Ecosystems are complex arrangements of living organisms interacting with each other and with their physical environment. In attempts to understand such systems man groups their components into a number of more or less easily defined categories such as species or herbs and shrubs. Depending on the nature of the grouping this treatment necessarily leads to a loss of information which may affect our understanding of the ecosystem. Thus in the past production studies of forest stands have included, with few exceptions, composite weights of the understorey vegetation. Ovington (1956) has pointed out that it may be useful to consider species individually and, to a limited extent, this has been attempted here. The data were collected as part of a study of the growth and nutrition of a coppice stand of ash (Fraxinus excelsior) growing on a poorly drained Hanslope soil developed on chalky boulder clay (Hodge 1963) in Monks Wood National Nature Reserve. The main object was to determine the amounts of major nutrients in the understorey vegetation but the opportunity was taken to obtain some data on the variations between species.