Causes for the small scale variability of nitrate concentration in seepage water of an N saturated mature spruce stand

Context In N-saturated forests nitrate concentrations in seepage water (\( {\text{N}}{{\text{O}}_3}{^{ - }_{\text{seepage}}} \)) regularly show high spatial variability even within homogeneous stands. Up to now the reasons of this variability are not fully understood.