Environmental Engineering Reference
In-Depth Information
may require activities like soil amelioration and tree
planting.
(section 10.4.2). The chemical composition of the
atmosphere and, as a consequence, of the soils has
also changed drastically (section 10.4.1). Therefore, the
new establishing and regenerating forest ecosystems
will not be exactly the same as those that stood before
human impact. Besides the changing site conditions
the migration opportunities for species has changed
drastically, too. Many non-woody forest plant species
are so-called
K
strategists: they have a relatively low
generative reproductive potential but often spread
vegetatively; therefore, in an intensively used cul-
tural landscape the chances are small for them to
find new potential habitats. On the other hand
some introduced species were able to establish
self-reproducing populations (e.g.
Prunus serotina
,
10.6 Generalization and concluding
remarks
In a century of intense forest loss, reforestation is an
important aspect of landscape ecology and landscape
management. Human impact has changed site char-
acteristics fundamentally. In many cases soil quality
has decreased, for example due to litter removal in
central Europe or soil erosion in Mediterranean
Europe. The climate has changed during that time, both
by natural processes and as a result of human impact
Box 10.1 The recent situation as well as restoration options for the main European forest
types (units are described in section 10.3).
•
Beech forests
: maintain existing extended beech
forest areas (Fauna, Flora, Habitat Directive EEC/92/
43; EC 1992a). Manage remaining (mixed) beech
forests in selection-cutting or group-selection-cutting
systems. In pine and spruce plantations on sites
with conditions (PNV) for beech forests the portion
of beech should be enlarged. Reforestation of such
sites in flat land often needs pioneer trees as a first
step.
•
Oak and oak-hornbeam forests
: in its natural
distribution area in eastern Europe this type is pro-
tected, for example in the Bialowieza National Park,
Poland. In central Europe it is restricted to places that
are too wet or too dry for beech forests. Large areas
of former oak-hornbeam forests were developed
during the past centuries because of coppicing. Such
stands are not according to the PNV and therefore
their floristic structure are dependent on permanent
human impact.
•
Elder swamp forests
: the remaining limited number
of stands of this forest type must be preserved, prim-
arily its water regime. One ecological problem is humus
mineralization.
•
Riparian forests
: these are extremely degraded by
humans in terms of number (conversion to arable
land, infrastructure) and quality (reduced flooding,
eutrophication). The first step of restoration needs
re-establishment of a flooding regime; secondly
the remains of such forests should be included in
restoration projects.
•
Bolder field forests
: these should be left untouched.
The stands are naturally very small and isolated, access-
ibility for forestry is hard, but biodiversity is high;
recent quality of many of such stands is still close
to primeval.
•
Pine forests
: in central Europe these are very rare
(in the vicinity of raised bogs or on very dry sites).
Natural stands should be preserved. Their productiv-
ity is very low. Boreal forests are managed intensively;
close-to-nature stands need protection. Large-scale
central European pine forests are usually man-made;
a conversion from pure pine to an increasing por-
tion of deciduous trees is proposed.
•
Spruce forests
: according to PNV these are rather rare
in central Europe. Such stands need strict protection
(e.g. Bavarian Forest National Park, south-eastern
Germany). Boreal spruce forests are managed inten-
sively; close-to-nature stands need protection.
•
Mediterranean evergreen sclerophyllous forests
:
nowadays these are rather rare because of long-term
utilization and site degradation. Fire as well as pre-
vention of sheep and goat grazing are the first steps
in a long process of forest restoration. During the
1990s intense reforestation with
Q. suber
and
Q. ilex
(promoted by ECC regulation 2080/92; EC 1992b) took
place. Remaining stands should be protected.
