RIO DE JANEIRO, Brazil -- Carlos Minc never wanted to grow up to be the environment minister of Brazil. The self-described former "student militant revolutionary," who spent time behind bars in the 1960s for resisting his country's military dictatorship, had more grandiose goals in his younger years.

"I wanted to be Che Guevara," he said.

But in his first six months as Brazil's top environmental official, Mr. Minc, 57, has found the level of combat more than sufficient in this bureaucratic post, which he took over in May after the abrupt resignation of Marina Silva, an Amazon native who had achieved iconic status in environmental circles for her defense of the world's largest rain forest. "I'm in a state of shock," he said. "Absolutely."

In his first week on the job, he recalled, he was asked at a meeting of world environmental officials in Bonn, Germany, whether the Amazon was "all going to turn into dust" under his stewardship.

"That was the first question," he said.

Since then, Mr. Minc's tenure has been marked by a flair for bold if controversial strokes. He has sent the military to seize thousands of cattle on illegally deforested land. He released a list of the nation's 100 top deforesters and named the government's land reform agency as the leading culprit. He has pledged to cut by about half, to 13 months, the time it generally takes large development projects to receive environmental licenses, a position some environmental activists view with skepticism.

"Every action I take is on TV. I'm not embarrassed of what I do," Mr. Minc said in an interview at his Rio de Janeiro home. "You need to make examples. You need the army. You need TV. Or people think they can destroy the forest and nothing's going to happen."

The resignation of Ms. Silva, a former rubber tapper who had served as minister for more than five years, caused an uproar among activists around the world who feared that her departure would lead to more lax environmental oversight.

During her tenure, Brazil created 59 million acres of protected areas, or nearly half of all protected lands in the country, Ms. Silva said. The amount of forest cleared in the Amazon fell from a high of more than 10,000 square miles in 2004 to 4,400 square miles in 2007, the third-straight year of decline and the lowest level since 1991, according to government statistics.

"It is perhaps too early to tell" about Mr. Minc's performance as minister, said Stephan Schwartzman, an Amazon specialist at the Environmental Defense Fund in Washington. "But it is certainly the case that Mr. Minc follows an environment minister who has left an incredible legacy."

Ms. Silva said she resigned because of mounting pressure from inside and outside the government to roll back measures she championed, such as the denial of credit from state banks to anyone involved in deforestation in the 36 municipalities with the highest rates of clear-cutting.

"I had the feeling that my resignation could create a political movement to keep the measures, and I believe this has happened," she said. "The president felt strengthened."

Several environmentalists said they have been cautiously optimistic so far that Mr. Minc does not intend radical departures from Ms. Silva's policies, though some expressed concern that he seemed more willing to approve large-scale development projects planned under President Luiz Inacio Lula da Silva.

"I think Lula needed somebody who would not be perceived as an enemy of the environment, because he was losing Marina Silva," said Claudio Maretti, conservation director of World Wildlife Fund-Brazil. "He was also looking for somebody that would not make too many problems for him for his projects to build infrastructure -- roads and airports and dams -- that has characterized his government."

Some Brazilian cattle ranchers have greeted Mr. Minc's appointment with relief, said John Carter, an American rancher and conservationist who has lived in the Amazon for more than a decade. Under Ms. Silva, he said, the government's attitude was "no to everything, and yet the trees kept falling."

"You're not going to stop deforestation -- the economics are just too strong. He understands how industry and development need to be harnessed to bring about change," Mr. Carter said. "The 21st century requires the forest to pay for itself. We're going to have to have economic incentives."