THE VEGETATION OF SCOTTISH PINE WOODLANDS AND DUTCH ARTIFICIAL COASTAL PINE FORESTS; WITH SOME REMARKS ON THE ECOLOGY OF LISTERA CORDATA

Coniferous woodland is not indigenous to the semi-humid and subatlantic temperate lowland climatic region of the Netherlands. However, extensive forests of conifers have been planted, mainly since the end of the 18th century. Pinus sylvestris and Picea abies were the main species planted up to the 20th century, but more recently Pseudotsuga menziesii, Larix leptolepis, and to a lesser extent other species have been used. In the coastal dune area, Pinus nigra, both ssp. nigra and ssp. laricio, is the exotic tree that is planted most frequently. From an ecological viewpoint, these forests have not so far been considered as separate plant associations. Since they were mostly lacking in faithful2) species, they have been classified as “cultivated forest communities” under the native deciduous woodland associations, in most cases inside the Querceto-Betuletum (vide e.g. Morzer Bruijns & Westhoff 1951, Westhoff 1954b, 1955, 1957). In the course of the last century, however, some circumborealmontane neophytes have migrated spontaneously into these artificial forests. This has also been observed nearly in Germany (Asgherson & Grabner 1907, Hegi, Schutt 1936 etc.). So far, in the Netherlands Goodyera repens, Linnaea borealis and Lycopodium annotinum were known as such neophytes, though some doubt existed as to whether these species should be considered as “glacial relics”. Goodyera repens, which was not mentioned by Oudemans (1874), was first recorded in the Nctherlands in 1880 in the Leuvenum forest near Hulshorst (Prodromus Florae Batavae ed. altera I, 4, 1916); Linnaea borealis, not yet mentioned in the Prodromus Florae Batavae ed. altera (I, 2, 1903), was recorded first from Appelscha in 1920 and from Floogeveen in 1928 (Beyerinck, 1929b). Beyerinck (l.c.) stated that the latter pine forest dated from 1888 and concluded that Linnaea might have established itself there after 1888. From morphological observations, he estimated the plants to be 26 years old, which means that the species must have been present in 1903, when the pine forest was only 15 years of age. On the other hand Thyen (in Buchenau, 1936, p. 380) observed, that nearby in Germany Linnaea did not occur in woodlands before the pines fruited, the species apparently being introduced by seed devouring birds; Meyer & van Dieken (1947, p. 193) suggest that the trees must be at least 70 years old before Linnaea occurs. At present 12 localities of Linnaea are known in the North Netherlands, viz. 11 in the