CHANGES IN THE COMPOSITION OF MONKS WOOD NATIONAL NATURE RESERVE (CAMBRIDGESHIRE, UK) 1964–1996

Abstract

Summary The composition of Monks Wood, a 157 ha nature reserve in eastern England, in 1964–66 was compared with that in 1996 using data from 36 temporary sample plots distributed systematically across the wood and from a 70 × 35 m permanent sample plot. The overall composition of the wood changed little, but declines in the abundance of Betula pendula, and locally of other species such as Populus tremula had occurred. Both the density of tree stems and of shrub stools declined significantly between 1966 and 1996: for trees from 1469 to 611 stems per hectare, for shrubs from 235 to 177 stools per hectare. Stem basal area also increased. There were substantial changes in the ground flora: reductions in frequency of Mercurialis perennis, increases in Brachypodium sylvaticum, Carex pendula, Glechoma hederacea, Poa trivialis and Urtica dioica. The changes in the tree and shrub layer appear to be mainly a consequence of ‘internal’ factors, stand growth and self-thinning. The ground flora changes reflect a new ‘external’ factor affecting the wood, increases in deer browsing. The die-back of oak Quercus robur recorded over the last six years appears to be a recent phenomenon that needs further monitoring.