Responses of sap flux and stomatal conductance of Pinus taeda L. trees to stepwise reductions in leaf area

and other hydraulic parameters. Increased gas exchange rates have been commonly observed in response to defoliHerbivory or artificial foliage removal has been shown ation in a range of species (McNaughton, 1983; Gold to affect gas exchange and canopy water relations. In and Caldwell, 1989; Welter, 1989; Reich et al., 1993). this study, canopy architecture and water relations in While defoliation experiments have often focused on response to progressive defoliation were examined in assimilation and growth (Alderfer and Eagles, 1976; a stand of 8-year-old loblolly pine (Pinus taeda L.) Wallace et al., 1984; Belsky, 1986), eVects on g