How long can young Scots pine seedlings survive waterlogging?

The aim of this study was to clarify the capability of Scots pine seeds (Pinus sylvestris L.) of different origins to germinate and survive under waterlogging conditions. Seeds were used from one Spanish and three UK sources. All experiments were carried out in the glasshouse and under the optimum conditions for Scots pine seed to germinate and establish. A technique using inner and outer pots was used to produce four depths of waterlogging below the soil surface. Seed mass and viability were examined prior to use in the experiments. Waterlogging reduced germination, but an increase in time between sowing and waterlogging of up to 3 weeks and a watertable > 4 cm below the surface greatly improved germination and seedling growth. Once established, seedling survival was remarkably tolerant of waterlogging, and seedlings survived 25 months even with the watertable at the soil surface. Seeds collected from trees on a floating bog in the English Midlands were least affected by waterlogging, but the variation among seed sources was small compared to the effects of the timing, depth and duration of waterlogging. Management implications are discussed.