">Ortiz de Urbina, J. M.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Soil water content at the catchment level and plant water status relationships in a Mediterranean Quercus ilex forest</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Hydrology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Catchments</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant water status</style></keyword><keyword><style  face="normal" font="default" size="100%">Predawn water potential</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">soil water</style></keyword><keyword><style  face="normal" font="default" size="100%">water balance</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2008///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://linkinghub.elsevier.com/retrieve/pii/S0022169408002229</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">357</style></volume><pages><style face="normal" font="default" size="100%">67 - 75</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">This paper presents an analysis of the forest hydrology and plant water status interaction, focusing on the relationship between the hydrological water balance at the catchment level and the predawn leaf water potential of the species Quercus ilex (holm oak). The catchment water balance approach was applied to a Mediterranean watershed forested with holm oak to evaluate the daily soil water reserve at the catchment level. After this, evapotranspiration and soil water content were combined to estimate the potential soil water reserve and evaluate plant water status at the catchment level. A close relationship was detected between leaf water potential and the soil water reserve, and was ﬁtted to a negative exponential curve to estimate predawn leaf water potential from a hydrological database. The proposed equation can help to predict the frequency, intensity, and length of droughts potentially capable of causing structural damage to the forest, from the hydrological time series records.</style></abstract><issue><style face="normal" font="default" size="100%">1-2</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Jarvis, Paul</style></author><author><style face="normal" font="default" size="100%">Rey, Ana</style></author><author><style face="normal" font="default" size="100%">Petsikos, Charalampos</style></author><author><style face="normal" font="default" size="100%">Wingate, Lisa</style></author><author><style face="normal" font="default" size="100%">Rayment, Mark</style></author><author><style face="normal" font="default" size="100%">Pereira, João</style></author><author><style face="normal" font="default" size="100%">Banza, João</style></author><author><style face="normal" font="default" size="100%">David, Jorge</style></author><author><style face="normal" font="default" size="100%">Miglietta, Franco</style></author><author><style face="normal" font="default" size="100%">Borghetti, Marco</style></author><author><style face="normal" font="default" size="100%">Manca, Giovanni</style></author><author><style face="normal" font="default" size="100%">Valentini, Riccardo</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Drying and wetting of Mediterranean soils stimulates decomposition and carbon dioxide emission: the “Birch effect”</style></title><secondary-title><style face="normal" font="default" size="100%">Tree Physiology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">carbon balance</style></keyword><keyword><style  face="normal" font="default" size="100%">carbon mineralization rates</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean climate</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean forest</style></keyword><keyword><style  face="normal" font="default" size="100%">rain pulse</style></keyword><keyword><style  face="normal" font="default" size="100%">soil rewetting</style></keyword><keyword><style  face="normal" font="default" size="100%">Soil temperature</style></keyword><keyword><style  face="normal" font="default" size="100%">soil water</style></keyword><keyword><style  face="normal" font="default" size="100%">summer rainfall events</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2007</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2007///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://treephys.oxfordjournals.org/content/27/7/929.abstract</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">27</style></volume><pages><style face="normal" font="default" size="100%">929 - 940</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Observations on the net carbon exchange of forests in the European Mediterranean region, measured recently by the eddy covariance method, have revived interest in a phenomenon first characterized on agricultural and forest soils in East Africa in the 1950s and 1960s by H. F. Birch and now often referred to as the “Birch effect.” When soils become dry during summer because of lack of rain, as is common in regions with Mediterranean climate, or are dried in the laboratory in controlled conditions, and are then rewetted by precipitation or irrigation, there is a burst of decomposition, mineralization and release of inorganic nitrogen and CO2. In forests in Mediterranean climates in southern Europe, this effect has been observed with eddy covariance techniques and soil respiration chambers at the stand and small plot scales, respectively. Following the early work of Birch, laboratory incubations of soils at controlled temperatures and water contents have been used to characterize CO2 release following the rewetting of dry soils. A simple empirical model based on laboratory incubations demonstrates that the amount of carbon mineralized over one year can be predicted from soil temperature and precipitation regime, provided that carbon lost as CO2 is taken into account. We show that the amount of carbon returned to the atmosphere following soil rewetting can reduce significantly the annual net carbon gain by Mediterranean forests.</style></abstract><issue><style face="normal" font="default" size="100%">7</style></issue><notes><style face="normal" font="default" size="100%">10.1093/treephys/27.7.92910.1093/treephys/27.7.929</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Avila, Anna</style></author><author><style face="normal" font="default" size="100%">Rodrigo, Anselm</style></author><author><style face="normal" font="default" size="100%">Rodà, Ferran</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Nitrogen circulation in a Mediterranean holm oak forest, La Castanya, Montseny, northeastern Spain</style></title><secondary-title><style face="normal" font="default" size="100%">Hydrology and Earth System …</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">ammonium</style></keyword><keyword><style  face="normal" font="default" size="100%">bulk deposition</style></keyword><keyword><style  face="normal" font="default" size="100%">Dry deposition</style></keyword><keyword><style  face="normal" font="default" size="100%">la castanya</style></keyword><keyword><style  face="normal" font="default" size="100%">montseny</style></keyword><keyword><style  face="normal" font="default" size="100%">nitrate</style></keyword><keyword><style  face="normal" font="default" size="100%">soil water</style></keyword><keyword><style  face="normal" font="default" size="100%">Spain</style></keyword><keyword><style  face="normal" font="default" size="100%">throughfall</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2002</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2002///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://hal.archives-ouvertes.fr/hal-00305215/</style></url></web-urls></urls><pages><style face="normal" font="default" size="100%">551 - 558</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Bulk deposition, wet-only deposition, throughfall and dry deposition inferred from washing foliage and surrogate surfaces were used to describe inorganic N inputs to a forested catchment in the Montseny Mountains (La Castanya, Catalonia, Spain). Bulk inputs of inorganic N were moderate, with a mean of 5.7 kg N ha -1 yr -1 , ranging between 4 and 10 kg N ha -1 yr -1 for the period 1983 to 2000. Dry deposition fluxes estimated from washing branches added about 9 kg N ha -1 yr -1 to wet inputs and the total atmospheric deposition was estimated in 15 kg N ha -1 yr -1 . Despite this substantial input flux, nearly all the inorganic nitrogen was retained within the forest ecosystem: NH4 + and NO3 - concentrations decreased dramatically as water crossed the canopy and the soil profile. In the stream, at baseflow conditions, NH4 + and NO3 - concentrations were always below the analytical detection limit (&lt; 2 µeq L -1 ). Only briefly during peak flows did NO3 - concentrations increase up to 100 µeq L -1 . Averaged over 10 years (1984-1994), the export of N at the catchment outlet was 0.05 kg N ha -1 yr -1 . This indicates a very tight N cycling allowing for an increase of N availability in these undisturbed forest ecosystems.</style></abstract><issue><style face="normal" font="default" size="100%">3</style></issue></record></records></xml>