Jökull - 01.12.1993, Blaðsíða 30

5
<s> m 4 - ■ Picea 1959 1969 1977"
_o "O 0) 1929' 1957 1967 1977"
T3 O 2 - 1928' 1955' 1966* 1977 1982"
o xt E 1927' 1937 1954" 1964' 1976 1981"
Z 1920" 1933 1948 1953 1961 1976 1980"
1929- 1920 1939- 1930 1949- 1940 1959- 1950 1969- 1960 1979- 1970 1989- 1980
Age of the outermost tree ríng in each log
1909- 1919- 1929- 1939- 1949- 1959- 1969- 1979-
1900 1910 1920 1930 1940 1950 1960 1970
Age of the outermost tree ring in each log
Figure 11. Age distribution of driftwood collected in
Iceland and originating in Picea samples are marked
by black square, otherwise Pinus. — Aldursdreifing
rekaviðasýna frá Islandi, sem borist hafafrá svœðinu
umhverfis Hvíta Hafið. Greni er merkt með svörtum
hringjum. Annað erfura.
Figure 12. Age distribution of Pinus driftwood col-
lected in Iceland and originatingin the middle reaches
of the Yenisey river in Siberia. —Aldursdreifing furu
í rekavið frá Islandi, sem borist hafa frá Yenisey í
Síberíu.
draining the forested areas carry the logs into the White
Sea, and then currents transport them to the Barents
Sea where the wood probably gets frozen in sea ice.
The ice is driven by wind and oceanic currents, prob-
ably in an anticlockwise direction to the southernmost
part of Svalbard where it is caught by the branch of
the Norwegian Current that flows north along the west
coast of Spitsbergen (Figure 2). When the log reaches
the Fram Strait - and if it has by then been displaced far
enough westward - the East Greenland Current takes
over and transports it in the eastern part of the cur-
rent (south off the east coast of Greenland), until it is
maybe washed ashore on the north coast of Iceland.
Figure 12 shows the distribution of the ages of
the outermost tree-ring for each of the datable drift-
wood logs from Iceland, which can be correlated with
the mean curve from Langanes. The Langanes curve
(Iceland 1 in Table 3) covers the time span from 1748
to 1973. Most of the trees fitting the mean curve give
a similar date of the last tree-ring in each sample (Fig-
ure 12) indicating that the trees began drifting from
the Yenisey during the period from circa 1940 to 1980.
During the end of the 1960’s drift ice was common on
the northern coasts of Iceland (e.g. Stefánsson, 1981)
and during the same time the amount of driftwood in-
creased. Some of this material might be present as an
increased concentration of some end years in Figure
12. After the second world war the logging industry
in Russia has been concentrated in the areas of the up-
per and middle reaches of the Yenisey river in Siberia
(Eugene Vaganov, pers. comm. 1994), the area where
most of the recent Pinus driftwood in Iceland origi-
nates. The logs fitting the mean curve from site C are
probably transported by the Transpolar Current and
then south along the east coast of Greenland by the
East Greenland Current to Iceland (Figure 2).
28 JÖKULL, No. 43, 1993