Sao Paulo , Brazil ( CNN ) -- Brazilian President Dilma Rousseff on Friday vetoed 12 articles of a controversial forest bill approved by Congress last month , which was promoted by the powerful agriculture lobby but slammed by environmentalists . The legislation updates the complex Forest Code , regulating how much and what kind of land should be maintained as native forest and how much can be cleared for ranching and agriculture . Rousseff 's decision comes less than a month before Rio de Janeiro is due to host a high-profile U.N. summit on sustainable development . Many Brazilians had pushed for a complete veto , staging protests across the county and collecting 1.9 million signatures for a petition . Instead , Rousseff opted for line-item vetoes of articles that many said would grant amnesty to those who had illegally cleared land . She vetoed sections that would have eliminated reforestation requirements and sharply reduced the area around water sources that must be maintained as forest . The Amazon rainforest covers a huge area , roughly half as large as the United States , with about 60 % of it in Brazil . It is estimated that nearly a fifth of the Brazilian forest has been lost since 1970 , but over the past decade , authorities cracked down on clear-cutting , reducing the rate of deforestation by 80 % . Rainforest home to vast treasury of life . Former environment minister and presidential candidate Marina Silva has been a loud critic of the bill . `` It 's a setback without precedent after the 23 years of progress we 've made , '' she said . Sen. Katia Abreu , who represents the agriculture and ranching lobby , said the question of reforesting around rivers is more complicated than it appears . `` There are a lot of people who only have a tiny plot of land which is entirely inside the river margins , '' she said . `` What are they going to do with those people ? How are they going to reimburse them ? '' For years , the Brazilian government encouraged settlers to slash and burn forests in the sparsely populated center , north and west of the country for farming and ranching . Over three decades , Brazil went from being a food importer to an agricultural powerhouse . The new Forest Code has been an attempt to reach a compromise for farmers and environmentalists .
Forest Code regulates how much land should be maintained as native forest . Congress approved updates last month that were slammed by environmentalists . The new rules would allow logging on about half of the remaining acreage in national forests and other public lands — a move that could open up more than 1 million acres to timber sales over 10 years