Re: Fire ecology N and S of the Alps since the last ice age
- From: Eric Stevens <eric.stevens@xxxxxxxxx>
- Date: Thu, 11 May 2006 09:54:26 +1200
On Wed, 10 May 2006 20:32:18 +-0200, "Peter Alaca" <P.Alaca@xxxxxx>
wrote:
Fire ecology north and south of the Alps since the last ice ageThis is interesting. The assumption appears to be that the burning has
Tinner, W; M. Conedera, B. Ammann & AF Lotter
The Holocene, 15( 8) 2005, pp. 1214-1226
http://tinyurl.com/g4zos
(contents page, the pdf is 13 pp, 1.14 mb)
Abstract: Wildfires are very rare in central
Europe, which is probably why fire effects on
vegetation have been neglected by most central
European ecologists and
palaeoecologists.Presently, reconstructions of
fire history and fire ecology are almost absent.
We analysed sediment cores from lakes on the
Swiss Plateau (Lobsigensee and Soppensee)
for pollen and charcoal to investigate the
relationship between vegetation and fire.
Microscopic charcoal evidence suggests
increasing regional fire frequencies during the
Neolithic (7350-4150 cal. BP, 5400-2200 BC)
and the subsequent prehistoric epochs at
Lobsigensee, whereas at Soppensee burnings
remained rather rare until modern times.
Neolithic peaks of charcoal at 6200 and 5500
cal. BP (4250 and 3550 BC) coincided with
declines of pollen of fire-sensitive taxa at both
sites (e.g., Elm, Lime, Ivy, Beech), suggesting
synchronous vegetational responses to fire at
regional scales.
However, correlation analysis between charcoal
and pollen for the period 6600-4400 cal. BP
(4650-2650 BC) revealed no signifi-cant link
between fire and vegetation at Soppensee,
whereas at Lobsigensee increases of Hazel
and decreases of Beach were related to fire
events.
Fire impact on vegetation increased during the
subsequent epochs at both sites. Correlation
analyses of charcoal and pollen data for the
period 4250-1150 cal. BP (2300 BC-AD 800)
suggest that fires were intentionally set to
disrupt forests and to provide open areas for
arable and pastoral farming (e.g., significant
positive correlations between charcoal and
culture indicators).
These results are compared with southern
European records (Lago di Origlio, Lago di
Muzzano), which are situated in particularly
fire-prone environments. Post-Neolithic land-use
practices involving (controlled) burning culmina-
ted in both regions at about 2550 cal. BP (c.
600 BC). However, fire-caused disappearances
of entire forest communities were confined to
the southern sites.
Such differences in fire effects among the sites
are explained by the dissimilar importance of
fire as a result of different climatic conditions
and cultural activities.
been localised and (principally) initiated by man for his own
purposes. However, some years ago the following passage from Jurgen
Spanuth's 'Atlantis of the North' caught my attention.
Begin quote:
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The traces of this burning have been found in Europe also, in
fortresses and settlements, in forests and bogs. All the palaces and
settlements on Crete and the Greek mainland were destroyed by fire -
it is to this we owe the preservation of the Linear B tablets since
they were baked hard and thus could survive the millennia. To quote
all the excavation reports that give the evidence of these
catastrophes would take several pages.
In Macedonia, in what is today Hungary, and in central Germany,
villages and fortified camps were destroyed by great fires at the end
of the thirteenth century. Again and again great masses of cinders
have been found, and often walls and fortifications vitrified by the
heat. C. Schuchhardt said of these: 'They occur everywhere where the
wall of a fortress or a palace was built both of timber and stone such
as basalt, and then burnt' (1941, p. 237f.).
The forests of Europe also burned. For instance, in the sphagnum bogs
of the eastern Alps, which lie 2600m above sea level, the remains of
burnt trees have been found. And regularly in these high mountain bogs
a 'burning horizon' is found, which by pollen analysis can be dated to
'about 1000 BC' (Wilthum 1953, p. 83).
The situation is the same in the sphagnum bogs of the Black Forest,
where Karl Miiller, Professor at the University of Freiburg, examined
burnt strata which he found to lie between the pollen maxima of fir
and beech, and which he placed at 'about 1000 BC.' In the burnt strata
in both these areas are the remains of mountain pines.
Pollen analysis shows that in the Black Forest, after a long period of
warmth and favourable climate, in which the mountains were covered
with beech woods, a time of drier weather followed, in which the beech
woods were replaced by mountain pines characteristic of such a period.
It was these mountain-pine forests that burnt up. They were followed,
in about 1000 BC, by coniferous forest, which is indicative of a
colder and damper climate. K. M+APw-ller wrote: 'Since it is unknown, so
far as I am aware, for mountain-pine forests to catch fire by
lightning, these burnings must have been deliberately caused. However,
as far as we know the upper slopes of the northern Black Forest were
not inhabited at that time, and so it is hard to understand the
purpose of such a burning. The problem of how the burnt stratum
occurred is therefore still unsolved.' (1953.)
This burning horizon with its evidence of terrible fires that raged
3000 years ago is found in all the bogs of Holland, North Germany and
Scandinavia. It regularly occurs just above the 'boundary horizon'
which, as mentioned above, marks the long period of drought in the
thirteenth century. Clearly, the dried-out bogs burned for a long
time.
In Scandinavia the same sequence is found. Here the Bronze1 Age was
the time of'climatic optimum' and the country was thickly forested as
far as the Arctic Circle. Warmth-loving deciduous trees were present
in many places up to the northern coasts. Towards the end of the
Bronze Age, these deciduous woods burnt up, as the burning horizon,
which is found everywhere, attests.
J.G. Andersson said: 'It must have been by fire that the people of
this time began the destruction of nature. But it is hard to know how
far the prehistoric forest fires, whose traces we find constantly, are
to be attributed to human agency, and how far to lightning.' (1914, p.
16.)
So Andersson attributed the destruction of the forests and bogs of
that time to human agency and only brought in the possibility of
lightning as an afterthought.
But why should the people of that time have set fire to the woods on
the mountains of Asia Minor, Greece, the Alps, the Black Forest and
Scandinavia - none of which was then inhabited? Why should they Have
wanted to fire the - often vast - bogs, all of which show the 'burning
horizon' at that time?
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End quote
Spanuth is suggesting some common cause of widespread fire other than
man, lightning etc. I have always wondered how well his observations
of more than 40 years ago have been confirmed by modern research. Is
there evidence to suggest the existence of widespread fires at what
have been the same time?
In writing that last sentence I am well aware of the problems of
determining simultaneity across 3000-4000 years.
Eric Stevens
.
- References:
- Fire ecology N and S of the Alps since the last ice age
- From: Peter Alaca
- Fire ecology N and S of the Alps since the last ice age
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