Fróðskaparrit - 01.01.1968, Qupperneq 119

Gróðrarleivdir (sáð) av dvørgabjørk
127
has been able to survive in suitable places scattered around
in the islands for a shorter or longer time.
Perhaps somebody might still think that even 50%> B. nana
might have been blown here from Scotland, Norway and Ice-
land, because the local pollenproduction is so low (Sedum
dominating!). The possibility can however be ruled out in view
of the fact that a procumbent bush like dwarfbirch contri-
butes with much higher pollenpercentages than Pinus and the
treespecies of Betula. In all other analyses I have made from
the Faroes the Betula and Pinus curve follow each other rather
closely, the percentages varying from 5 to 15°/o, ihowever there
is always more Betula than Pinus. This is also the case with
reoent samples, where it is known that all treepollen is long-
distancetransported.
Also the sudden rise and fall of Betula indicates a very
local origin of the pollengrains.
From a radiocarbon dating a little higher up in the profile
ic is concluded that the diagram covers late Preboreal and
early Boreal time. This is confirmed by the Ulmus and Cory-
lus curves.
The purpose of this little paper has only been to demon-
strate the former presence of B. nana in the Faroes. It will
not be discussed ihere why it disappeared, but investigations
will of course continue in order to find out when and why
the dwarfbirch became extinct in the Faroes.
Acknowledgement. During my fieldwork in tthe Faroes, I
got invaluable help from M.Sc. Jóannes Rasmussen, Tórshavn
for which I bring my best thanks. Stategeologist Dr. Johs.
Iversen, who taught me polleanalysis, has always been very
interested in my work. For his help, advice and stimulation
I thank most sincerely.