Environmental Engineering Reference
In-Depth Information
survived the ice age by migrating to southern Europe,
such as oak (
Quercus
species) and European beech
(
Fagus sylvatica
), while a few species of conifers
survived in the eastern Alps, such as larch (
Larix
decidua
).
At the end of the last ice age, ambient temperature
increased rapidly (Ganopolski & Rahmstorf 2001), and
large areas of Europe again became suitable for tree
growth. Hundreds of pollen diagrams (Lang 1994)
reveal that in central Europe pine (
Pinus
) and birch
(
Betula
) were the fi rst to colonize the land, followed by
oak (
Quercus
) and hazlenut (
Corylus
) migrating to the
north (Huntley 1988). Finally beech (
Fagus sylvatica
)
came to occupy large areas of Europe. Figure 12.2
presents the relatively late but ultimately triumphant
post-glacial procession of beech across Europe. Accord-
ing to site conditions (PNV; see section 12.1), tree
species other than beech as well as forest types other
than beech-dominated forests are restricted to very
limited and rather extreme parts of the extant range of
habitats in central Europe.
Unlike temperate forests in other continents, this
patchy mosaic of European forests never had a chance
to spread and establish itself without human distur-
bance, mainly because after the last ice age humans
conquered the entire European continent. Throughout
central Europe, people started to build permanent set-
tlements during the Neolithic. For this purpose, they
cut down the oak forests that were dominant at that
time, to make way for agriculture and livestock hus-
bandry (K ΓΌ ster 1997 ,
inter alia
). While forests gener-
ally were pushed back more and more, man-made
small-scale disturbances gave new sites for pioneer tree
species like birch and pine. When beech started to colo-
nize the area, many places had already been occupied
by humans.
Fagus sylvatica
recolonizing
500 km
>11
10
9
8
7
6
5
4
3
2
1
0
ka BP
Figure 12.2
European beech (
Fagus sylvatica
) recolonizing Europe after the end of the ice age. Dot size characterizes the time
period since the fi rst record; fi gures are in kiloyears before present (ka BP). Spotted area: recent distribution. Lines: northern
border of distribution in 10 000
BCE
(lower line) and 5000
BCE
(upper line). Modifi ed from Lang (1994), with the permission of
the author.
