<?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%">Gratani, Loretta</style></author><author><style face="normal" font="default" size="100%">Varone, Laura</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Carbon sequestration by Quercus ilex L. and Quercus pubescens Willd. and their contribution to decreasing air temperature in Rome</style></title><secondary-title><style face="normal" font="default" size="100%">Urban Ecosystems</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Carbon Sequestration</style></keyword><keyword><style  face="normal" font="default" size="100%">evergreen and Deciduous species</style></keyword><keyword><style  face="normal" font="default" size="100%">heat island</style></keyword><keyword><style  face="normal" font="default" size="100%">lai</style></keyword><keyword><style  face="normal" font="default" size="100%">tree structure</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year></dates><volume><style face="normal" font="default" size="100%">9</style></volume><pages><style face="normal" font="default" size="100%">27-37</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Carbon sequestration capability by Quercus ilex L and Quercus pubescens Willd., widely distributed in the city of Rome, and their contribution to decreasing air temperature were investigated. Crown volume is the most signiﬁcant (p &lt; 0.01) variable explaining variation of air temperature below the tree crown. Q. pubescens gives a higher contribution to decreasing air temperature during the hottest months, due to its inherent larger crown volume than Q. ilex (252 ± 19 and 533 ± 52 m3 , respectively for the large size). Moreover, our results show the existence of a strong urban carbon dioxide dome with a peak CO2 concentration (on an average 432 ± 37 ppm) at polluted sites, 16% greater than at control sites. Total carbon sequestration is 84 ± 12 and 111 ± 9 Kg year−1 of CO2 for the small Q. ilex and Q. pubescens tree size,respectively, and 151 ± 10 and 185 ± 7 Kg year−1 of CO2 for the large Q. ilex and Q. pubescen tree size, respectively. Q. pubescens, by its higher total photosynthetic leaf surface area (39% higher than Q. ilex) and its higher mean yearly photosynthetic rates (48% higher than Q. ilex) seems to have a greater role than Q. ilex. However, taking into account the leaf longevity (i.e. 12 ± 3 months for Q. ilex and 4 ± 2 months for Q. pubescens), the evergreen species, by its continuous photosynthetic activity, contributes to reduce CO2 throughout the year, and in particular during the winter months, when trafﬁc volume has a pick, than Q. pubescens.</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%">Damesin, C</style></author><author><style face="normal" font="default" size="100%">Rambal, S</style></author><author><style face="normal" font="default" size="100%">Joffre, R</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Between-tree variations in leaf Î´ 13 C of Quercus pubescens and Quercus ilex among Mediterranean habitats with different water availability</style></title><secondary-title><style face="normal" font="default" size="100%">Oecologia</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">carbon isotope composition</style></keyword><keyword><style  face="normal" font="default" size="100%">Foliar chemical constituents</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean oaks</style></keyword><keyword><style  face="normal" font="default" size="100%">tree structure</style></keyword><keyword><style  face="normal" font="default" size="100%">Water availability</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1997</style></year></dates><volume><style face="normal" font="default" size="100%">111</style></volume><pages><style face="normal" font="default" size="100%">26-35</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In this study, sun leaf carbon isotope compo- sition (d 13 C) of two co-occurring woody Mediterranean species (Quercus pubescens Willd., a deciduous oak, and Q. ilex L., an evergreen one) was investigated on four sites with dierent water availability. The total range of d 13 C values was 4.4 and 3.1&amp; for Q. pubescens and Q. ilex respectively. The intra-site variability was about 3&amp;. Total mean per species was equal. There were sig- ni®cant dierences among sites, but at each site means of d 13 C were not signi®cantly dierent between species. A simple physiological model predicts no dierence in in- trinsic water-use eciency (WUEi ) between evergreen and deciduous oaks. The relationship between site means of d 13 C and water parameters suggests that there is a leaf functional adjustment with respect to available water resource. No correlation was found between d 13 C and the contents of any mass-based biochemical cons- tituent. Nevertheless there was a signi®cant correlation between d 13 C and leaf mass per area of Q. ilex. For both species, there is also a positive correlation between leaf d 13 C and individual crown area, i.e. a structural char- acteristic at tree level. Causal relations between d 13 C and plant-environment interactions are discussed.</style></abstract></record></records></xml>