Differentiation in adaptive traits between neighbouring bog and mineral soil populations of Scots pine Pinus sylvestris

I used a reciprocal sowing experiment in the field to reveal differentiation in adaptive traits between two neighbouring northern populations of Scots pine Pinus sylvestris. 1 compared a peat bog population with a mineral soil population. Seedling survival was monitored during seven growing seasons and the plants were then harvested to obtain data on pine traits associated with growth and resource allocation, i.e. height, needle length, total dry weight, relative growth, proportion root and proportion needles. Seeds from the peat bog populations had lower germination capacity and were smaller than those from the mineral soil population. Despite their smaller size, the seeds from the bog population were superior for establishment of pines on the bog. On the mineral soil, the traits were strikingly similar in the two pine populations. In contrast, the traits were more variable and differentiated on the bog. Here, the native bog pines grew faster and had a larger proportion root than those originating from the population on the adjacent mineral soil. It is suggested that the differentiation between peat bog populations and mineral soil populations might represent a major direction of differentiation in northern Scots pine populations.