What is ancient semi-natural woodland?
Ancient semi-natural woodland (ASNW) has developed naturally on undisturbed soils. The long continuity of semi-natural ancient woods and their undisturbed soils makes it the most valuable natural habitat.
It supports a huge range of wildlife (including more threatened species than any other UK habitat) many of which require stable conditions (i.e. relatively unchanging compared to land outside the woods). Often, these species are unable to move easily so do not colonise new areas easily.
According to the UK's Biodiversity Action Plan, in the last 100 years, 46 species of broadleaved woodland have become extinct in the UK.
Woods planted or growing up today will not become ancient woods in 400 years’ time because the soils on which they have developed have been modified by modern agriculture or industry, and the fragmentation of natural habitats in today’s landscape hampers species' natural movements and interactions.
Our remaining semi-natural ancient woodland is therefore irreplaceable. If we lose what little we have left then it is gone forever.