Effects of decomposing beech (Fagus sylvatica) logs on the chemistry of acidified sand and loam soils in two forest reserves in Flanders (northern Belgium)

•Element concentrations increase with decay in CWD, except for C and K.•Soil concentrations of essential nutrients and pH decrease with distance to the log.•Similar trends were found in the moderate and the highly acidic forest site.•Decaying logs can provide a buffering role for various essential nutrients.