ESTRUCTURA ARBÓREA DEL BOSQUE TROPICAL CADUCIFOLIO USADO PARA LA GANADERÍA EXTENSIVA EN EL NORTE DE LA SIERRA DE MANANTLÁN, MÉXICO. ANTAGONISMO DE USOS

Abstract

Tropical deciduous forests are among the least
studied forests in Mexico and the most diverse dry forests in the world. Extensive cattle
ranching and changes in land use to pastures
are important pressures for these forests,
which are considered among the most threatened in the world. This paper analyzes the
structure, species diversity and uses of tree
species of the tropical deciduous forest found
in the Northern portion of the Sierra de
Manantlan Biosphere Reserve. Four areas of
tropical deciduous forest used by cattle were
selected. These correspond to: a 10 year old
secondary vegetation corridor, two areas
of 15 and 20 year old forest, and another one
of approximately 30 years. Vegetation data were
collected through a randomly point centered
quadrant sampling and ethnobotanic data
through open interviews. We conclude that:
1) over 80% of the tree species in the secondary deciduous tropical forest in Zenzontla have
at least one use, 2) species diversity (Shannon-Wiener Index) in Zenzontla’s deciduous
tropical forests is higher than that of other
vegetation types found in the Sierra de
Manantlan, such as cloud forest, pine forest
and pine-oak forest, 3) species diversity and
use increase with time, 4) the number of individuals of forage species is less than the
number of individuals of the group of species
with other uses, and 5) size structure sugests
that in the future non-forage species will be
more dominant than forage species. Paradoxically, important areas of the deciduous tropical forest used for forage and other uses
(mainly medicinal and food) are under pressure for substitution for pastures.