The Amazon Tall Tower Observatory is a project of Brazil's National Institute of Amazonian Research and Germany's Max Planck Institute, O Estado de São Paulo said.
The tower, which will rise 325 metres from the ground, will be equipped with high-tech instruments and an observatory to monitor relationships between the jungle and the atmosphere. It will gather data on heat, water, carbon gas, winds, cloud formation, carbon absorption and weather patterns.
The project has been seven years in the making, with a site finally being selected far from any human presence, about 100 miles from Manaus, capital of the state of Amazonas, project coordinator Antonio Manzi told the newspaper.
The steel structure has been transported to the site on trucks and rafts from southern Brazil.
The Amazon jungle is one of the world's most sensitive ecosystems, with a powerful influence on the atmospheric release and intake of carbon.
"The tower will help us answer innumerable questions related to global climate change," said Paulo Artaxo, a project coordinator from the University of Sao Paulo. "We will gain a better understanding of the role of the Amazon and other humid tropical areas in climate models."
Agence France-Presse in Brasilia