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FLORA. (65
mentioned before, this wide region may properly be divided into a
northerly and a southerly part, which are delimited from one another in a
natural way by the northern limit of the oak (Quercus pedunculata).
The Northern Region of Coniferous Forest forms the great woodland
of Sweden. Endless expanses are covered with forest, whose monotonous
covering is broken only by desolat moors and by rivers and lakes. It is
only in the coast districts, in the regions below the old marine limit, in the
Silurian of Jämtland and Dalarne, that the forest has to any considerable
extent been compelled to give was’ to agriculture. Seldom, however, does
one come across real primaeval forests: almost everywhere the axe has
interfered. Here, however, the axe has been of less importance in the
development of vegetation than in the southern region of coniferous
forest, as the woodcutting has mostly been carried out by way of
selection the trees and, to a less extent, by clear cutting (a certain number
of seed-trees being left). Of greater importance for the history of the
forests in this part of the country are the forest fires, which — especially
in former days — were very common and laid waste extensive areas.
Together with the pine and the spruce, the common birch (Betula odorato,)
plays a pretty considerable part in the composition of the forests, while the
curled birch (Betula verrucosa) chiefly occurs in the southern parts of the
region and in the coastal districts. With them are found aspen, sallow (Salix
caprea), birdcherry (Prunus padus), rowan (Sorbus aucuparia) and gray alder
(Alnus incana), and in the southern parts of the region the common alder
(Alnus glutinosa). In scattered spots, suitable for vegetation requiring more
warmth, there are found the elm (Ulmus montana), the linden (Tilia ulmifolia),
the maple (Acer platanoides), the ash (Fraxinus excelsior), the hazel (Corylus
Avellana) — principally as remains of a greater distribution in former days.
The vegatation of the coniferous forests is poor in species and monotonous:
the ground-coverings of lichens and mosses and the berry-shrubs determine
the total impression: grasses and herbs are of subordinate importance. Where
the ground is kept moist by running water that is always fresh, or where it is
rich in chalk, however, a fairly luxuriant vegetation of grasses and herbs may
form a pleasant break in the monotonous flora of the coniferous forests. The
various ways in which the constituent parts of the forest are put together,
however, and the different ways in which the ground is covered, have the
consequence that, despite the scanty number of species that characterize the flora
of the coniferous forests of Norrland, different types of forest of quite different
character can be distinguished. In the pine-heaths the trees grow far apart, a flood
of light pours down on to the ground, which thus shines gray-white with lichens,
.forming a covering broken by low dwarf-shrubs such as ling, whortleberries
and crowberry. Pine-heaths dominate the dry sandy plateaus round the rivers
and the drier and more level moraine lands. They have a great extent in the
interior of upper Norrland, in Härjedalen and Northern Dalarne. A richer
impression is given by the mossy pine-forests with their trees often fairly close
together. The lichen covering is there replaced by mosses, among which blueberries
(Myrtillus nigra) figure more conspicuously than on the pine-heaths. Into this type
of wood the spruce easily immigrates, often forming a very slow growing
undergrowth. When the pine does not reproduce itself under the shadow of the spruces
the wood developes into a spruce-forest pure and simple. This mode of
development, however, is often interrupted — this was especially the case in former
5—133179. Sweden. I.
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