Fires have destroyed 1.2 million hectares of forest and grasslands in Bolivia this year, the government said, though environmentalists claim the true figure is much greater.
The news comes after leftist President Evo Morales suspended his re-election campaign on Monday to direct the government's response to a growing environmental disaster in the Bolivian portion of the Amazon rainforest, where wildfires have been raging since May.
Morales has faced mounting fury, both over his failure to act and over policies his critics say favor greater deforestation.
Bolivia's total forest area has been steadily shrinking in recent years, from 47.3 million hectares in 2005 to 43.8 million hectares in 2017, according to a study published by Bolivian environmental and human rights organisation the Solon Foundation.
The Friends of Nature Foundation NGO says the true extent of forest destruction this year is 1.8 million hectares.
Ecologists have attacked a law promulgated by Morales that offers incentives to burn forest areas to transform them into pastureland.
A group of 80 environmental and professional institutions are demanding that Morales recall the 2016 law.
The government, though, blames dry weather and strong winds for the voracious wildfires.
Morales's government has plans to plant 4.5 million hectares by 2030, to comply with commitments given to the United Nations, but environmental activist Marielle Cautin, also cited by the Solon Foundation, says that over the last three years "not even 50 000 hectares" have been planted.
On Tuesday, Morales mocked a G7 pledge of $20m to help fight the Amazon fires as "tiny".
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