DEFORESTATION AROUND THE WORLD - India Environment Portal

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Deforestation Around the World
gaseous losses than upslope soils (Matson et al. 1991). Therefore, on geological timescales,
landslides help produce stable land suitable for agricultural and habitation (for tropical
islands, also tourism) and provide materials that form fertile plains and valleys, beaches,
and barrier islands. However, on a scale typical of a human life span, the benefits accruing
from landslides are overshadowed by their destructive characteristics; they are hazards that
should be understood and mitigated as much as possible.
While it is reasonable to generalize that landslide activity is important, landslide impact on
deforestation, on ecosystems in general, have not been well addressed. The following
comments are not an exhaustive review but are intended to indicate the relevance of
landslides to deforestation.
Fig. 1. Global distribution of Net Primary Production (NPP, color shading, in g/m 2/yr) and
occurrence (red crosses) of storm-triggered landslides (2003-2007).
The main geological hazards of volcanic activity, earthquakes and landslides are commonly,
but not entirely, associated with processes occurring in areas near subduction zones. It is
there that elevations are high enough to generate instability and sources of hazardous
agents are abundant. This explains why the landslides belt coincides with the Earth’s major
earthquake belts. The Himalayas, for example is a hot spot (Figure 1). Figure 1 shows the
primary landslides that are deeper than 2.5 m thick and contain >10 5 m 3 of solid material,
enough to cause vegetation damages. Plotted are the cases for years 2003-2007.
Landslides are one type of geological hazard. Geological hazards become so only where
population, services or structures are at risk. In this sense, although northwestern China is a
hot spot for landslides, the low population, by itself, reduces the hazard to a vanishingly
small likelihood. In contrast, India and Indonesia both have large populations under the
threat of storm-triggered landslides. It is reported (BNBP, 2009) that during the period 1998-