Fagus sylvatica as a native tree is confined to south-east England and the midlands, but grows as a result of planting over the rest of Britain (Gamlin, 1985). Although in the past some individuals may have grown naturally in Scotland or northern England and it has now become naturalized there, it is not native in these regions. It is not native in Ireland. The spread of Fagus into more oceanic regions is hampered by the coolness of the summers resulting in the depression of flowering. Its absence from Ireland could be due to the onset of human activity interfering with the natural and unrestricted spread of trees, occurring before Fagus had time to immigrate from England (Tansley, 1939). The greatest dominance of Fagus can be found on calcereous and well drained soils in south-east England (Rodwell 1991). It can also be the dominant tree in southern England wherever there are fertile well drained soils, such as the Chiltern Hills where it forms pure copses. It is probably climatically unsuited to more northern and upland regions of Britain where it would have been unable to compete with Quercus. Modern pollen rain and metereological studies suggest that low winter temperature may be the limiting climatic factor (Huntley et al. 1989).