Making sense of the numbers on the Brazilian Amazon

UNDERSTANDING what is happening to the world's largest tropical forest is hard: efforts to monitor deforestation in the Amazon are hampered by cloud cover, which can prevent satellites from getting a full picture of what's happening on the ground. The numbers also tend to ping around month by month, prompting alarm among conservationists one month and triumphalism from Brazil's government, which tries to prevent illegal logging, the next. The most recent release from Brazil's National Institute for Space Research showed a 473% increase in deforestation during March and April 2011 compared with the same period last year. This sounds alarming, and it may well turn out to be so. But it also comes in the context of falling deforestation. It will probably be a couple of years before it is possible to tell for sure whether the government's proposal to regularise land tenure in the Amazon region is resulting in more active chainsaws there.