Nicola Arndt und Matthias Pohl - Neobiota

Figure 2: Potential natural vegetation of Denmark: Relative area occupied by the main groups of
vegetation units.
2.1 Forest units
The forests include seven units. The most important units on dry soil are F108 (meso-eutrophic beech
forest), mostly on clayey moraine in the southeastern part of the country, F79 (oligotrophic beech
stationary line of the ice during the Weichsel glaciation. The area covered by beech forest constitutes
forest), mostly on sandy, leached moraines and raised sea-floors in the western and northern part of the
country, and F8 (oligotrophic birch-oak forest), on sandy outwash plains to the west of the main about
76 % in total.
Two forest units are found exclusively on moist or wet soil: T1 (alder woodlands), mostly along lakes
and in wet glacial and late glacial valleys, but of which only some of the more important potential
occurrences are depicted in the European map, and U28 (polder forests), predicted as being the natural
type of vegetation of reclaimed, low-lying coastal areas.
Two units that occupy only small areas, but for which the Danish occurrences represent their major
distribution in the European map, are F37 (oak-hornbeam forest) and F109 (beech forest on calcareous
soil).
The south Scandinavian oak-hornbeam forest is restricted to southern Lolland and Bornholm.
Hornbeam (Carpinus betulus) grows wild in the southeastern part of the country (Figure 3A), probably
due to relatively high summer temperatures, and on southern Lolland is furthermore favoured by
heavy clays (MØLLER & STAUN 1998). Acer campestre, an important understorey shrub in the oakhornbeam
forest, is even more restricted to the southeastern part of the country (Figure 3B). The
occurrence of the oak-hornbeam forest on the isle of Bornholm in the Baltic may be seen in connection
with the scattered occurrences in southeastern Sweden.
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