Radial patterns of sap flux densities, demonstrating partitioning in the stem of water taken up from eastern (thick black lines) and western (thick grey lines) roots before (full lines) and after (dashed lines) the severing of the lateral branch. Thin black lines characterize mean profiles of water uptake before and after the treatment. See also Figure 4 for details. R_xyl means stem radius in a measured place without bark thickness.