Carbon Sequestration in Soils Affected by Douglas Fir Reforestation in Apennines (Northern Italy)

Douglas fir reforestation plays an important role in Italian forest because no indigenous conifer has similar characteristics of productivity and timber quality. Few studies on physicochemical properties of soils under Douglas fire are noticeable. The aim of this work is to evaluate the organic C stock into soils under Douglas fir plantation in different selected areas. The areas of study are located in the North Apennine (Italy); Corno alle Scale (COR), Vallombrosa (VAL), Mulino Mengoni (MEN), respectively are chosen for the presence of Douglas fir reforestation of 60 years old. Two soil profiles for each area have been open and described. The pH value decreased along the profile depth. The organic C amount in organic layers was higher in Val and Men pedons than that determined in COR one. Higher amount of organic C were detected in organo-mineral horizons of Co pedons, highlighting a rapid turnover of soil organic matter. The C stock calculated in the first 30 cm of soil showed that the higher C amount is stored in highest altitudes profiles (COR6 and VAL6) than the other. The soil are classified as Lithic Dystrudepts in the highest altitudes (COR 6, 7 and VAL 6, 7, respectively) while as Humic Dystrudepts in MEN (4 and 5) pedons. We conclude that no dangerous effects on soil quality of Douglas fir were investigated and they seem to be similar to those of native tree species, even if other different aspects should be investigated.