Forest loss density (km2 forest loss per 100 km2 land area) in Amazonia, as calculated using the GFC product for two time periods: (a) 2001–2007 and (b) 2008–2014 using ArcGIS 10.4.1 ( Histogram indicates the number of gridcells for each density class. Graphic: Kalamandeen, et al., 2018 / Scientific Reports

By Morgan Erickson-Davis
2 February 2018

(Mongabay) – A new study finds small-scale deforestation in the Amazon rainforest has been increasing over the past decade, with new hotspots emerging in Bolivia and Peru. The news somewhat dampens Brazil’s touted successes at combatting deforestation, with researchers saying the country’s forest monitoring system is not capable of detecting small areas of forest loss.

Over the past decade, numbers from Brazil’s National Space Research Institute (INPE) have have shown big drops in deforestation in the Brazilian Amazon. After a spike of around 27,000 square kilometers of forest lost in 2004, INPE data indicate deforestation declined precipitously to less than 5,000 square kilometers in 2012. Since then, the data show deforestation in the region has remained relatively low compared to years past, with experts attributing the decline largely to the strengthening of environmental regulations in the mid-2000s.

However, Brazil’s drop in deforestation may not be quite as big as those numbers suggest. INPE uses a satellite monitoring system called PRODES to look for tree cover loss in the Amazon, a system that has been lauded by conservationists as a big force behind the deforestation decline in the Brazilian Amazon. But PRODES can only detect canopy gaps larger than 6.25 hectares, meaning that deforestation events smaller than that may be missed.

To get a more comprehensive look at deforestation trends in the Amazon rainforest, a team of scientists from the UK and Brazil used another satellite monitoring dataset, one that can detect tree cover loss at a much smaller resolution. Produced by the University of Maryland, this Global Forest Change (GFC) dataset can detect losses in tree cover at a scale of 30 meters. Their results were published recently in Nature’s Scientific Reports.

Using the GFC dataset, the team looked at deforestation events across Amazonia that happened between 2001 and 2014, finding that the vast majority – 96.4 percent – of forest loss patches were smaller than 6.25 hectares. Brazil and Bolivia were the only Amazon countries where their respective average patch sizes were larger than 1 hectare. Brazil’s average patch size was 15.6 hectares, but the team found it has been declining since 2004. The researchers write that this shrinking average patch size means that large-scale deforestation events are declining and small ones are on the rise.

In total, the data indicate 34 percent of forest loss patches in the Brazilian Amazon were smaller than 6.25 hectares. In other words, the study found that more than a third of deforestation events that happened in Brazil’s rainforests between 2001 and 2014 may have been too small to be detected by the PRODES monitoring system. [more]

Amazon rainforest hit by surge in small-scale deforestation, study finds

ABSTRACT: Understanding forest loss patterns in Amazonia, the Earth’s largest rainforest region, is critical for effective forest conservation and management. Following the most detailed analysis to date, spanning the entire Amazon and extending over a 14-year period (2001–2014), we reveal significant shifts in deforestation dynamics of Amazonian forests. Firstly, hotspots of Amazonian forest loss are moving away from the southern Brazilian Amazon to Peru and Bolivia. Secondly, while the number of new large forest clearings (>50 ha) has declined significantly over time (46%), the number of new small clearings (<1 ha) increased by 34% between 2001–2007 and 2008–2014. Thirdly, we find that small-scale low-density forest loss expanded markedly in geographical extent during 2008–2014. This shift presents an important and alarming new challenge for forest conservation, despite reductions in overall deforestation rates.

Pervasive Rise of Small-scale Deforestation in Amazonia



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