Conservation and Sustainable Use of the Biosphere - WBGU

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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

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