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 CEPS Research |
The extent of deforestation varies by state, with
Rondônia being the most recent state to undergo transformation from a remote
intact forest to a nearly-developed frontier. This 1991 Landsat Thematic
Mapper satellite image shows the "fishbone" pattern of deforestation
along the BR-364 highway. This road runs the length of the state and its
opening in the early 1970's led to Rondônia's rapid development and widespread
land degradation. Today much of the cleared land along BR-364 is abandoned
or under-used grazing land. 
The problems of linear road building and land allocation
became apparent after several rainy seasons. Though Amazonia lies in a broad
basin much of the topography below the forest canopy is rolling. 
The straight roads cut across the local relief, and during the wet season
washouts closed many roads to traffic. In the early 1980's planners considered
topography when they outlined the development of "Projeto Machadinho"
under the POLONOROESTE Program. Machadinho has a dendritic pattern of roads
that works with the local terrain and drainage.
Machadinho's planners made an effort to work with
the local environment, but no amount of planning could mitigate the region's
poor soil conditions. The Empresa
Brasileira de Pesquisa Agropecuaria - Nucleo de Monitoramento Ambiental
e de Recursos Naturais por Satelite (EMBRAPA-NMA) reported that
by 1993 over two thirds of the original settlers of Machadinho had left
their allotments after several years of unsuccessful farming. 
The remaining farmers have worked hard to cultivate an optimal combination
of perennial and annual crops. This 80-year-old woman harvests cafe robusta
on her family's farm in Machadinho. The coffee beans will be sold for a
small amount of cash, giving her family a standard of living slightly above
subsistence. Her family was interviewed in 1993 by EMBRAPA-NMA researchers
who, with the support of the NGO ECOFORCE,
periodically track the successful farmers of Machadinho.
Abandoned land in Machadinho, and throughout Amazonia, is consolidated by ranchers and other farmers, or left to regrowth. The rapid growth of secondary forest is evident in this satellite image and ground photo. This area lies about 70 kilometers north of Manaus in Amazonas state, and it is the site of the joint Smithsonian Institution - Instituto Nacional de Pesquisas da Amazonia - Biologically Dynamic Forest Fragment (BDFF) Project. BDFF is one of several ongoing projects under the Smithsonian's Biological Diversity Program.
The project studies parcels of primary forest of
varying size on the fazendas, or cattle ranches. The ranchers have cooperated
with the institutions by leaving the forest fragments uncut and by allowing
access to researchers. 
The narrow red swath (center left) in this Landsat image was cut in the forest in July 1991 to isolate a 100 hectare reserve. The ground photo shows the swath in May 1993, and reveals thick secondary growth aged less than two years. The height of the growth ranges from 3 to 5 meters.
The rapid growth of secondary succession complicates
deforestation estimates with satellite imagery. By about age 25 years the
secondary growth takes on spectral and structural qualities of a primary
forest canopy. 
Extensive areas of old secondary growth are found in the eastern Amazonian
states of Para, Tocantins, and Maranhao. Secondary growth in Amazonia lacks
the species diversity of primary forest. Simply classifying forest and non-forest
in deforestation estimates understates the problem. The INPE estimates that
old secondary growth covers 97,000 square kilometers of Amazonia. This figure
does not include land abandoned during the past 20 years. Secondary succession
in selected sites will be mapped to monitor the process of regrowth. The
proposed study areas are Machadinho and the BDFF associated fazendas north
of Manaus. Initial work will be based on Landsat TM data.
| Revised:
April 2, 2001 (jh) ©1994-2001 National Air and Space Museum |
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