by Candace Piette, BBC News, Amazonas - "Deforestation is linked to economic factors," says Paulo Barreto, senior researcher at Imazon, a non-governmental organisation, in his offices in Belem, the capital of the Amazonian state of Para. With high food and commodity prices around the world, the hunger for cheap land in the Amazon - which costs a tenth of land in Brazil's south and south-east - seems set to increase.