The ability of nitrogen-fixing trees, shrubs and herbaceous plants to enhance the growth of conifers interplanted with them on reclamation sites has been examined. There is evidence that these plants can improve tree and site nutrition, but less evidence that useful increases in tree growth will be obtained, at least in early years. Pure stands of alders are successful on a range of substrate types and may be the most sensible choice for very infertile sites unless these can be ameliorated by artificial or organic fertilisers.
