Spatial heterogeneity is one of the characteristic features of the
soil environment. This is especially true for forest soils, which are
usually not subject to human manipulation over long periods of
time and in which heterogeneity easily develops by uneven litter
decomposition, the tree effect and other factors. While the vertical
stratification of forest soils is widely recognized, the extent of
horizontal heterogeneity has scarcely been addressed (Ettema and
Wardle, 2002). In our previous study, we described a high level
of spatial variability of extracellular enzyme activities and microbial
biomass content in the soil of a hardwood forest (ˇSnajdr et
al., 2008b). The effects of soil moisture on soil microorganisms and
microbial processes are currently a subject of interest due to the
fact that most scenarios for global climate change include changes
in precipitation. It was previously reported that soil moisture content
affects microbial biomass and respiration in the soil, as well
as enzyme-catalyzed processes (Orchard and Cook, 1983; Criquet,