Environmental Engineering Reference
In-Depth Information
species in many forest communities and forest stands
there (A. Fischer 1997).
Restoration measures have to be permanently
adapted to ongoing environmental changes. The new
establishing and regenerating forest ecosystems will
not be exactly the same as those that occurred before
the onset of intensive human impact. More woody
species than these, forming tree species mixtures in
late-successional phases such as certain pioneer tree
species, therefore have to be used in reforestation
projects, and all can be found in the native regional
species pool. Introduced species quite often cause prob-
lems which may become obvious only many years after
planting (e.g. see
Robinia pseudacacia
in Box 12.2).
Despite the ongoing changes in site conditions, the
general species composition of the main units of tem-
perate forest vegetation are expected to persist in the
decades to come; therefore, they can be used to con-
struct ecosystems of references for forest restoration.
The most important aspects of forest restoration in a
broad sense throughout the temperate zone remain the
use of native woody species, the use of site-adapted
species, inclusion of natural processes (e.g. using
natural regeneration instead of planting) in manage-
ment plans, and inclusion of remnants of former larger
forest stands in restored forest landscapes.
In this chapter, we have focused on the structure and
species composition of restored or rehabilitated forests,
inspired by the ideal of restoring forest ecosystems to a
state that resembles the 'potential natural vegetation'
as closely as possible. We fully recognize that, in addi-
tion to this general approach, several other aspects
may be important at the local scale, for example urban
forests for recreation, or short-rotation coppices for the
production of renewable energy. Sometimes, but not
always, ecological and socio-economic functions can
be combined. For further reading, we refer to the topic
edited by Mansourian
et al
. (2005), which is based on
WWF's extensive global efforts. It is a source of infor-
mation for both researchers and practitioners on how
forest functions can be integrated into landscape-scale
conservation and restoration plans.
