For example, the C pool of Austrian forest soils was investigated
using a space-for-time substitution. The underlying hypothesis of the
comparisonwas that spruce forests have a lower soil C pool than forests
of deciduous trees when subsoil horizons are included in the survey.
Chronosequences of 5 to 100 year old spruce (Picea abies), beech
(Fagus sylvatica), and oak (Quercus petraea) forests were compared. A
thick litter layer typically forms under immature spruce because its
needles decompose slowly. However, spruce is known to develop a
shallow rooting system so that the soil C input to the subsoil due to
decaying roots is rather small. The hypothesis was only partially confirmed.
The soil C pool was rather similar in the mineral soil, but the
depth distribution was different. The beech and oak forests had higher
SOC pools in the subsoil whereas spruce forests had most of their SOC
in the upper mineral soil