Many studies
have examined the changes in tree resistance related to drought
and variation in gas exchange and transpiration relationships
between Ktree and Gs (e.g., Hubbard et al., 2001; Meinzer, 2002;
Domec et al., 2009a), yet the causes of variation in Ktree are rarely
studied. Here we show that drought-induced differences in the
whole hydraulic apparatus of the soil plant system of all species
were largely a reflection of the loss of root conductivity over a wide
range of soil water potentials