Abstract:
CONTEXT : The establishment of mixed stands by intermingling individuals of European beech
and Norway spruce is an ongoing trend in adaptive forest management strategies. However,
our understanding of the potential of these strategies to promote C sequestration remains
limited. AIMS : To assess the effect of species composition on SOC stock in a mixed forest of
Norway spruce and European beech. METHODS : We studied C stocks in the uppermost soil
layers in two stands dominated either by Norway spruce or European beech and in a mixture of both species. We evaluated the effect of litterfall and root turnover on SOC stocks and its
spatial distribution by combining structural equation models and geostatistical techniques.
RESULTS : C stocks in the forest floor were highest in Norway spruce, whereas in the mineral
soil the highest values were in the mixed stand. The proportion of Norway spruce litterfall
was positively related to C stock in the forest floor across stands. Root turnover was
positively related to C stock in the mineral soil of the mixed stand. CONCLUSION : Our results
confirm a contrasting role of root turnover and litterfall between soil layers in the studied
stands, suggesting that tree species composition can mediate the spatial distribution of SOC
stocks in mixed forests.
