HIGH-RESOLUTION IMAGE TO MAP BAMBOO-DOMINATED GAPS IN THE
ATLANTIC RAIN FOREST, BRAZIL
L. S. Araujo 3 , G. Sparovek 3 , J. R. dos Santos b , R. R. Rodrigues 3
a ESALQ, University of Sâo Paulo, Piracicaba, Sâo Paulo, Brazil - (lsaraujo, gerd, rrr)@esalq.usp.br
b DSR, National Institute for Space Research, Sâo José dos Campos, Sâo Paulo, Brazil-jroberto@ltid.inpe.br
KEY WORDS: Ecology, Land Cover, Forestry, Landscape, Interpretation, Quickbird, High Resolution
ABSTRACT:
This study presents the results referring to the analysis of QuickBird high resolution satellite images to establish patterns associated
to the landscape dynamics in bamboo forests at the Intervales Park (Sao Paulo State, Brazil), considering its ecologic aspects. The
methodology was based on visual image interpretation, as a preliminary step for digital processing. The results show the possibilities
for the use of these high resolution data to map forests with bamboo dominance as well as for monitoring phenologic cycles of these
dominant species. The visual interpretation was an adequate technique for our study, emphasizing that the knowledge of the
ecological aspects from these forest typologies was of fundamental importance to understand the patterns mapped with this image.
1. INTRODUCTION
Presently remote sensing data are fundamental tools to survey
natural resources, being of fundamental importance for decision
taking in several areas of public policies. In Brazil, several
methodologies using orbital data were developed and applied
exclusively to map and monitor vegetation including several
Brazilian biomes such as presented at the “Atlas of forest
remnants from the Mata Atlantica" (SOS Mata Atlantica, INPE
2002).
At Atlantic Forest (Mata Atlantica), composed presently by
fragments distributed along the Brazilian coast, the region
known as “Continuous of Paranapiacaba” is considered one of
the most important remnants of this biome. Located at southern
Sao Paulo State and formed by the junction of Parks Intervales,
Turlstico do Alto Ribeira and Carlos Botelho and the Ecologic
Station of Xitue, the Continuous includes approximately 150
thousand ha of vegetation composed almost completely of
Ombrophilous Dense Forest (BIOTA/FAPESP, 2008). Recent
diagnostics in the field however, associated with the analysis of
aerial photographs, present extensive forest areas with
dominance of bamboos (Sao Paulo, 2007), which were not
detected on previous surveys (BIOTA/FAPESP, 2008; SOS,
INPE, 2002). This fact evidenced the need to map the
distribution and monitor the possible expansion of these forest
formations at a compatible scale with this landscape.
The bamboos belong to the family of the Poaceae and are
typical components of the humid forest from Mata Atlantica
(Rizzini, 1979). Due to its’ characteristics of fast colonization
from the rhizomes and of its’ invasive habits, they are
frequently related to disturbed environments (Wong, 1991), to
clearings of natural and human origin, interfering on both forest
structure and regeneration (Griscom & Ashton, 2003). Besides
that, they have a long life cycle between 20 and 60 years,
culminating at a phase of sexual reproduction with a high
production of seeds and massive mortality of population
(Janzen, 1976), restricting the knowledge of the life cycle from
these plants to a few species. These associated propagation
characteristics allow its dominant establishment which results in
differentiated landscape patterns, of fundamental importance to
understand the ecological aspects associated to these bamboo
sites in studies of forest dynamics.
In Brazil studies of bamboo formations with remote sensing
techniques were performed in the SW Amazon, where there are
extensive areas dominated by the genus Guadua (Nelson et al.,
2006). Using a series data from 28 years of Landsat-MSS,
Landsat-TM and MODIS/TERRA, Nelson & Bianchini (2005)
monitored the life cycle of the bamboo population of genus
Guadua in Acre State, during two population mortality events
in 1976 and 2003-04, learning on the reproductive cycles of
these species. Despite differences in structure and floristic
composition, forest classes with and without bamboo were not
well discriminated with JERS-1 (Santos et al., 2000) and
ASTER/Terra (Mendoza et al., 2004) image data in sections of
the Amazon.
In Acre State, bamboo forests occupy large areas, with one or
two dominant species. At Intervales Park, in the Continuous of
Paranapiacaba, field observations show clearings occupied by
different bamboo species occurring jointly with sections of
dense forest. This landscape mosaic and the extremely
mountainous topography of the region, make mapping of these
areas difficult with medium resolution data. Being so, high
resolution images become an additional information source for
these studies on bamboo, with similar resolution of aerial
photographs, but with distinct spectral characteristics which
allow detailed mapping of forest features using automatic
classification procedures.
Taking into account the complexity of these high resolution
data and consequently of the associated processing, the visual
interpretation is still a quite frequently used procedure, as an
alternative or in parallel to digital procedures (Buchanan et al.,
2008; Tottrup et al., 2007). Based on parameters such as color,
texture, shape and pattern (Lillesand & Kiefer, 1994), this
technique allows the direct inclusion of knowledge from the
analyst in the field during the mapping process, fundamental to
understand this forest dynamics in areas with bamboos.
In this context, the objective of this paper is to evaluate the
potential of high-resolution images to establish patterns