TheImprovement ofTropical and Subtropical Rangelands

Preface
Overgrazing, fuelwood collection, uncontrolled burning, the unregulated
exploitation of forest products, the growth of transporta.­
tion networks, agricultural expansion into marginal areas, major
social and economic changes are but some of the factors that have
contributed to the degradation of tropical and subtropical rangelands.
Periodic drought has intensified the impact of vegetation loss,
and it appears that this loss may, in tum, prolong drought. Because
rangelands comprise a substantial percentage of the earth's surface
and support millions of human beings, it is critical to understand .
the complex causes of this cycle of drought and degradation, and
to ensure that socially, economically, and scientifically appropriate
measures be formulated and implemented to stem degradation and
increase the productivity of rangelands.
The areas affected include some of the most vulnerable ecosystems
in the world. For example, once disturbed, dryland ecosystems
often require decades, or even centuries, to regain productivity. Nevertheless,
there can be no moratorium on the use of such "fragile"
lands; their products are vitally important. Although this report
focuses upon problems of range improvement in Africa and Asia,
many of the observations and recommendations could be applied to
the tropics and subtropics of Latin America as well.
The panelists and other individuals responsible for preparing this
report have no illusions regarding the ease with which productivity
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