Geoscience Reference
In-Depth Information
CHAPTER 5
Assessing the Hydrological Effects of
Forest Plantations in Brazil
Walter de Paula Lima
1
, Silvio Frosini de Barros Ferraz
1
, Carolina Bozetti Rodrigues
2
and Maureen Voigtlaender
2
1
Depto de Ci encias Florestais, ESALQ, Universidade de S ao Paulo, Brazil
2
Instituto de Pesquisas e Estudos Florestais (IPEF), Piracicaba, Brazil
Introduction
on rivers and their ecosystems were largely
unknown in the tropics (Bonell and Black,
1993). This chapter describes how the hydrological
effects of plantation forest management in Brazil
have been assessed, and compares early results
from a programme of experimental studies with
conclusions from similar studies elsewhere in the
world. This hydrological perspective is important
because improved understanding of the impacts
of
The traditional focus for the conservation and
management of rivers has been the channel
and adjacent corridor; however, a fundamental
requirement is an understanding of how land
use affects the hydrological character of the
catchment (Newson, this volume). This is because
the development, form and functioning of river
channels and their floodplains are strongly
influenced by hydrological factors acting at a
regional and catchment scale (Newson, 2009).
Changes in land use often have profound effects
on the character and the behaviour of rivers.
Deforestation and afforestation of river catchments
are good examples, and are particularly relevant in
relation to widespread public interest concerning
the loss of native tropical rain-forest and, more
recently, policies that promote tree-planting for
carbon sequestration (Wright
et al
., 2000).
Newson (2009) observed that 'Perhaps the
major outstanding forest hydrology problem facing
river basin development is in the humid tropics
where timber extraction and its other social and
environmental impacts have resurrected many of
the myths deriving from simplistic observation
or blind translocation of temperate-zone science'.
A lack of controlled catchment experiments has
been cited as a major reason why the effects
plantation
forestry
will
help
to
encourage
more
sustainable
land
and
water
management
in
catchments,
with
consequent
benefits
for
river ecology.
In spite of their economic importance, forest
plantations have attracted widespread criticism
from environmentalists, social organizations and
academics. These views are based, in part,
on popular opinions, beliefs and myths. A
good example is the controversy about the
effect of eucalyptus (
Eucalyptus
spp.) plantations
on water availability (ACIAR, 1992; Cossalter
and Pye-Smith, 2003), although the debate
applies equally to forest plantations generally
(Andreassian, 2004). Despite improving scientific
knowledge the controversy remains; this is because
the debate is not simply about calculating the
water uptake by eucalyptus or whether streams
and soils will dry out - it is far more complicated
and involves political, economic, environmental,
