In the UK, coastal sand-dune pine plantations (predominantly comprising non-native tree species e.g. Corsican pine Pinus nigra) often have little conservation value (although there are notable exceptions). This paper investigated vegetation and soil changes following clear-felling to restore open sand-dune habitats at nine sites in England, Scotland and Wales.
There were two main National Nature Reserve (NNR) study sites (additional observations made at seven other scattered localities):
1) Ainsdale Sand Dunes NNR, Merseyside (planted 1900-1930: felled 1941-1989), northwest England;
2) Whiteford Burrows NNR (planted 1955-1964: felled 1973-1978), West Glamorgan, south Wales.
Soil chemical analysis: At Ainsdale and Whiteford, soil samples from clear-felled sites were compared with those of plantations and open dunes.
Litter decomposition: At Ainsdale, litter decomposition rates were investigated following tree removal. Air-dried cones, twigs and three types of litter from a 70-year-old plantation of P.nigra were each placed into four 15 × 15 cm (1 mm nylon mesh) bags placed in a simulated post-felling environment from August 1989 to May 1991.
Seed bank: At Ainsdale commencing 25 August 1988, soil seed-banks in three unplanted grey dune areas and three afforested (62-year-old plantation) dune sites were compared using a greenhouse germination assay to estimate numbers of viable seeds. Pine regeneration was also assessed.
Germination: At Whiteford, the effect of accumulated organic surface matter (pine litter) on germination of dune plants was investigated. Organic material was removed from a 6 x 6 m plot in a recently clear-felled area in a 30-year-old plantation, in November 1988. Vegetation establishment was assessed in summer 1989.
Often after tree clearance, weed communities (characterised by groundsels and ragworts Senecio spp. and rosebay willow-herb Chamerion angustifolium) established. In clear-felled (especially younger plantation) sites, the weed flora may be gradually replaced by typical dune species. In older cleared plantations (more accumulated litter) there was a tendency towards bryophyte and lichen communities developing, frequently with some pine regeneration and birch Betula spp. invasion.
Pine litter enriched the sandy soils by retaining nutrients and enhanced soil moisture. The seed bank at Ainsdale comprised ruderal (i.e. weedy, non-dune specialist) species. At Whiteford, the accumulated litter layer inhibited germination. Litter removal enhanced re-establishment of open sand-dune plants.
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