Figure 4.

Increased tree mortality in a stream bank of a Quercus ilex forest in Extremadura, SW Spain, where flooding and the oomycete Phytophthora cinnamomi (Pc) co‐occur. (a) Image of the study site showing places of Pc isolation and distribution of living and dead trees. (b) Mean values of water table depth measured in stream banks and upper slopes from March 2009 to February 2011. Assuming sinker roots of Q. ilex growing deeper than 5 m (Moreno et al., 2005), about one‐third of the roots of trees located in stream banks would have been waterlogged for 4 months in 2010 and 2 months in 2011. Bars denote standard errors (n = 5 sites; adapted from Corcobado et al., 2013). (c) Fine roots of Q. ilex trees examined from soil pits (2.5 m wide and 1.5 m deep; n = 288) dug in upper slopes and stream banks. (d) Relative abundance of non‐vital, vital non‐mycorrhizal and vital ectomycorrhizal root tips of Q. ilex trees (n = 192) located in upper slopes and stream banks (n = 48; adapted from Corcobado et al., 2014b). [Color figure can be viewed at wileyonlinelibrary.com]