New maps detail how soybean and other farmers are spreading into the Amazon, the world's biggest rainforest, the government's National Statistics Office (IBGE) said.
In a statement on Thursday, it said that the southern savannah area of the Amazon region, notably Mato Grosso, Tocantins and southern part of Maranhao state, offered the greatest potential for soy farmers.
The map of the Amazon agricultural frontier, based on 2003 data, was one of 10 covering political, social and logistical themes which for the first time summarize the effects of human activity on the region.
Deforestation was greatest in Para where 207,000 square kilometers of trees have been felled, notably along the Trans-Amazon highway and the BR-163 linking the region with Mato Grosso and southern Brazil.
In neighboring Mato Grosso, Brazil's No. 1 soy state, tree felling was greatest along the state's main highways.
Production of soybeans and other grains is also expanding in Tocantins, Maranhao and in some parts of Amazonas, Roraima and Rondonia states, IBGE said.
Rondonia, bordering Bolivia, was the most severely affected with 28.5 percent of the state deforested, IBGE said.
The Amazon, the world's largest tropical rainforest covering an area larger than India, is estimated to provide a habitat for a quarter of all species.
Preliminary figures last September showed that Amazon deforestation slowed 11 percent in 2006.
A government program had cut the rate of land clearance by 52 percent over the past four years, Environment Minister Marina Silva was quoted by Agencia Brasil as saying.
But an estimated 16,700 square kilometers of forest -- an area about the size of Hawaii -- was lost during the 2005/06 logging season.
The Amazon covers 10 Brazilian states and 3.8 million square kilometers, or 59 percent of the country. It was also home to 20.3 million Brazilians, or 12.3 percent of the population, according to the 2000 government census.
Population growth, due to government policies encouraging migration and expansion of timber, livestock and soy farming, was the main cause of deforestation, IBGE said.
Deforestation accelerated in the 1970s with the arrival of ranchers and a fresh surge started in the 1990s as large scale soy farmers moved in.