Conservation value of Norway spruce clearcuts in Walloon region: semi-natural habitat restoration from soil seed bank

Utilisation of Norway spruce (Picea abies) for the valorisation of unproductive land in the Walloon region (southern Belgium) during the second half of the XIXth century has caused dramatic loss of biodiversity. However, it preserved some areas from the general eutrophication due to agriculture intensification. We investigated the reconstituting vegetation on clearcuts of 25 to 50 year old plantations. Vegetation composition is widely in accordance with past extensive land use before Norway spruce plantation and characteristic species are generally well represented. Best-conserved habitats are Calluna heathlands and acidic mires. We also examined the persistent soil seed bank in three standing plantations. Species present in these seed banks are nearly the same as those found in situ in clearcuts. So the potential of these new environments is high in terms of nature restoration and conservation.