Long-term changes in the flora of oak forests and of oak:spruce mixtures following removal of conifers

Abstract

Ground vegetation changes under coppice regimes have been well-described but less work has been done in Britain on the changes that take place under managed high-forest. In 1982/3 60 14.1 × 14.1 m2 quadrats were recorded across stands of oak (Quercus robur L.) and spruce (Picea abies (L.) H.Karst.)/oak mixtures, of various ages in Salcey Forest, Southern England. In 2014 the survey was repeated and changes in the ground flora over this 31-year period in the different crop types were compared. There was a decline in the species richness (number of species per quadrat) in most stands, mainly of species with a high Ellenberg light score, even under mature oak (>100-year old) where no intervention had taken place. Plant species richness increased in stands that had been felled or heavily thinned. The flora of stands where the spruce had been removed leaving a predominantly oak canopy had become similar in richness and individual species frequency to the mature oak crops, supporting the case for restoration of plantations on ancient woodland sites. The changes in the frequency of Woodland specialist plants were similar to those for other woodland species.