Geoscience Reference
In-Depth Information
changes in aquatic plants generally preceded
changes in upland trees, which indicates the
ability of wetland vegetation to respond quickly
to climatic warming, as seeds and plant frag-
ments are carried by migrating waterfowl. As
climate continued to warm during the early
Holocene, the arrival of tree species often did
not correspond to their temperature require-
ments. The timing of tree immigration was
instead determined by rates of dispersal and
locations of glacial refugia from which they
spread (Iversen 1973).
In southern Scandinavia, the Atlantic Period
represents the Holocene thermal maximum
(HTM), and vegetation consisted of a climax
deciduous forest. The following Sub-boreal and
Sub-atlantic periods correspond to the Neogla-
ciation, in which climate became gradually
cooler and wetter. Certainly vegetation responded
to this climatic shift as well as to declining soil
quality as nutrients were depleted. The impact
of early humans becomes more and more
evident during the latter half of the Holocene.
Forests were cleared with axe and i re for
grazing cattle and growing crops, beginning in
the Neolithic (Fig. 9-13) and intensifying during
the Bronze and Iron ages. By the Iron Age,
southern Scandinavia was largely deforested.
Bogs have yielded many archaeological treas-
ures in northern Europe (Fig. 9-14). Among the
most spectacular i nds are so-called bog bodies,
which are, in fact, mummii ed human bodies in
which soft tissues are preserved including skin,
hair, and stomach contents (Fig. 9-15). The best-
preserved bodies come from raised bogs in
which low oxygen and high acidity limited
decomposition and performed a natural tanning
process. For preservation to be successful, the
bodies had to be submerged below water or
buried in peat during the cold season and
covered quickly; the bodies were typically
placed in old peat-digging holes and held down
with sticks or turf (National Museum of Denmark
2010b). Most of the Danish bodies date from the
late Bronze Age or early Iron Age. Many other
bog bodies have been discovered in Ireland,
England, Scotland, the Netherlands, Germany,
and Sweden. It appears that “powerful forces
were at work in the Iron Age society of northern
A
B
Figure 9-13.
Kong Asger's høj, a Neolithic burial
mound, island of Møn, southeastern Denmark. The
Neolithic was the time when agriculture began in
southern Scandinavia. Population grew, society became
more complex, and monumental building projects were
undertaken. A. Overview of mound. B. Interior view of
stone-lined passage that leads to a stone-roofed burial
chamber in the center; height of passage
1 m. Danish
passage graves date from the middle Neolithic,
c.
5000
years ago (Rud 1979). Photos by J.S. Aber.
∼
Europe, and the bog bodies of the period must
have held a special place” (Coles and Coles
1989, p. 196).
As we approach the historical era, the Medi-
eval climate optimum (
c.
AD
700-1200) was a
time of extremely favorable climate in northern
Europe. Harvests were good, i shing was abun-
dant, sea ice stayed far to the north, vineyards
existed 500 km north of their present limits, and
famine was rare (Le Roy Ladurie 1971). This was
the period of great Viking expansions from
Scandinavia. The basis of Viking success was
mastery of wetlands, in particular their ships
which could negotiate inland rivers, estuaries,
