RIO DE JANEIRO — When the smoke cleared, the Amazon could breathe easy again.

For months, black clouds had hung over the rainforest as work crews burned and chain-sawed through it. Now the rainy season had arrived, offering a respite to the jungle and a clearer view of the damage to the world.

The picture that emerged was anything but reassuring: Brazil’s space agency reported that in one year, more than 3,700 square miles of the Amazon had been razed — a swath of jungle nearly the size of Lebanon torn from the world’s largest rainforest.

It was the highest loss in Brazilian rainforest in a decade, and stark evidence of just how badly the Amazon, an important buffer against global warming, has fared in Brazil’s first year under President Jair Bolsonaro.

He has vowed to open the rainforest to industry and scale back its protections, and his government has followed through, cutting funds and staffing to weaken the enforcement of environmental laws. In the absence of federal agents, waves of loggers, ranchers and miners moved in, emboldened by the president and eager to satisfy global demand.