Halting deforestation is essential to preventing dangerous global warming, the energy and climate change secretary, Ed Miliband, has told indigenous tribesmen and women on a visit to the heart of the Amazon rainforest.

Cutting down trees causes 17% of global carbon emissions — more than global transport — and much of it happens in the Amazon. But mechanisms by which rich nations can persuade forested nations that the trees are worth more standing than felled have been problematic, with issues of land ownership, the role of indigenous people and corruption hindering progress.

"We can only get an agreement on climate change if it involves Brazil and it involves forestry," Miliband said during a boat trip on the Xingu river near the remote indigenous community of Pavuru.

The world's governments will gather in Copenhagen in December to agree a global treaty on fighting global warming, with deforestation very high on the agenda. "There is no solution to the question of climate change without forestry," he added.

During the five-day diplomatic offensive Miliband will meet environmentalists, policy makers and scientists as well as the people on the frontline of Brazil's battle against climate change – Brazil's indigenous communities, cattle ranchers and soy farmers.

Yesterday afternoon he touched down in the Xingu National Park — a sprawling indigenous reserve home to 5,000 Indians from 14 different ethnic groups — to discuss the perils of climate change and deforestation with those who inhabit the world's greatest tropical rainforest .

Addressing the Indians in a straw-roofed auditorium in Pavuru, Miliband said:

"We recognise the very important steps that you are taking to protect the environment against illegal activities and other threats against the forest and we are very grateful to you. But we know there is more that we can do to help you manage the forest in a sustainable way."

Tribesmen and women had travelled from across the 2.8m hectare Xingu National Park to reach this tiny village at the heart of the reserve. "They told us the minister wanted to talk to us about deforestation, about water," said Tom Aweti, 48, the leader of the Aweti people who had travelled several hours by boat to reach the meeting. "We will listen."

But the Indians also came to be heard; from the early hours of Sunday dozens of boats carrying tribal leaders and their families began mooring on Pavuru's small beach. Others came onboard a single motor aeroplane.

"The white man is invading our land," Chief Tinini, from the Xingu's Juruna village, told Miliband, holding a tribal spear in his right hand. "Many fish are dying," he added, blaming the construction of hydroelectric plants in the Xingu region. "Our children will starve."

Napiku Ikpeng, 33, from Pavuru's indigenous association, said he was concerned government infrastructure plans, involving roads and hydroelectric plants, would harm his peoples' way of life. "We aren't against economic growth… but this growth has to respect the Indians who live in this place," he said.

Speaking to the Guardian after the meeting Miliband said he had been shocked "seeing the actual logs piled up and the illegal roads that have been built" during a flight over the Amazon rainforest.

"The Amazon forest is such a beautiful place when it is untouched and then you see these scars on the landscape of the deforestation, bigger and bigger scars," he said.

"Brazil is up for a deal we just need proper ambition from developed countries, the right financial architecture in place," he added.