Forest soils in the Mediterranean region frequently have limited rooting depth,
high coarse elements and low organic matter content, which tend to limit water
storage in the soil profile. Accordingly, application of site preparation techniques is
essential to enhance soil water storage and availability in these environments
(Querejeta et al., 2001; Alcázar et al., 2002; Piatek et al., 2003; Imaz et al., 2010).
However, site preparation for afforestation currently lacks accurate planning, based on
sound experimental results driving to techniques most adequate to each situation and
respecting stand productivity and ecosystem sustainability requirements. Improving
soil quality is one of the most important factors for sustaining the global biosphere
and fundamental in forest systems sustainability (Wang and Gong, 1998). A simple
set of established soil properties can provide useful information on soil quality
(Sparling et al., 2004). Soil quality has been defined as “the capacity of a soil to
function within ecosystem boundaries to sustain biological productivity, maintain
environmental quality, and promote plant and animal health'' (Doran and Parkin,
1994). Land use and management practices seriously impact the direction and degree
of soil quality changes in time and space (Wang and Gong, 1998). Possibly the most
significant impact of site preparation from a soil quality perspective is on rooting
depth and soil hydrological processes, because increase the availability of resources
that plants have access (water and nutrients). Runoff and sediment loss is commonly
highest in the first few years after site preparation, for the reason that canopy cover is
scarce and ground vegetation may be insufficient for controlling erosion (Lucci and
Della Lena 1994; Figueiredo et al., 2011).
