The Botany of Iceland - 01.12.1930, Síða 174

164
H. M0LHOLM HANSEN
but without a simultaneous change of the environment in the same
direction. As a matter of fact tlie result is that “the tún burns”
after cold winters and in hot summers, which is due to tlie fact
that in the winter the plants miss the protection afforded by the
jaðar soil, and in the summer its moisture.
Even if a transformation of mo to tún is not as profitable as
the transformation of mýri to tún, it must, however, on the whole
be an advantage to farming. It is, however, questionable whether
this is the right way of cultivating tbe mo. The investigations
described in the present treatise have shown that water is tbe ineans
of protection for southern plants on moist soil, while snow protects
southern plants on the drier soils. Hence if a cultivation of the
mo equally effective to that of the mýri is desired, it should tend
to utilise our knowledge of tlie importance of the snow-covering
rather than aiming at the continued transformation into tún.
The importance of the snow-covering for the southern plants,
and hence for the plants valuable to farmers, has long since been
very thoroughly brought home to all parties concerned.
When the first Icelanders came to the island, c. 874 A. D., the
country was covered with woods “milli fjalls ok fjaru”. This how-
ever, is probably an exaggerated statement, says Thoroddsen,
“but it is quite certain that the lowlands and valleys must have
been more abundantly clothed with copse wood then than now,
even if it must be assumed that large stretches of sandar, mýrar,
and lava fields were also then devoid of woods.” Thoroddsen sup-
poses, however, that when Iceland was first settled, the woods ex-
tended to an altitude of 600 m above sea-level, and tliat, at the
beginning of the lOth century, they covered an area of 4—5000sq.km.
In 1911 the total wooded area had been reduced to 454 sq. km.
According to Helgi Jónsson (1900 p. 76), this great reduction
has been caused by “reckless exploitation”. But by destroying the
trees, the constant snow-covering which was dependent on the pre-
sence of wood was also destroyed and, simultaneously, the luxuriant
forest nndergrowth which was again dejiendent on the snow-covering,
and which formed, entirely or jiartialljq the food of the farm ani-
mals. The great decline in old Icelandic culture, which numerically
resulted in the jjopulation being reduced to half its former number,
must no doubt be directly referred to the destruction of the woods.
The correlalion between these two factors has been outlined above.