In this study, we perform water flow simulations for 98 individual
trees over an area of 0.21 ha. Sap flow data from 12 beech
trees within the study stand are used for model evaluation. Furthermore,
we apply a stand-level root water uptake model (RWU
model) to compare the simulated stand transpiration as derived
from the hydraulic single-tree approach with the results ofthe conventional
stand model approach. The main question is whether the
XWF model can account for variations in individual sap flow rates
and thereby improve stand transpiration estimations with respect
to environmental drivers in comparison to the RWU model. Furthermore,
we test whether the species-specific parameterization
of the XWF model as obtained by a previous study (Bittner et al.,
2012a) is valid for the beech stand investigated here.