Climatic drivers of oak growth over the past one hundred years in mixed and monoculture stands in southern England and northern France

Abstract

In southern England and northern France, pedunculate oak (Quercus robur L.) and sessile oak (Quercus petraea (Matt.) Liebl.) are keystone native species, supporting a substantial diversity of associated species, as well as being a valuable hardwood timber. Future environmental change may require modifications to the ways in which oaks are managed if they are to retain these important roles in forests. Such future management may be informed by past growth patterns using dendrochronological techniques. Oak radial growth between 1900 and 2010 was investigated in five regions in southern England and northern France, together with the impacts of past temperature and precipitation. Additionally, oak growth in monoculture stands and in stands where oak is mixed with Scots pine (Pinus sylvestris L.) was assessed in two forested regions (the New Forest and Thetford Forest) in southern England. This study suggests that oaks in these areas of England and France have shown substantial resilience to past climatic and other environmental factors, with oak growth rates increasing significantly over the twentieth century. Oaks grown in monocultures appeared to grow better than those in mixed stands in the New Forest in southern England; there was no difference in Thetford Forest. Pointer years of unusually good or poor radial growth very rarely coincided between regions in the study area, suggesting that drivers of extreme growth are localised to the region and site-specific drivers, rather than climatic trends in common across the wider area.