Conservation and Sustainable Use of the Biosphere - WBGU

G 3
Disposition of forest ecosystems to the Overexploitation Syndrome
For any analysis of the current dynamic, but above all
to identify regions at risk in the future, it is important
to ascertain what makes an ecosystem disposed to
the Overexploitation Syndrome. In a formal manner,
the concept of the area of disposition provides a
response to the question of the conditions under
which the interactions of the syndrome core are
potentially present (QUESTIONS, 1998). Expressed
in practical terms, the area of disposition covers those
areas of the Earth in which there is a particularly high
probability that the syndrome will emerge in the
future.
Forests are seen as being disposed towards the
Overexploitation Syndrome when the short-term,
large-scale economic use of their wood products is
both possible and probable. Other products of the
forest ecosystems can be ignored in this context if
their extraction does not bring with it the exploitation
of the entire ecosystem. So the disposition is
linked not just to the existence of forests but also to
their potential economic use.This depends on a number
of different factors which will be discussed below.
G 3.1
Disposition factors
The mechanisms characteristic of the Overexploitation
Syndrome can only take hold if forest areas have
a potential economic use.The potential economic use
hinges on the density of the timber or biomass in a
given area and on it being possible to reach those
resources at as reasonable a price as possible. The
relationship between transport costs, land use and
deforestation is well documented (Lambin and
Mertens, 1997; Cassel-Gintz, 1997; Stone, 1998) and
can be explained in economic terms in the tradition
of von Thünen’s theory of land rents (Schätzl, 1988).
The main premise is that land use is determined by
the distance to the point of sale dependent on transportation
costs (including development costs) and
the sales price (Stone, 1998).
The density of biomass that can be put to economic
use was estimated with the help of expert
assessments (Kohlmaier et al, 1997) and a model on
global vegetation dynamics (Sitch et al, 1999) and,
using a compensatory AND-function, linked to
accessible forest resources.A minimum biomass density
required for economic viability is assumed.
The forest data used were taken from the World
Forest Map (WRI, 1998b), that was transformed into
5’ grid cells (around 10 x 10km at the Equator). However
not all forest areas qualified as accessible are
disposed to the syndrome to an equal degree. In
many regions of the world the governments, from
time to time under international agreements, have
established protected forest areas with differing
degrees of limitation on use. Areas with a protected
status of Classes I-V according to the IUCN classification
(Section E 3.3.2) are designated for political
and legal reasons as non-usable. Protection against
illegal logging through designation of protected
areas (eg biosphere reserves under the MAB programme,
Section E 3.9) may often be seen as inadequate
and is dependent on local factors that vary with
time. Thus the estimation of local legal certainty in
these protected areas in the context of short-term
influencing factors is assessed in the context of measuring
intensity (Section G 4) and so is not significant
here.
The accessibility of forests was simulated by
means of a virtual cost calculation.The basic assumption
was that forest areas that can be reached at a low
cost are exploited before those that will take a large
degree of technological and organizational input to
develop and use. In order further to define that input,
a fuzzy logic-based linkage operation was performed
on the following factors:
– proximity to roads and railways,
– proximity to flat coastal areas,
– proximity to urban centres and dense areas of
settlement,
– gradient in the topography of the terrain.
Permafrost areas and navigable rivers with no icefree
ports were categorized as accessible only with
great difficulty. The map that was produced (5’ grid)
indicates the potential accessibility of forest areas
and the relative costs required to develop the area