Hydraulic redistribution of soil water in two old-growth coniferous forests: quantifying patterns and controls.

Abstract

We incorporated soil/plant biophysical properties into a simple model to predict seasonal trajectories of hydraulic redistribution (HR). We measured soil water content, water potential root conductivity, and climate across multiple years in two old-growth coniferous forests. The HR variability within sites (0 to 0.5 mm/d) was linked to spatial patterns of roots, soil moisture, and climate. The HR seasonally accounted for up to 9 percent of daily water use, peaking at 0.16 mm/d (ponderosa pine) or 0.30 mm/d(Douglas-fir), then declining as modeled pathway conductance dropped with increasing root cavitation. Patterns of HR were attributed to variability in water potential gradients and conductivity within the root system.

Citation

Warren, J.M.; Meinzer, F.C.; Brooks, J.R.; Domec, J.-C.; Coulombe, R. 2006. Hydraulic redistribution of soil water in two old-growth coniferous forests: quantifying patterns and controls. New Phytologist. 173: 753-765