Modelling Canopy Gas Exchange During Summer Drought

摘要: The structure and function of woody Mediterranean vegetation is strongly influenced by the periodical occurrence a summer dry period. A hierarchy structural physiological adjustments (e.g. changes in leaf area, rooting depth, stomatal opening), each operating at different time scales (from years to minutes) have been shown be effective mechanisms which sclerophylls cope with limited water availability during these drought periods (Rambal 1993). In holm oak (Quercus ilex L.) canopies, area index (LAI) varies between approximately 2.5 5.5 m2 m-2 depending on long-term site (Table 11.1). Higher LAIs occur areas moderate high annual precipitation, where deep soils minimal drainage ensure soil valley bottom Avic catchment; Sala et al. 1994; Table Lower LAI values precipitation may but low due infiltration limestone substrate) re­tention Puechabon, France; Rambal 1996; Closely re­lated are within-canopy 11.1. Leaf dense stands Basinfunction, improve light environment within canopy can­opy carbon balance (Sala Tenhunen Chap. 9).