Rehabilitation and Restoration Of Degraded Forests (PDF) - IUCN

Large areas of the world’s forests have been lost or degraded and
landscapes everywhere are being simplified by current land-use
practices (Dobson, Bradshaw and Baker 1997). In many tropical
countries increasing areas of forest or woodland are cleared for agricultural
use. The same is true in some temperate countries although, for
the most part, land-use patterns there have stabilized over the last
century. In many temperate countries, however, agricultural practices
are intensifying. Small family-owned farms are being replaced by larger
industrial operations owned by corporations, and forest remnants and
hedgerows are being removed to allow for larger-scale operations. In
both tropical and temperate regions, therefore, landscapes are being
homogenized. Ironically, there are also increasing areas of abandoned
land in both tropical and temperate areas. In some cases the previous
forms of agriculture were unsustainable and farmland was abandoned
when productivity declined. In other cases, particularly in western
Europe, social and economic changes (including reductions in agricultural
subsidies) have led to the abandonment of previously productive
agricultural land.
Agricultural expansion and intensification have decreased the overall
area of forest and woodland, simplified the structure of the remaining
forests and broken up forest areas into smaller and more isolated
fragments. The consequences of these changes, seen both on-site and
off-site, include the following:
• on-site reductions in landscape productivity because of increasing
losses of nutrients and soil;
• downstream impacts, such as reductions in water quality through
increased sedimentation and changes in water yield; and
• widespread reductions in biodiversity and the supply of various
ecological goods and services.
Such changes, and others likely to occur in the near future, are
described by Vitousek et al. (1997) and Tilman et al. (2001). In some
cases the effects of a loss of forest cover (e.g. erosion) are almost
immediate. Other changes (e.g. salinisation, biodiversity loss) take a
long time to become evident. The cumulative effects of the release of
carbon once sequestered in biomass and soil organic matter are likely
to contribute to long-term changes in the global climate.
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Chapter 1
Introduction