Since the 1950s, Fraxinus excelsior has colonized the open areas. Tree growth was
estimated from comparison of diameter/girth measurements from 1968 and 2007. F. excelsior
diameter increment was greater than that of Acer pseudoplatanus and both showed faster
growth than Quercus robur. Some canopy trees died, but no large gaps formed in the
closed woodland. The abundance of understorey stems declined. The current stand structure
reflects effects of past management, browsing pressure and climatic stresses over
the last four decades. Multiple causes of change are probably commoner than single
factors in explaining woodland structure.