Climate change could drive beech from south-east England

Speaking at a British Ecological Society meeting at Burnham Beeches in Buckinghamshire on Friday 8 September, ecologist Dr Gill Stribley will say: “Our studies of beech trees support the prediction that climate space for beech may disappear in southern England as the climate warms, unless greenhouse gases are stabilised.”

The health of beech trees at representative amenity sites in Surrey has been monitored since 1989 and clear declines of health have been found. According to Stribley: “A tree's health can be assessed by measuring the density of a tree's crown, the extent to which it dies back in summer and changes in twig pattern. In 1992, 40% of large beeches surveyed in Surrey were relatively healthy but by 2002 only 10% were in good shape. We are also concerned that young trees less than 50 years old are showing changes that we would not expect to see until they were around 140.”

Climate change models predict that the UK will have wetter winters but warmer, drier summers, especially in the south-east, and beech seems particularly sensitive to summer droughts, partly because of its relatively shallow, wide-spreading root system. Sensitivity also depends on soil conditions where the beech trees are growing – deep loams and underlying chalk may help to keep the trees better supplied with moisture throughout a dry summer, while shallow or water-logged soils can increase the drought risk.

Dr Keith Kirby of English Nature will tell the meeting that on some sites, especially in the extreme south-east (Kent and Sussex), beech will become increasingly stressed by the effects of climate change. “More trees may die and other species such as oak and ash will be able to compete more effectively with the beech. So the composition of the tree and shrub layers will change – although not necessarily everywhere – and this will have effects on the composition of other plants and animals that live in beech woodland,” Kirby says.

As well as making the south-east less beech friendly, climate change will also make areas further north and west in Britain more suitable for beech, raising the question of whether conservationists should be accepting the spread of beech in these areas. According to Kirby: “We need to recognise that the plant and animal communities that we have at present in our woods will alter as a result of climate change. Nature conservation managers need to factor the likely effects of climate change over the next 100 years into their conservation policies and practice.”