Selective Logging in the Brazilian Amazon

Abstract

Amazon deforestation has been measured by remote sensing for three decades. In comparison, selective logging has been mostly invisible to satellites. We developed a large-scale, high-resolution, automated remote-sensing analysis of selective logging in the top five timber-producing states of the Brazilian Amazon. Logged areas ranged from 12,075 to 19,823 square kilometers per year (+/-14%) between 1999 and 2002, equivalent to 60 to 123% of previously reported deforestation area. Up to 1200 square kilometers per year of logging were observed on conservation lands. Each year, 27 million to 50 million cubic meters of wood were extracted, and a gross flux of approximately 0.1 billion metric tons of carbon was destined for release to the atmosphere by logging.

Detecting anthropogenic disturbance in tropical forests

“…As shown by Asner et al [5] and Souza et al [6], detecting cryptic forms of tropical forest degradation is a key challenge for researchers that will hopefully be overcome as new techniques and high-resolution imagery become more readily available as monitoring tools. Further progress, however, is yet to be made in quantifying the extent and intensity of less-visible forms of nonstructural habitat disturbance underneath the forest canopy.…”

“…Total area affected by deforestation (green circles), selective logging (red squares) and surface fires (blue diamonds) throughout Brazilian Amazonia during the past century. These estimates are based on a range of sources, including the annual deforestation statistics made available by INPE [5]; a conservative estimate of basin-wide logging disturbance [5,8,16]; and a conservative estimate of the area affected by surface wildfires [7,17].…”

“…It is difficult to distinguish with remote sensing against the background of natural treefall-gap dynamics. In a recent study, Asner and colleagues [5] used an automated, high-resolution remote-sensing technique (spectral mixture analysis; SMA [5]) to map logged areas from 1999 to 2002 in the top five timber-producing states of Brazilian Amazonia. Their analysis of 480 Landsat ETMC scenes, which detected small logging gaps (!0.5 ha) and associated understorey disturbance caused along skid trails and logging decks, shows that an area of 12 075-19 823 km 2 was selectively logged each year.…”

“…Here, we discuss some of these hidden threats while focusing primarily on the Brazilian Amazon, which is experiencing the highest absolute rate of forest loss worldwide (O26 230 km 2 during 2004 [4]). In addition, two recent remote-sensing studies [5,6] indicate that less-detectable patterns of human-induced perturbation to the forest biota have been underestimated. …”

Avaliação do desmatamento no estado de Rondônia entre 2001 e 2011

“…Estas áreas de florestas impactadas pelo fogo e por atividades madeireiras podem alcançar dimensões semelhantes às áreas desmatadas na região Amazônica (Nepstad et al, 1999;Asner et al, 2005;Matricardi et al, 2010Matricardi et al, , 2013.…”