Ogden: Plant Population Structure and Productivity

In many animal populations age distribution ha.~ been studied as a basic component of population structure. In plants, developmental plasticity and vegetative reproduction may mean that age distribution is less significant than size distribution, particularly in production processes occurring within populaJtions. Changes in size distribution with time and at different densities are discussed, with particular reference to herbaceous monocultures. The relationship between size distribution and 'productive structure' (layering) is considered and examples of the vertical profile of chlorophyll content have been taken from three herb communities. The effects of these population attributes on rates of mortality and turnover, gross production, net production and biomass are discussed and a graphic model is presented which relates aspects of production to density.