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A tree-based approach for modelling interception loss from evergreen oak medite...
Pereira, F.L.; Gasch, J.H.C.; David, J.S.; David, T.S.; Monteiro, P.R.; Valente, F.Evaporation of rainfall intercepted by tree canopies is usually an important part of the overall water balance of forested catchments and there have been many studies dedicated to measuring and modelling rainfall interception loss. These studies have mainly been conducted in dense forests; there have been few studies on the very sparse forests which are common in dry and semi-arid areas. Water resources are sca...
Modelling interception loss from evergreen oak Mediterranean savannas: applicat...
Pereira, F.L.; Gash, J.H.C.; David, J.S.; David, T.S.; Monteiro, P.R.; Valente, F.In a previous study, it was shown that an isolated, fully saturated tree-crown behaves like a wet bulb, allowing evaporation of intercepted rainfall to be estimated by a simple diffusion equation for water vapour. This observation was taken as the basis for a new approach in modelling interception loss fromsavanna-type woodland, whereby the ecosystem evaporation is derived by scaling up the evaporation from ind...
Water-use strategies in two co-occurring Mediterranean evergreen oaks: survivin...
David, T.S.; Henriques, M.O.; Kurz-Besson, C.; Nunes, J.; Valente, F.; Vaz, M,; Pereira, J.S.; Siegwolf, R.; Chaves, M.M.; Gazarini, L.C.; David, J,S.In the Mediterranean evergreen oakwoodlands of southern Portugal, the main tree species are Quercus ilex ssp. rotundifolia Lam. (holm oak) and Quercus suber L. (cork oak). We studied a savannah-type woodland where these species coexist, with the aim of better understanding the mechanisms of tree adaptation to seasonal drought. In both species, seasonal variations in transpiration and predawn leaf water potentia...
Aerodynamic conductances in a sparse mixed oak woodland (Quercus rotundifolia L...
Pereira, F.L.; Valente, F.; Gazarini, L.C.; David, J.S.The study of heat and mass exchange between the vegetation and its local environment plays a central role in the analysis of plant-atmosphere interactions. These studies can be undertaken at different scales, ranging from individual leaves to isolated trees or even the canopy scale. In each of these cases, heat and mass fluxes depend on the use of adequate values of transfer conductances. Within a broader study...
Radiation balance of an isolated holm oak tree (Quercus rotundifolia Lam.) in a...
Pereira, F.L.; Valente, F.; David, J.S.In closed canopy forests the energy absorbed by the trees can be adequately estimated solely from the vertical radiation fluxes. However, in isolated or widely spaced trees this approach is no longer valid and radiation fluxes in all directions must be accounted for. An adequate estimate of the tree available energy is critical to model and calculate both interception losses and transpiration. Within a study wh...
Chorioangioma of the placenta.
Azevedo, M; Serviço de Obstetrícia e Ginecologia do Centro Hospitalar de Gaia.; Barbosa, A; Valente, FChorioangioma is the most frequent nontrophoblastic tumour of the placenta, with a reported incidence ranging from 0.01% to 1.3%. The authors describe three cases of placental chorioangiomas, two of these diagnosed prenatally by ultrasound, and the clinical implications for both mother and fetus. Premature delivery and hydramnios were the obstetric complications associated with these vascular tumours. We confir...
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