Restoration of forests - Restoration Ecology - page 140

Impatiens parviflora , Impatiens glandulifera and some structural features are different (causing dif-

ferences in species richness and evenness). Solidago canadensis ).

In Europe the site potential is good for forest
ecosystems nearly everywhere (section 10.1). Despite
the changed (and still changing) conditions, the main
units of European forest vegetation (on the association
level) as described in the past will still exist in the
decades to come; therefore, they can be used as
reference for forest restoration. Box 10.1 summarizes
the recent situation as well as restoration options for
these forest types.
The degree of divergence between the recent vegeta-
tion on the one hand and the site potential (PNV) on
the other hand can be rather different:

In contrast to most of the semi-natural ecosystems in
the European cultural landscape - rough meadows,
heathlands, wetlands, shrublands and the Mediter-
ranean garrigue - restoration of forests is possible with-
out any input from humans: if there is enough time,
a forest ecosystem will establish by itself. However,
the newly establishing or regenerating forest stands
today have to fulfil several valuable functions
(section 10.2.2). Therefore, usually there is no time
available for management-free stand development,
and we have to accelerate the developmental process.
The most important aspects to consider are: the use
of native tree species, use of site-adapted species, inclu-
sion of natural processes in management plans and
inclusion of remains of former larger forest stands in
restored forest landscapes. As has been pointed
out (Ammer & Pröbstl 1988, EC 1992b), within the
implementation phase of the EU directive on refor-
estation of agricultural land the reforestation of
marginal soils may lead to conflicts with nature con-
servation, because such marginal sites often harbour
the remains of anthropogenic ecosystems of the his-
torical cultural landscape. These considerations have
to be taken into account to achieve a general social
agreement on the objectives and implementations of
forest-restoration projects.

• on sterile sediment or bedrock material in large open-
cast mining areas recent ecosystems are far from
the site potential; the soil is poorly developed, and
the organisms (plants, animals, micro-organisms)
forming the ecosystem are missing;
• on abandoned arable fields there is well developed
soil; organisms, although not typical for forests, are
present;
• tree plantations belong to forest formation, and a
lot of characteristic forest organisms are present,
although species composition, structure and processes
are significantly different from primeval forests;
• in close-to-nature forests the spectrum of species is
similar to that expected in a primeval forest, but