Sap Flow and Stem Respiration

Abstract

The effects of seasonal flooding on stem xylem flow and carbon release were investigated on common tree species of the Amazonian floodplain forests locally known as Várzea. The annual flooding lasts several months, reaches five to eight meters and drives the phenology of most forest species. Leaf shedding of deciduous trees starts at the onset of flooding and new leaves are produced after the peak of flooding in July. For evergreen species leaf shedding and new leaf production occur simultaneously during flooding. It has been generally assumed that these phenology patterns are associated to physiological stress during flooding. Here the focus is on tree and species functioning during water stress by flooding. Measurements of stem xylem flux and stem carbon release were taken to monitor changes in species ecophysiological behavior during flooding.