Jökull - 01.12.1993, Blaðsíða 22

DRIFTWOODINICELAND
Kristjánsson (1980) discussed in detail the useful-
ness of the driftwood to the Icelanders in earlier times
and refers to the Icelandic literature that deals with
driftwood.
When the vikings colonized Iceland at the begin-
ning of the 9th century the lowlands were covered
with birch forest. The wood was used as fuel and the
domestic animals grazed on the seedlings, so that the
sensitive birch forest was soon destroyed. The only
wood that was left was the driftwood on the beaches
and probably became the most important material for
houses, boats, bridges, farm implements and house-
holdutensils (Kristjánsson, 1980). The oldest written
records such as lawbooks contain many references to
driftwood. All owners of driftwood bearing beaches
were required to have their personal driftwood mark.
The logs were marked so that the owner might claim
them if they were carried out to sea and redeposited
on somebody else’s beach (Kristjánsson, 1980).
In many places on the extensive coastline of Ice-
land a great deal of driftwood has been washed ashore
and many place-names bear witness to this. The drift-
wood input varies from place to place but at present,
driftwood can be found on nearly every beach. Today,
driftwood is occasionally still used for buildings, but
mostly it is turned into fence posts. Driftwood is now
most common in the depopulated areas of the Vest-
firðir peninsula in the northwest and on Langanes in
the northeast (Figure 1).
The origin of the Icelandic driftwood has been un-
clear. Some people thought it reasonable to conclude
that the wood originated from the south because it was
difficult for them to imagine that the wood was from
the "cold" north. The name "Red Wood" (Rauðviður)
was commonly used (and still is) by farmers on red-
dish driftwood and they assumed that it had drifted
from America. Olavius (1780) studied the wood and
concluded that the "Red Wood" was in fact Larix that
probably originated in Siberia.
Inliteraturefromthe 16th, 17thand 18thcenturies,
the view is often expressed that if it had not been
for the driftwood, Iceland would have proved almost
uninhabitable (Kristjánsson, 1980).
METHODS
IDENTIFICATION OF THE DRIFTWOOD TREE
SPECIES
Trees can often be identified by macroscopic char-
acteristics, particulary the colour and morphology of
the bark. Such characteristics are generally destroyed
in fossil and subfossil wood, but recent driftwood logs
are often well preserved, except that in most cases
the bark has been eroded. However, occasionally bark
may be preserved in combination with the root system.
Only a few species or species groups can be identified
with the aid of a magnifying glass. In coniferous wood
it is only possible to distinguish the species which have
resin canals (Picea, Larix, Pinus) from those which do
not (Abies, Taxus, Juniperus).
On an Arctic driftwood beach it is often possi-
ble to identify Larix from the other driftwood species
because of the reddish colour of the Larix wood.
Sometimes it is possible to distinguish between
Pinus and Picea based on the morphology of the stem
(trunk). It is common for Picea to have many more
twigs on the stem than Pinus. From the morphology
of the root system it is possible to see if the tree has
been growing on permafrost ground with a shallow or
a deep active layer (the soil horizon that thaws during
summer). The penetration of the root system of trees
growing on permafrost depends on the thickness of
this active layer. If the layer is thin the root system is
ílat and vice-versa. The most exact method available
to identify the driftwood tree species, used here, is
to analyse with a microscope the anatomical charac-
teristics of the wood (e.g. Schweingruber, 1978). The
anatomical differences between Pinus and Picea/Larix
are distinct. The differentiation of Picea and Larix is
not as easy (Bartholin, 1979), although, for exam-
ple, colour can help distinguishing between these two
species. Table 1 summarises the main anatomical dif-
ferences of the most common driftwood species.
In some publications (e.g. Eurola, 1971) different
species of Picea and Larix have been distinguished.
For example, Leif M. Paulssen in Norway identified
Picea mariana, which originates in the boreal forests
of Canada and Alaska, together with Larixgmelini and
Larix sibirica in driftwood collections from a raised
20 JÖKULL,No. 43, 1993