TheImprovement ofTropical and Subtropical Rangelands

REGIONAL RESOUROE ASSESSMENT 75
only broad generalizations are expected at the resource assessment
level. The purpose is to identify relatively homogeneous climatic
zones that could support one or a limited set of vegetation types.
VegetatlOll
Since climate cannot be observed directly, vegetation patterns
often are mapped and interpreted as indicators of climate. Many
assessments produce a composite map of climate and vegetation. Intended
to serve as an indicator of climate, it is also an important
management tool. An examination of the environmental history of
the region and previous resource assessments, as well as an interpretation
of the information generated during the mapping phases
of the resource assessment, allows the development of a profile of
the type of vegetation that might be found in different parts of the
region under "natural- conditions. This model of potential or climax
vegetation ultimately may serve as a guide for range improvement
by suggesting what might be achieved.
It is also necessary to inventory actual vegetation patterns currently
found within the region. A vegetation inventory includes maps
and descriptions of associations, at a minimum, and could also include
information on cover, production, and numbers of plants. Special
attention should be given to determining the value ofcomponent
species for forage, fuel, and other uses.
At this level of study, the goal is to provide information on
the distribution of resources and, by comparing the results with the
estimate of potential or climax vegetation, to identify areas where
there are opportunities for range improvement, and to indicate areas
where problems exist. Perhaps most important, the inventory of
actual vegetation provides a picture of conditions at the beginning
of the project that can serve as a benchmark for measuring general
progress during the course of the project.
Geology
At the resource assessment level, geology is described in general
terms. Primary consideration is given to identifying rock type and
structure within the region. Geologic information provides a structural
framework for the region and also is used to help form a general
understanding of regional hydrology and the evolution of landforms
and soils by providing clues to the origin, age, and mineralogical
composition of surface materials.