Re: Post-glacial European vegetation development

Daryl Krupa wrote:
news:1156540353.801553.219090@xxxxxxxxxxxxxxxxxxxxxxxxxxxx

Peter Alaca wrote:


Philip said somewhere something,
supposedly in relation to the first neolithic farmers,
about Italy and the Balkans as sources for oaks in
Switzerland.

<snip>
And here is a history of Balkan oak and pine distribution,
with oak being replaced by pine at about the time that
Philip said people were spreading oak from there:

Well, I love the idea of that people taking all the
oak trees with them, leaving a wasteland behind
for the pines to fill in, bud I am afraid it is not true.
At least, I cannot draw that conclussion from Tonkov's
information you so kindly provided.
Again we are talking here about a vertical shift in the
various tree-zones under climatic influences.
There are only indications in this study for human
influence since 3770 cal.BP (see below)

What you (or better: Phil) must understand is, that this
pine business is about (sub) alpine areas, which cannot
be compaired with the areas preferred bij the first (LBK)
farmers.

More below your quote.

Vegetation and climate changes in the high mountains on the Balkan
peninsula (Southeast Europe) in postglacial times

Spassimir Tonkov

see http://tinyurl.com/j7hn9

Pollen and plant macrofossil analyses supplemented by radiocarbon
chronology were conducted on lacustrine sequences from glacial lakes
located in the Rila (2925 m) and Pirin Mountains (2914 m) on the
Balkan peninsula. The vegetation response to the Lateglacial climatic
fluctuations after 13000 14C yrs. BP was characterized by the
widespread of mountain herb vegetation dominated by Artemisia
-Chenopodiaceae - Poaceae with sparse stands of Pinus and shrubland of
Juniperus - Ephedra. The identification of pollen and macrofossil
remains from a number of thermophilous coniferous and deciduous trees
suggests that they survived the harsh climatic conditions in refuges
at lower altitudes where moisture was sufficient for their growth. The
reforestation dynamics in early Holocene times (9600-8800 14C yrs. BP)
after the termination of the stadial Younger Dryas started with Betula
forests and groups of Pinus while deciduous forests with Quercus,
Tilia, Ulmus and Corylus gained dominance at low altitudes between
8800 and 6800 14C yrs. BP. An increase in humidity and precipitation
and the establishment of suitable edaphic conditions after 6800 14C
yrs. BP initiated the formation of a coniferous belt composed of
Pinus and Abies. The forest dynamics in late Holocene ended with the
invasion of Fagus and Picea after 4000 and 3000 14C yrs. BP,
respectively. Indications of long-lasting anthropogenic interference
in the natural forest cover, expansion of agriculture in the
foothills and livestock grazing in the mountain pastures, are clearly
recorded after 2200 14C yrs. BP.

Much more from the same study in:

Spassimir Tonkov & Elena Marinova (2005)
"Pollen and plant macrofossil analyses of radiocarbon
dated mid-Holocene profiles from two subalpine lakes
in the Rila Mountains, Bulgaria"
The Holocene 15(5):663-671
http://tinyurl.com/og7sx
[pdf, 9pp, 1.1Mb]

Conclusions
In the context of the intensive ongoing research
during the last decade on postglacial sequences
in the montane areas of the Balkan peninsula,
the following main conclusions could be drawn
concerning the palaeovegetation reconstruction
in the Central Rila Mountains for the last 6700-
6500 years as a result of the multidisciplinary
approach combining pollen analysis, plant
macrofossil determination and radiocarbon
dating.

(1) The formation of a coniferous vegetation belt
dominated by Pinus sylvestris, Pinus peuce and
Abies alba began after 6700 cal. BP. The
treeline shaped by Pinus sylvestris and Pinus
peuce was higher, up to 2200-2300 m,
compared with the present-day.
Groups of Pinus mugo and Juniperus sibirica
among patches of herb vegetation were
distributed in the subalpine zone.
(2) The mid-Holocene pollen assemblages at low
altitudes were dominated by deciduous trees
(Quercetum mixtum-Corylus phase) that lasted
until c. 6000 cal. BP.
(3) The wide distribution of Abies alba in the
lower part of the coniferous belt was confined to
the time window 6000-2800 cal. BP, i.e., during
the sub-Boreal, with a maximum at c. 3800 cal.
BP.
(4) The establishment of Fagus sylvatica and
Picea abies took place at c. 6500 and 4500 cal.
BP, respectively. Both tree species began
gradually to enlarge their areas after 3800-3500
cal. BP. The final expansion of the beech forests
at low altitudes took place c. 500-400 cal. BP,
coincident with the climate cooling during the
'Little Ice Age'.
(5) Traces of human impact are continuously
registered in the pollen and plant macrofossil
records since 3770 cal. BP. In historical times
the changes in the vegetation cover at higher
altitudes, and the lowering of the treeline, were
primarily caused by increasing anthropogenic
activities, indicating livestock-grazing and
burning of dwarf-pine (Pinus mugo).

--
p.a.


.

Loading