The Density of Viable Seed in Soils of Forest Plantations in Upland Britain

(1) Viable seed in soils of forest plantations was studied by spreading samples of soil in seed trays and recording the number of seedlings that germinated. (2) Numerous seedlings emerged from most samples; it was concluded that many seeds had survived in the soil for at least 30 yr, and in one case probably for about 45 yr. (3) In 30-40-year-old plantations, seed density was typically 1000-5000 seeds m-2 on brown earths, 500-2500 on peaty gleys and 50-250 on deep peat. In younger plantations the seed density was higher, especially on deep peat. (4) Calluna vulgaris was much the most abundant species. Carex spp. (mostly C. binervis and C. pilulifera), Erica tetralix, Galium saxatile, Juncus effusus and J. squarrosus were also frequent in soils of older plantations, together with Agrostis canina and A. tenuis on brown earths. (5) There was apparently no long-term survival of seeds of Betula spp., Deschampsia flexuosa or conifers. Agrostis canina and A. tenuis survived for several decades but perhaps not for the full length of a normal rotation (50 yr). (6) Development of the vegetation following clear-felling depends mainly on seeds and established plants already present. Immigration is largely confined to species with wind-borne propagules.