Seed Viability of Fourteen Species During Five Years of Storage in a Forest Soil

Abstract

(1) Seeds of fourteen species were placed in the mor layer of a north Swedish coniferous forest in autumn 1979. Samples were excavated and tested for viability at intervals until autumn 1984. (2) Three species showed no innate dormancy and germinated to a large extent in the soil: Epilobium angustifolium and Pinus sylvestris were eliminated within one year, but a small fraction of the sample of Deschampsiaflexuosa remained viable for five years. (3) Three others had a strong innate dormancy which was gradually lifted within a few years, resulting in a high degree of germination in the soil: Prunus padus was eliminated within three years but a fraction of Sorbus aucuparia and Trientalis europaea remained viable after five years. (4) For nine species no germination in situ was evident, but viability was generally well maintained over five years. For three of these (Calluna vulgaris, Rubus idaeus and Rumex acetosella) germination was 80-100% after 5 years. (5) For Rubus idaeus and Rumex acetosella there was an increase with storage time in the soil in the proportion of seeds germinating in the laboratory during the first few days after excavation, indicating gradual changes in dormancy characteristics over several years. (6) A proportion of the seeds of Betula pendula, Sorbus aucuparia, Vaccinium myrtillus and V. vitis-idaea had their seed coats partly degraded after five years in the soil, although this had not affected the viability of the seeds. (7) The patterns of depletion observed in the seed populations did not indicate a constant rate of depletion, suggesting that the long-term survival of seeds in boreal forest soils may be very different from that found in many agricultural soils.