The ceiling fans spinning at full speed were not enough to cool the room, but the farmers gathered in Irituia's town hall are used to the oppressive heat of the Amazon.
Most of the plastic seats were empty but the 30 or so people at the meeting in Irituia were paying a lot of attention to discussions about environmentally sound agriculture in their biodiverse part of the world.
"We are not many yet but we notice that little by little more of us are realising that sustainable farming is the only way to go, and that we don't have to be enemies of the environmentalists," said Mauro Lucio Costa, chairman of the Farmer's Union of Paragominas.
Paragominas, like Irituia located in the state of Para, topped the deforestation ranking in Brazil in 2008 - and went on a government blacklist.
But since then sawmills have been closed and farms more strictly monitored.
"It's useless nowadays to cut the trees at night or away from the roads to get away with deforestation because now they are watching us with satellites. I tried that not to long ago and was heavily fined," one farmer told the meeting.
But farmers who have tried to adopt a more environmental approach get more raised eyebrows than approving nods here, especially as tensions were heightened by the debate in Congress over changes to Brazil's Forest Code.
This environmental law stipulates that landowners in the Amazon must keep 80% of their terrain forested; that drops to 20% for other parts of Brazil.
Proposals to change the legislation pitted those who see development and economic growth as the highest priority (including many farmers, though not all) against those who see conservation as the key issue. That group includes environmentalists and a large part of the scientific community.
"These NGOs are an international mafia that hold businesses as hostages by threatening to soil the names of those who oppose [them]. These groups thrive when there's conflict," says Katia Abreu, head of Brazil's powerful National Agriculture Confederation (CNA).
"They want to rip Brazilian farmers out of the ground as if we were some kind poisonous weed."
The reform of Brazil's Forest Code has been debated for more than 15 years.
Just a few weeks ago it seemed that a version of the bill that eases restrictions on the use of forest land would be approved by the Chamber of Deputies.
But environmentalists managed to garner more political and public support to bring the vote to a halt.
"Even though the Forest Code has been under intense discussion for many years it was only recently, after it was approved in congressional committees, that the media took an interest in it," says Paulo Adario, co-ordinator for Greenpeace's Amazon programme.
"I think the pressure from national and international public opinion was essential to stop the approval of the bill the way the farmers wanted it and to get President [Dilma] Rousseff's government to support some of our concerns," said Mr Adario.
Among the proposed changes that worried environmentalists were plans to:
The proposals were the focus of intense wrangling. On 24 May, deputies approved the overhaul of the forest code. It now goes to the Senate and President Rousseff for approval.
Environmentalists argue that the changes and loopholes in the legislation pose a big threat to the Amazon rainforest.
"The farmers are trying to leave doors open to allow for the permanence of plantations in highly sensitive areas like slopes and hilltops," says Paulo Barreto, a researcher at of the Amazon Institute for Mankind and the Environment (Imazon).
Many environmentalists believe that a recent reported increase in Amazon deforestation was caused by farmers trying to clear land before the new Forest Code code is approved.
This would mean that their lands could be recognised as established farmland.
But Mrs Abreu argues that the environmentalists' concerns have more to do with ideology than with science.
"Just look at the world's history and you'll see that everywhere agriculture developed along the rivers because our activity depends on water, it's quite obvious," she said.
Mrs Abreu was critical of the Brazilian Society for the Progress of Science (SBPC), which has called for more for more research before the forest code is changed.
That view, Mrs Abreu said, was "highly politicised".
Environmentalists say that they understand the need for more food production.
But they argue this can be done by increasing the productivity of existing farmland, not clearing more of the Amazon.
Cattle farms in the Amazon have an average productivity of less than one head per hectare (2.5 acres).
"I have invested in better varieties of pasture and in fertilisers and I have an average of 2.5 cows per hectare in my farm. I also plant corn," says farmer Percio Barros de Lima.
"When I bought this farm in 1974 it still had about half of its area covered with original forest, which was what the law required at the time. Since then we have managed to develop by increasing productivity and without clearing any new areas," says Mr Lima.
"I hope the new forest code will make all rules for our activity clearer so we'll be able to work without so many uncertainties about the future."