Updated

Deforestation in the Amazon rain forest has dropped 18 percent over the past 12 months, falling to the second-lowest level in a quarter century, Brazil's environment minister said Wednesday.

Izabella Teixeira told participants in a news conference that 4,848 square kilometers (1,870 square miles) of rain forest were destroyed between August 2013 and July 2014. That's a bit larger than the state of Rhode Island.

The figures were down from 5,891 square kilometers (2,275 square miles) razed during the same period a year earlier, in the wake of the adoption of a controversial bill revising the Forest Code. The measure, which passed in 2012 after more than a decade-long effort by Brazil's powerful agricultural lobby, mostly eased restrictions for landowners with smaller properties, allowing them to clear land closer to riverbanks.

Wednesday's lower figures came as a surprise because many environmental groups had been warning of a second consecutive spike in the annual deforestation numbers, as the forest continues to be razed to make way for grasslands for cattle grazing, soy plantations and logging. Teixiera insisted the numbers were accurate.

Marco Lenini, who coordinates the Amazon program for the World Wide Fund for Nature's Brazil branch, called the announcement "good news," adding, "We were surprised."

"The major message is OK, is good: Brazil has been advancing," he said, though he cautioned, "It doesn't mean that deforestation issue is over."

"We are still very far from this goal of having minimum deforestation," Lenini said, referring to Brazil's pledge to reduce deforestation to 3,900 square kilometers (1,506 square miles) per year by 2020.

Brazil's lowest recorded deforestation figure since 1988, when the country began to use satellites to monitor the forest, came in 2012, when 4,571 square kilometers (1,765 square miles) were clear-cut.

In addition to being home to around one-third of the planet's biodiversity, the Amazon is considered one of the world's most important natural defenses against global warming because of its capacity to absorb huge amounts of carbon dioxide. Rain forest clearing is responsible for about 75 percent of Brazil's emissions, as vegetation is burned and felled trees rot.

The Amazon extends over 6.1 million square kilometers (3.8 million square miles), with more than 60 percent within Brazil's borders.