Vertical distribution of fine root density, length density, area index andmean diameter in a Quercus ilex forest

We used minirhizotrons to determine the vertical distribution of fine roots in a helm oak (Quercus ilex L.) forest in a typical Mediterranean area ove r a 3-year period (June 1994-March 1997). We measured fine root density (nu mber of roots per unit area), fine root length density (length of roots per unit area), fine root area index (area of roots per unit area) and fine ro ot mean diameter. Variables were pooled for each IO-cm depth interval to a depth of 60 cm. Fine roots tended to decrease with increasing depth except between 0 and 10 cm, where the values of all fine root variables were less than in the 10-cm stratum below. Fine root Vertical distribution was compar ed with soil water content and soil temperature at different depths in the soil profile.